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January 13, 2020
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https://www.sciencedaily.com/releases/2020/01/200113111149.htm
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Global database of all bird species shows how body shape predicts lifestyle
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A database of 10,000 bird species shows how measurements of wings, beaks and tails can predict a species' role in an ecosystem.
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Given that many bird species perform important ecological functions, such as pollinating plants, spreading seeds, or controlling pests, the database may help scientists to understand and predict how the loss of species will affect ecosystem health.A global team of researchers, led by Imperial College London and University College London, visited museums around the world to find specimens of nearly 10,000 species, covering more than 99 percent of all known bird species. Their results, and the database, are published today in The link between body form of each animal species and aspects of their lifestyle, including diet, has previously been proposed, but this is the first time it has been confirmed at such a large scale and with such precise detail.The senior author of the study, Dr Joseph Tobias, from the Department of Life Sciences at Imperial, said: "To compile measurements for all bird species has been a massive undertaking. That's particularly the case considering the hundreds of explorers and biologists over the last 150 years who collected and curated the 70,000 museum specimens on which this work is based."Predictions of a species' contribution to an ecosystem are often made using estimates of their evolutionary relationships with other species -- relying on the fact that closely related species tend to be more similar in function than distantly related species.However, the new database shows that body measurements offer a far better prediction overall, as some very distantly related species have evolved similar bodies to equip them for similar lifestyles or dietary preferences.For example, the family of auks, which includes puffins and guillemots, have very similar body shape to penguins, despite evolving in opposite hemispheres. Both have beaks, bodies and wings adapted to swimming and catching fish underwater.The concept -- called convergent evolution -- is far from new, but the new dataset provides the clearest picture yet of its widespread influence across an entire class of animals at a global scale.The team looked at nine body measurements including the dimensions of beaks, tails, wings and legs as well as body mass, and compared these to a bird's diet and foraging behaviour -- for example whether it primarily catches invertebrates in the air, on the ground, or under water.Some associations are obvious, such as longer wings in species that spend much of their time flying, or longer legs in ground-dwelling species. However, the team found that the combination of all body measurements was highly predictive of even subtle differences in lifestyle, and ecosystem function, across all species.The study's first author, Dr Alex Pigot of UCL's Department of Genetics, Evolution & Environment, said: "Our results suggest that evolution is a predictable process. If we were to 're-run the tape of life', then evolution likely would once again lead to very similar-looking organisms to the ones we see today."Being able to quantify each animal's vital role in the functioning of the biosphere is really important in understanding impacts of the current extinction and climate crisis."Dr Tobias said: "The link we show between body form and function has some potentially important applications, and paves the way for the use of similar data to investigate the role of biodiversity in ecosystems."For example, further studies can use our database to predict the effects of climate and land-use change on ecosystem function, and to set appropriate targets for wildlife conservation."
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Extinction
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January 10, 2020
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https://www.sciencedaily.com/releases/2020/01/200110093833.htm
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Novel avian species: 10 new bird taxa in islands of Wallacea
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Birds are the best known class of animals, and since 1999, only five or six new species have been described each year on average. Recently, a joint research team from the National University of Singapore (NUS) and the Indonesian Institute of Sciences (LIPI) made a quantum leap in the discovery of cryptic avian diversity by uncovering five bird species and five subspecies new to science.
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The team, led by Associate Professor Frank Rheindt from the Department of Biological Sciences at NUS Faculty of Science, found the birds in three small island groups off Sulawesi, Indonesia. The islands are situated in Indonesia's Wallacea region, an archipelago at the interface between the Oriental and Australian biogeographical realms, named after Sir Alfred Wallace, who was the most famous historical collector exploring the area.The results of the study, which were published in the journal Sea depth is an important and long-neglected factor in determining the distinctness of an island's terrestrial communities. The Earth undergoes periods of glacial-interglacial cycles, leading to the formation of land bridges between shallow islands during ice ages, allowing fauna of the different islands to interbreed. Deep sea islands, which have always been isolated, and high elevation islands are more likely to harbour endemism due to absence of land connections even during glacial cycles.Guided by this knowledge, Assoc Prof Rheindt and his team concentrated their research efforts on the islands of Taliabu and Peleng, which are located off the north-eastern coast of Sulawesi, as bathymetric data indicate the presence of deep sea between these islands and Sulawesi.The research team also examined the accounts of historic collectors such as Sir Alfred Wallace, and sought to focus on parts of Wallacea that had received the least coverage by historic collectors, as these areas would hold the highest promise of harbouring undescribed avian diversity.The islands that the team targeted were characterised by such incomplete historic coverage: Taliabu and its neighbours, together forming the Sula group, were only briefly visited by eight historic collecting expeditions, all of which remained in coastal areas and failed to penetrate the highlands of the interior because of poor accessibility; and Peleng and the remaining islands of the Banggai group were visited along their coastline by only three historic collectors who never ventured far uphill into the interior.Assoc Prof Rheindt and his team undertook extensive fieldwork in the three remote islands for six weeks, from November 2013 to January 2014, and collected 10 new, long-overlooked avian forms.By integrating genomic and phenotypic research methodologies, the team successfully described five new songbird species and five new subspecies:"Studying the routes and operations of historic collecting expeditions and identifying gaps has been a fruitful approach to pinpoint focal areas in our case. The description of this many bird species from such a geographically limited area is a rarity," shared Assoc Prof Rheindt.He added, "Going forward, the use of earth-history and bathymetric information could also be applied to other terrestrial organisms and regions beyond the Indonesian Archipelago to identify promising islands that potentially harbour new taxa to be uncovered."During the expedition, the research team found that both Taliabu and Peleng have suffered from rampant forest destruction. There is virtually no primary lowland forest on both islands, and most highland forests have been impacted by some form of logging or forest fires."While most of the avifauna we described seems to tolerate some form of habitat degradation and is readily detected in secondary forest and edge, some species or subspecies are doubtless threatened by the immense levels of habitat loss on these islands. As such, urgent, long-lasting conservation action is needed for some of the new forms to survive longer than a couple of decades beyond their date of description," said Assoc Prof Rheindt.
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Extinction
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January 9, 2020
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https://www.sciencedaily.com/releases/2020/01/200109160836.htm
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Large 'herbivores of the sea' help keep coral reefs healthy
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Selective fishing can disrupt the delicate balance maintained between corals and algae in embattled Caribbean coral reefs. Removing large parrotfish, which graze on algae like large land mammals graze on grasses, can allow the algae to overtake the corals, with potentially dire consequences for reef health. New experimental research suggests that maintaining a healthy size distribution of parrotfishes in a sea floor ecosystem through smart fishing practices could help maintain reefs that are already facing decline due to climate change.
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A paper describing the research by scientists at Penn State and the University of California, Santa Barbara appears online in the journal "Coral reefs are incredibly beautiful and intrinsically valuable, but they also protect thousands of miles of coastline and provide habitat for astonishing biodiversity that is the major source of protein for nearly a billion people worldwide," said Andrew A. Shantz, Eberly Research Postdoctoral Fellow at Penn State and the first author of the paper. "Understanding how fishing impacts coral ecosystems will help us to protect this invaluable resource."The researchers used survey data on parrotfish populations from 282 sites across the Caribbean and compared these sites to protected reefs in the Florida Keys to assess how parrotfish populations are impacted by fishing. Surprisingly, the biomass -- the total mass of parrotfish in a region -- was not impacted by fishing. Instead the distribution of fish sizes changed. Fishing selectively removes large parrotfish, but the biomass is maintained because many more small parrotfish are able to occupy the region."Because biomass remained basically the same in regions where there is heavy fishing, we were interested to see if different sized fish played different ecological roles," said Shantz. "We set up an experiment where we could exclude larger fish from accessing an area to see how changes in the distribution of fish sizes impacted corals and their relationship with algae."The experiment involved three different enclosures with different sized openings placed on the sea floor around corals in the protected Florida Keys. One enclosure allowed access to fish of any size, the second excluded only the largest parrotfish, and the third excluded large and medium sized parrotfish."We found that by excluding large parrotfish, the algae grew four times faster," said Shantz. "By excluding both large and medium parrotfish, the algae grew ten times faster. So even though fishing does not reduce the biomass of the fish, it's the larger fish that keep the algae at bay. Unless we can develop and implement fishing strategies that maintain a healthy distribution of fish sizes -- for example, a slot based system with both minimum and maximum size restrictions -- the corals in these regions are at risk."
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Extinction
| 2,020 |
January 7, 2020
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https://www.sciencedaily.com/releases/2020/01/200107104919.htm
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The growing pains of orphan chimpanzees
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The prolonged periods of juvenility and nutritional dependence that are characteristic of human development are thought to facilitate brain and somatic growth in children, as well as provide opportunities to learn and accumulate skills required for a productive adult life. In chimpanzees, the benefits of continuing to associate with mothers after becoming nutritionally independent are less well understood.
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To address this, the researchers used a dataset comprising 18 years of research effort on three groups of wild chimpanzees at the Taï Forest, Côte d'Ivoire, to examine the effects of maternal loss and mothers' social status on offspring lean muscle mass development. "We assessed the muscle mass of 70 offspring from 41 mothers by means of urinary creatinine concentrations, a by-product of metabolic activity in muscles," explains Tobias Deschner, a researcher at the MPI for Evolutionary Anthropology. As expected, offspring muscle mass increased with age in both males and females. However, chimpanzee offspring that lost their mother after they were already weaned had less muscle mass than those with living mothers. Furthermore, mothers of high social status measured by dominance rank, produced offspring with higher muscle mass.This study demonstrates how maternal presence and maternal social status can impact offspring phenotype in wild chimpanzees. Importantly, even once offspring are nutritionally independent, maternal loss has negative consequences on their growth. "Our results emphasize the crucial role of mothers and suggest that even in the absence of consistent direct provisioning from mothers to offspring, chimpanzee mothers still indirectly influence food consumption in their offspring," Liran Samuni, one of the two first authors on the study, points out."This may occur in similar ways to humans," suggests Patrick Tkaczynski, the other first author on the study. "Mothers may provide support to their offspring during competitive interactions with others, and increase their chance to 'win' conflicts, or soften reactions of offspring to challenging situations. Also, mothers may provide opportunities for offspring to learn how to find and access hard to extract or rare food items.""Our study provides evidence that a mother-offspring association and dependence that lasts beyond the weaning age, although unique in its duration and level of investment in human societies, may be a trait with deep evolutionary origins that we share with one of our closest living relatives," declares Catherine Crockford, head of the ERC project group Ape Attachement and senior author of the study.
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Extinction
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January 2, 2020
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https://www.sciencedaily.com/releases/2020/01/200102143354.htm
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Starry eyes on the reef: Color-changing brittle stars can see
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Scientists have shown for the first time that brittle stars use vision to guide them through vibrant coral reefs, thanks to a neat colour-changing trick.
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The international team, led by researchers at Oxford University Museum of Natural History, described a new mechanism for vision in the red brittle star This species first captured scientific attention more than 30 years ago thanks to its dramatic change in colour between day and night and its strong aversion to light. Recently , researchers demonstrated that Lauren Sumner-Rooney, a research fellow at Oxford University Museum of Natural History who studies unusual visual systems, has been working with "These experiments gave us not only the first evidence that any brittle star is able to 'see'," says Sumner-Rooney, "but only the second known example of vision in any animal lacking eyes." The animals were able to seek out areas of contrast, which the researchers think may mimic structures that could offer shelter from predators. Although it appears that their vision is very coarse, on the crowded tropical reefs disturbed brittle stars never have to look too far to make a dash for the nearest cover.However, an unexpected discovery raised new questions about how this visual system worked. "We were surprised to find that the responses we saw during the day disappeared in animals tested at night, yet the light-sensitive cells still seemed to be active," says Sumner-Rooney.The team set about trying to identify what caused this dramatic shift in behaviour, eliminating possible factors such as loss of motivation and low light intensity making vision too difficult. The one they couldn't rule out was Combining a suite of techniques, the researchers reconstructed digital models of individual light-sensing cells in the two species, with and without "It's a very exciting discovery," explains Sumner-Rooney. "It had been suggested 30 years ago that changing colour might hold the key to light-sensitivity in Although this is the first visual system proposed to work using whole-body colour change, the scientists have also identified potential similarities with a sea urchin, distant relatives of brittle stars. Only one species of sea urchin has 'passed' the same tests for vision, and it also, independently, changes colour in response to light levels. Future work will probe whether this sea urchin, the only other animal in the world known to see without eyes, might be using a similar trick to
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Extinction
| 2,020 |
December 19, 2019
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https://www.sciencedaily.com/releases/2019/12/191219142806.htm
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Biodiversity has substantially changed in one of the largest Mediterranean wetlands
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The Camargue in southern France is widely recognised as one of the largest and most biodiverse wetlands in the Mediterranean region.
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Recent research has now shown that grasshoppers, crickets and locusts, comprising orthopterans, and also dragonflies and amphibians have severely declined since the 1970s. This provides evidence of substantial deterioration of the Camargue ecosystem.Many of the biodiversity changes had previously gone unnoticed, because there has been no systematic biodiversity monitoring for many of the species under study. Researchers now used a new and innovative method based on expert knowledge to identify changes in biodiversity in the study area.During a period of seven months, the researchers managed to gather information on population trends and population abundance for almost 1400 species, and also presence and absence data for more than 1500 species for a total of eight different taxonomic groups."These include amphibians, reptiles, breeding birds, fish, mammals, dragonflies, orthopterans such as crickets and locusts, and vascular plants. This information has allowed us to detect some interesting patterns of change within a period of only 40 years," says post-doctoral researcher Sara Fraixedas, from the Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki.The new methodology has made possible the detection of declines in certain taxa that are associated with land-use changes in the area."Temporary ponds and grasslands reduced in surface area by around 60% between 1942 and 1984. These two habitats have declined the most in the Camargue, and they have been converted into farmland or industrial areas. Amphibians and dragonflies are closely linked to freshwater wetlands, whereas many orthopteran species are associated with grasslands. Therefore, it is likely that the severe degradation of the conservation status of these three groups is related to the loss of those habitats," adds Thomas Galewski, leader of the Biodiversity Monitoring and Assessment project at the Tour du Valat.The study also shows that breeding birds and vascular plants have increased in abundance. Authors attribute the increase in bird populations to conservation and management actions related to the implementation of the EU Birds and Habitats Directives, as well as to the arrival of new bird species to the ecosystem.However, many bird species have disappeared from the Camargue between the 1970s and the 2010s. Especially farmland birds are showing a steep decline since the 1950s. The increase in vascular plants is linked to the introduction of new species, some of the them highly invasive, into the study area.Results suggest that the current protection measures in the Camargue area have failed to protect certain taxa. On the other hand, the observed increase in novel and invasive species and the patterns of increases and declines in different groups reveal important changes in the community structure of the studied taxonomic groups."This may be an indication that the Camargue has undergone significant changes with important implications for local ecosystem functioning," Sara Fraixedas says.
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Extinction
| 2,019 |
December 19, 2019
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https://www.sciencedaily.com/releases/2019/12/191219132907.htm
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Understanding why songbirds choose their homes
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New research by University of Alberta biologists uses a new approach to modelling the populations of six species of songbirds in Canada's boreal forest -- and the results show that standard modeling methods may not be accurately capturing species distribution patterns.
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The study shows that birds of the same species do not necessarily use the same habitats in different parts of the boreal forest, a phenomenon they termed differential habitat selection. They developed habitat models to account for this process to give better estimates of population size and distribution."Knowing how species select habitats differently in different parts of their range is an important first step towards a better understanding of their ecology and how populations will respond to human disturbances and conservation efforts," explained Andrew Crosby, postdoctoral fellow who works with Professor Erin Bayne in the Department of Biological Sciences.The researchers examined nearly 20 years of population data following six boreal songbird species in the Canadian boreal forest, including the Blackburnian warbler, the Black-throated Green warbler, the Brown creeper, the Canada warbler, the Cape May warbler, and the Connecticut warbler. The results clearly show spatial variability in habitat selection within species."Bird populations may not respond to changing environmental conditions the way we expect them to if we assume that habitat selection is the same under all conditions and in all places," said Crosby. "This means that the same management actions will likely have different effects in different places. Policies and management strategies will be much more effective if they are tailored specifically for different regions."The research provides a path forward for improving conservation planning and information for making informed policy decisions and resource allocation.
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Extinction
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December 19, 2019
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https://www.sciencedaily.com/releases/2019/12/191219123852.htm
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How microbes reflect the health of coral reefs
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Microorganisms play important roles in the health and protection of coral reefs, yet exploring these connections can be difficult due to the lack of unspoiled reef systems throughout the global ocean. A collaborative study led by scientists at the Woods Hole Oceanographic Institution (WHOI) and the Centro de Investigaciones Marinas -- Universidad de La Habana (CIM-UH) compared seawater from 25 reefs in Cuba and the U.S. Florida Keys varying in human impact and protection, and found that those with higher microbial diversity and lower concentrations of nutrients and organic carbon -- primarily caused by human activities -- were markedly healthier.
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"Human impacts such as overfishing and pollution lead to changes in reef structure," says WHOI graduate student Laura Weber, lead author of the paper. A healthy reef provides home to a diverse group of marine animals, including herbivores that in turn help control algal growth. "Removal of algae grazers such as herbivorous fish and sea urchins leads to increases in macroalgae, which then leads to increased organic carbon, contributing to the degradation of coral reefs," Weber adds.Researchers sampled seawater from each site and measured nutrients as well as a suite of parameters that offer insights into the microbial community. They found a notable difference between the heavily protected offshore reefs in Cuba and the more impacted nearshore ones in the Florida Keys.Jardines de la Reina (Gardens of the Queen), the largest protected area in the Caribbean, is a complex ecosystem of small islands, mangrove forests, and coral reefs located about 50 miles off the southern coast of Cuba. These highly-protected offshore reefs provide habitat and feeding grounds for large numbers of fish, including top predators like sharks and groupers. Here, researchers found low concentrations of nutrients, and a high abundance of Prochlorococcus -- a photosynthetic bacterium that thrives in low nutrient waters."Cuba does not have large-scale industrialized agriculture or extensive development along most of its coastline," says Patricia González-Díaz, Director of CIM-UH and co-author of the study. "So there is not a lot of nutrient run-off and sedimentation flowing on to the reefs." Additionally, the reefs of Jardines de la Reina may be further buffered from impacts by the mangroves and seagrass meadows that lie between the island of Cuba and the reef system of Jardines de la Reina.Conversely, seawater from the more accessible reefs of Los Canarreos, Cuba -- which are more impacted by humans through subsistence and illegal fishing, tourism, and the diving industry -- and the nearshore reefs in the Florida Keys both contained higher organic carbon and nitrogen concentrations.The study demonstrates that protected and healthier offshore Cuban reefs have lower nutrient and carbon levels, and microbial communities that are more diverse with abundant photosynthetic microbes compared to the more impacted, nearshore reefs of Florida. This work suggests that the offshore nature and highly protected status of reefs in Jardines de la Reina have played a role in keeping these reefs healthy by being far from or minimizing human impacts. These findings may aid resource managers in decision making to protect and restore Caribbean coral reefs in the face of habitat and climate-based change.
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Extinction
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December 17, 2019
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https://www.sciencedaily.com/releases/2019/12/191217123957.htm
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Large carnivores and zoos -- essential for biodiversity conservation marketing
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Large carnivores (e.g. bears, big cats, wolves and elephant seals) and zoos should be utilised as powerful catalysts for public engagement with nature and pro-environmental behaviour, suggests a paper published in the scholarly open-access journal
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The paper, which offers a synthesis of contributions, presented at the symposium "Large carnivores and zoos as catalysts for biodiversity conservation: how do we engage the public in the protection of biodiversity?" at the 5th European Congress for Conservation Biology (ECCB), Finland 2018, highlights the wide-reaching influence of the institutions visited by over 700 million people a year worldwide and combining knowledge with emotions and social values. Bringing together natural and social sciences, as well as psychology and education, it provides a rich multifaceted approach to the conservation of biodiversity by exploring the connections between people, large carnivores and zoos."[Zoos] may provide a space where field conservation and human dimensions can combine to foster a commitment between people, from all backgrounds, and the rest of the living world, and break down key barriers to biodiversity conservation, catalysed by the charismatic keystone species housed within their facilities," concludes the team.According to the scientists, large carnivores are essential to engage the public in the urgent need to arrest biodiversity loss due to the many links between wild predators and enhanced biodiversity. They acknowledge that the interactions between people and carnivores are complex and can give rise to conflicts such as concerns related to fears for own safety, fear of loss of other favoured species, material interests, or socio-economic tensions formed by an urban-rural divide.Due to continuous changes in land use, areas of healthy habitat and protected areas are usually small and fragmented and cannot sustain wild carnivores, the paper explains, so it is necessary to coexist with large carnivores. Large carnivores show capabilities to adapt to different human-dominated ecosystems across the world which supports the idea that separation is not a necessary condition for large carnivore conservation. The bigger challenge remains whether human societies can accept and adapt to non-predator-free landscapes."Considering that the occurrence of predator attacks on humans is rare, tolerance of risks is affected by norms, culture, spiritual beliefs, cognitive and emotional factors, including risk perception," elaborated the specialists and added that, "[p]eople's progressive amnesia of what the landscapes were like before large carnivores disappeared may result in acceptance of natural spaces devoid of carnivore species."Research also points to the lack of interest in nature and reduced commitment to biodiversity conservation as being linked cognitive elements such as misconceptions and negative messages about wildlife in formative years and declining opportunities to engage with nature from childhood. This phenomenon has been described as the extinction of experience."Support for the conservation of large carnivores and for biodiversity is more likely when people have an emotional appreciation for diverse species, not just understanding. Both aspects are likely to be enhanced by direct experiences, such as visits to zoos and aquariums that provide an increasingly important opportunity for contact with other species," add the scientists.Recognising the role of zoos as a catalyst for conservation for their contributions in skills and expertise that span animal care and husbandry, public engagement, education and research, is vital for biodiversity conservation. Though education programmes based on knowledge gain are not enough to change people's perceptions, opportunities for emotional engagement and reduction of fear, combined with social context provided by the zoo are great assets in promoting tolerance of large carnivores and biodiversity among visitors who are typically estranged from the wildlife.
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Extinction
| 2,019 |
December 16, 2019
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https://www.sciencedaily.com/releases/2019/12/191216122404.htm
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Limiting the loss of nature
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With only about half of Earth's terrestrial surface remaining as natural vegetation, a University of Queensland-led team has proposed an international goal to halt its continued loss.
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The team, led by Professor Martine Maron, examined how a global goal of 'no net loss' of natural ecosystems could work, where some nations seek net increases in over-depleted natural vegetation, while recognising that for others, limited further losses of ecosystems might be unavoidable."Across the globe, our natural habitats are suffering, with alarming impacts on biodiversity, the climate and other critical natural systems -- impacts that affect people too," Professor Maron said."To stop the loss, there have been calls for global policy-makers to set targets to protect the nature we have left."It's a lofty goal, but for it to be achievable, it needs to be equitable."And that means recognising that some nations might need to contribute more to conservation and restoration than others."The researchers calculated the depletion of natural ecosystems in 170 countries and considered the socioeconomic factors at play in each."There is plenty of divergence across the world," Professor Maron said."Many countries have already converted the vast majority of their natural ecosystems, so ecosystem restoration might be needed to contribute equitably to a global 'no net loss' goal."On the other hand, there are some countries with largely intact remaining ecosystems and urgent human development imperatives, which may need to accept limited and controlled depletion."The latter include some of the world's poorest countries, so finding a way for essential development to proceed without locking in the current ongoing declines of natural ecosystems is critical.A global goal of no net loss could allow this kind of development in an equitable, limited and transparent way."The team's work on a global no net loss goal comes at a critical time, with the UN's Convention on Biological Diversity due for a fresh Global Biodiversity Framework in 2020."Now's the time to work out what we really want a future Earth to look like, and soon our governments will be collectively deciding just that," Professor Maron said."Loss without limit is the paradigm under which natural ecosystems are currently being destroyed -- this needs to stop."We need a strong, overarching goal to retain, restore and protect natural ecosystems, while dramatically increasing conservation ambitions globally."A global NNL goal sets a limit to the loss we -- and biodiversity -- can tolerate, while allowing for human development where it is most urgently needed."
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Extinction
| 2,019 |
December 16, 2019
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https://www.sciencedaily.com/releases/2019/12/191216094515.htm
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Fossil shells reveal both global mercury contamination and warming when dinosaurs perished
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The impact of an asteroid or comet is acknowledged as the principal cause of the mass extinction that killed off most dinosaurs and about three-quarters of the planet's plant and animal species 66 million years ago.
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But massive volcanic eruptions in India may also have contributed to the extinctions. Scientists have long debated the significance of the Deccan Traps eruptions, which began before the impact and lasted, on and off, for nearly a million years, punctuated by the impact event.Now, a University of Michigan-led geochemical analysis of fossil marine mollusk shells from around the globe is providing new insights into both the climate response and environmental mercury contamination at the time of the Deccan Traps volcanism.From the same shell specimens, the researchers found what appears to be a global signal of both abrupt ocean warming and distinctly elevated mercury concentrations. Volcanoes are the largest natural source of mercury entering the atmosphere.The dual chemical fingerprints begin before the impact event and align with the onset of the Deccan Traps eruptions.When the researchers compared the mercury levels from the ancient shells to concentrations in freshwater clam shells collected at a present-day site of industrial mercury pollution in Virginia's Shenandoah Valley, the levels were roughly equivalent.Evidence from the study, which is scheduled for publication Dec.16 in the journal "For the first time, we can provide insights into the distinct climatic and environmental impacts of Deccan Traps volcanism by analyzing a single material," said Kyle Meyer, lead author of the new study. "It was incredibly surprising to see that the exact same samples where marine temperatures showed an abrupt warming signal also exhibited the highest mercury concentrations, and that these concentrations were of similar magnitude to a site of significant modern industrial mercury contamination."Meyer conducted the study as part of his doctoral dissertation in the U-M Department of Earth and Environmental Sciences. He is now a postdoctoral researcher at Portland State University in Oregon.Mercury is a toxic trace metal that poses a health threat to humans, fish and wildlife. Human-generated sources of mercury include coal-fired power plants and artisanal gold mines. At Virginia's South River industrially contaminated site, where the researchers collected freshwater clam shells, signs warn residents not to eat fish from the river."The modern site has a fishing ban for humans because of high mercury levels. So, imagine the environmental impact of having this level of mercury contamination globally for tens to hundreds of thousands of years," said U-M geochemist and study co-author Sierra Petersen, who was Meyer's co-adviser.The researchers hypothesized that the fossilized shells of mollusks, principally bivalves such as oysters and clams, could simultaneously record both coastal marine temperature responses and varying mercury signals associated with the release of massive amounts of heat-trapping carbon dioxide and mercury from the Deccan Traps.The long-lived Deccan Traps eruptions formed much of western India and were centered on the time of the Cretaceous-Paleogene (K-Pg) mass extinction, 66 million years ago.The study used fossil shells collected in Antarctica, the United States (Alabama, Alaska, California and Washington), Argentina, India, Egypt, Libya and Sweden. The researchers analyzed the isotopic composition of the shell carbonate to determine marine temperatures, using a recently developed technique called carbonate clumped isotope paleothermometry.They also measured the amount of mercury in the remarkably well-preserved fossil shells and assembled the first-ever deep-time record of mercury preserved in fossilized biomineral remains.In previous studies, records of environmental mercury have been reconstructed from marine sediments, providing insights into the timing and scale of the Deccan Traps event. But those records lacked such a direct linkage to the climate response. In the new study, both signals are present in the same specimens -- an important first, according to the authors."Mercury anomalies had been documented in sediments but never before in shells. Having the ability to reconstruct both climate and a volcanism indicator in the exact same materials helps us circumvent lots of problems related to relative dating," said Petersen, an assistant professor in the U-M Department of Earth and Environmental Sciences. "So, one of the big firsts in this study is the technical proof of concept."The new technique is expected to have broad applications for the study of mass extinctions and climate perturbations in the geological record, according to the researchers.
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Extinction
| 2,019 |
December 13, 2019
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https://www.sciencedaily.com/releases/2019/12/191213142424.htm
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Why are giant pandas born so tiny?
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Born pink, blind, and helpless, giant pandas typically weigh about 100 grams at birth -- the equivalent of a stick of butter. Their mothers are 900 times more massive than that.
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This unusual size difference has left researchers puzzled for years. With a few exceptions among animals such as echidnas and kangaroos, no other mammal newborns are so tiny relative to their mothers. No one knows why, but a Duke University study of bones across 10 species of bears and other animals finds that some of the current theories don't hold up.Duke biology professor Kathleen Smith and her former student Peishu Li published their findings this month in the Baby panda skeletons are hard to come by, but the researchers were able to study the preserved remains of baby pandas born at the Smithsonian's National Zoo in Washington, D.C.The National Zoo's first panda couple, Ling-Ling and Hsing-Hsing, had five full-term cubs in the 1980s, but none of them survived long after birth.The researchers took micro-CT scans of two of those cubs, along with newborn grizzlies, sloth bears, polar bears, dogs, a fox, and other closely related animals from the Smithsonian National Museum of Natural History and the North Carolina State College of Veterinary Medicine.They used the scans to create 3-D digital models of each baby's bony interior at birth.As a baby animal grows and develops inside the womb, its bones and teeth do, too. The researchers examined the degree of ossification, or how much the skeleton has formed by the time of birth. They looked at whether the teeth had started to calcify or erupt, and the degree of fusion between the bony plates that make up the skull.The panda may be an extreme example, but all bears have disproportionately small babies, Li said. A newborn polar bear's birthweight as a fraction of mom's is less than 1:400, or less than one-half of one percent of her body mass. For the vast majority of baby mammals, including humans, the average is closer to 1:26.One decades-old idea links low birthweights in bears to the fact that, for some species, pregnancy overlaps with winter hibernation. Pregnant females don't eat or drink during this time, relying mostly on their fat reserves to survive, but also breaking down muscle to supply protein to the fetus.The thinking is that, energetically, females can only afford to nourish their babies this way for so long before this tissue breakdown threatens their health. By cutting pregnancy short and giving birth to small, immature babies, bears would shift more of their growth to outside the womb, where babies can live off their mother's fat-rich milk instead of depleting her muscles.Proponents of the theory concede that not all bears -- including pandas -- hibernate during the winter. But the idea is that small birthweight is 'locked in' to the bear family tree, preventing non-hibernating relatives from evolving bigger babies too."It's certainly an appealing hypothesis," Smith said.But the Duke team's research shows this scenario is unlikely. The researchers didn't find any significant differences in bone growth between hibernating bears and their counterparts that stay active year-round and don't fast during pregnancy.In fact, despite being small, the researchers found that most bear skeletons are just as mature at birth as their close animal cousins.The panda bear is the one exception to this rule, results show. Even in a full-term baby panda, the bones look a lot like those of a beagle puppy delivered several weeks premature."That would be like a 28-week human fetus" at the beginning of the third trimester, Smith said.Other factors might have pushed panda babies toward smaller sizes over time -- some researchers blame their bamboo-only diet -- but data are scarce, Li said. The researchers say the panda bear's embryonic appearance likely has to do with a quirk of panda pregnancy.All bears experience what's called "delayed implantation." After the egg is fertilized, the future fetus enters a state of suspended animation, floating in the womb for several months before implanting in the uterine wall to resume its development and get ready for birth.But while other bears gestate for two months after implantation, giant pandas are done in a month."They're basically undercooked," said Li, now a Ph.D. student at the University of Chicago.The researchers say they only looked at skeletons in this study, and it could be that other organs like the brain tell a different story. But the new study suggests that baby pandas follow the same trajectory as other mammal relatives -- their bones mature in the same sequence and at similar rates -- but on a truncated timetable."Development is just cut short," Smith said.Scientists are still searching for a complete explanation of why the panda's peculiar size differential evolved over geological time, and how."We really need more information about their ecology and reproduction in the wild," Smith said, and we may not have much time given their risk of extinction. But this study brings them one step closer to an answer.This research was supported by a Shared Material Instrumentation Facility Undergraduate User Program grant, the Duke Department of Biology, and the Undergraduate Research Office at Duke.
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Extinction
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December 12, 2019
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https://www.sciencedaily.com/releases/2019/12/191212104632.htm
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Harnessing nature's defences against tsunamis
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As sea levels rise and adverse weather events become more common, vulnerable coastal communities are at increasing risk of devastation from storm surges and tsunamis. The death toll from tsunamis, at 260,000 during the past century, was higher than that from any other natural hazard. An international research team led by the University of Göttingen has now compared the effects of human-made and ecosystem protection to propose a hybrid approach including mangroves and coral reefs in coastal protection plans for tropical biodiversity hotspots. The results were published in the journal
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In this study, led by Dr Thomas Wanger at the Agroecology Group at the University of Göttingen, an international team of scientists from Germany, China, Indonesia, Australia, and Singapore evaluated the ways coastal communities can be protected against disaster. The scientists compared conventional engineering solutions such as giant sea walls, with ecological solutions such as mangroves and coral reefs. They evaluated the effectiveness, cost, and the capacity to sustain biodiversity and ecosystems. The research provides new insights about the implementation of improving ecosystem-based coastal protection.Palu in Indonesia has long been home to collaborative research centres led by the University of Göttingen. In 2018, Palu was destroyed by a major tsunami and so the Indonesian government implemented a coastal protection plan. The international research team has worked to improve the existing plan by applying their new findings. In addition, the team proposed to use the city of Palu as a case study to further investigate how ecological factors can mitigate the dangers for coastal communities globally."In the future, ecosystem-based protection should form the basis to plan a coastal protection strategy. Improving this strategy through human-made and engineered solutions may make the entire endeavour more cost-efficient and may better protect valuable coastal biodiversity and related ecosystem services," says Wanger. "If the international research community can monitor such a hybrid 'ecosystem-based and engineered' approach in Palu, the 'Palu Model' could become an important learning opportunity for other high risk coastal hazard sites in tropical biodiversity hotspots." he adds.
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Extinction
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December 11, 2019
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https://www.sciencedaily.com/releases/2019/12/191211145711.htm
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Paleontology: Experiments in evolution
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A new find from Patagonia sheds light on the evolution of large predatory dinosaurs. Features of the 8-m long specimen from the Middle Jurassic suggest that it records a phase of rapid diversification and evolutionary experimentation.
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In life, it must have been an intimidating sight. The dimensions of the newly discovered dinosaur fossil suggest that this individual was up to 8 meters long, and its skull alone measured 80 centimeters from front to back. The specimen was uncovered by the Munich paleontologist Oliver Rauhut in Patagonia, and can be assigned to the tetanurans -- the most prominent group of bipedal dinosaurs, which includes such iconic representatives as Allosaurus, Tyrannosaurus and Velociraptor. This is also the group from which modern birds are derived. The new find is the most complete dinosaur skeleton yet discovered from the early phase of the Middle Jurassic, and is between 174 and 168 million years old. The specimen represents a previously unknown genus, and Rauhut and his Argentinian colleague Diego Pol have named it Asfaltoventor vialidadi. The genus name includes both Greek and Latin components (including the Latin term for hunter), while also referring to the nature of the deposits in which the fossil was found and the species name honours the road maintance of Chubut, who helped in the recovery of the specimen.Almost the entire skull is preserved, together with the complete vertebral column including parts of the pelvis, all the bones of both anterior extremities and parts of the legs. "The fossil displays a very unusual combination of skeletal characters, which is difficult to reconcile with the currently accepted picture of the relationships between the three large groups that comprise the tetanurans -- Megalosauria, Allosauria and Coelurosauria," says Rauhut, who is Professor of Palaeontology in the Department of Earth and Environmental Sciences at Ludwig-Maximilians-Universitaet (LMU) in Munich and Senior Curator of the Bavarian State Collection for Paleontology and Geology. He and his co-author Diego Pol, who is based in the Museo Paleontológico Egidio Feruglio in Trelew (Argentina), describe the find in a paper that appears in the online journal The unusual mixture of morphological features displayed by A. vialidadi prompted the authors to carry out a comparative analysis with other tetanurans. They noted that around the period to which the new find can be assigned, the geographical range of this group was rapidly expanding, while the different species developed very similar sets of skeletal features.Rauhut links the explosive evolution of the group with an episode of mass extinction that had occurred in the late stage of the Lower Jurassic, about 180 million years ago. The two researchers therefore interpret the parallel development of similar external traits in different species as an example of evolutionary experimentation during the subsequent rapid expansion and diversification of the tetanurans. The prior extinction of potential competitors will have opened up new ecological niches for the groups that survived, and the tetanurans were apparently among those that benefited."This is a pattern that we also observe in many other groups of animals in the aftermath of mass extinctions. It holds, for example, for the expansion and diversification of both mammals and birds following the extinction of the dinosaurs at the end of the Cretaceous 66 million years ago," says Rauhut. It could also explain why it is so difficult to unravel the phylogenetic relationships close to the origin of many highly diversified animal groups.
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Extinction
| 2,019 |
December 11, 2019
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https://www.sciencedaily.com/releases/2019/12/191211145632.htm
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Earth was stressed before dinosaur extinction
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New evidence gleaned from Antarctic seashells confirms that Earth was already unstable before the asteroid impact that wiped out the dinosaurs.
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The study, led by researchers at Northwestern University, is the first to measure the calcium isotope composition of fossilized clam and snail shells, which date back to the Cretaceous-Paleogene mass extinction event. The researchers found that -- in the run-up to the extinction event -- the shells' chemistry shifted in response to a surge of carbon in the oceans.This carbon influx was likely due to long-term eruptions from the Deccan Traps, a 200,000-square-mile volcanic province located in modern India. During the years leading up to the asteroid impact, the Deccan Traps spewed massive amounts of carbon dioxide (CO"Our data suggest that the environment was changing before the asteroid impact," said Benjamin Linzmeier, the study's first author. "Those changes appear to correlate with the eruption of the Deccan Traps.""The Earth was clearly under stress before the major mass extinction event," said Andrew D. Jacobson, a senior author of the paper. "The asteroid impact coincides with pre-existing carbon cycle instability. But that doesn't mean we have answers to what actually caused the extinction."The study will be published in the January 2020 issue of the journal Jacobson is a professor of Earth and planetary sciences in Northwestern's Weinberg College of Arts and Sciences. Linzmeier was a postdoctoral researcher with the Ubben Program for Climate and Carbon Science at the Institute for Sustainability and Energy at Northwestern when the research was conducted. He is now a postdoctoral fellow at the University of Wisconsin-Madison in the Department of Geoscience.Previous studies have explored the potential effects of the Deccan Traps eruptions on the mass extinction event, but many have examined bulk sediments and used different chemical tracers. By focusing on a specific organism, the researchers gained a more precise, higher-resolution record of the ocean's chemistry."Shells grow quickly and change with water chemistry," Linzmeier said. "Because they live for such a short period of time, each shell is a short, preserved snapshot of the ocean's chemistry."Seashells mostly are composed of calcium carbonate, the same mineral found in chalk, limestone and some antacid tablets. Carbon dioxide in water dissolves calcium carbonate. During the formation of the shells, COFor this study, the researchers examined shells collected from the Lopez de Bertodano Formation, a well-preserved, fossil-rich area on the west side of Seymour Island in Antarctica. They analyzed the shells' calcium isotope compositions using a state-of-the-art technique developed in Jacobson's laboratory at Northwestern. The method involves dissolving shell samples to separate calcium from various other elements, followed by analysis with a mass spectrometer."We can measure calcium isotope variations with high precision," Jacobson said. "And those isotope variations are like fingerprints to help us understand what happened."Using this method, the team found surprising information."We expected to see some changes in the shells' composition, but we were surprised by how quickly the changes occurred," Linzmeier said. "We also were surprised that we didn't see more change associated with the extinction horizon itself."The researchers said that understanding how the Earth responded to past extreme warming and CO"To some degree, we think that ancient ocean acidification events are good analogs for what's happening now with anthropogenic COBrad Sageman and Matthew Hurtgen, both professors of Earth and planetary sciences at Northwestern, are co-senior authors of the paper.The study, "Calcium isotope evidence for environmental variability before and across the Cretaceous-Paleogene mass extinction," was supported by the Ubben Program for Climate and Carbon Science at Northwestern University, the David and Lucile Packard Foundation (award number 2007-31757) and the National Science Foundation (award numbers EAR-0723151, ANT-1341729, ANT-0739541 and ANT-0739432.
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Extinction
| 2,019 |
December 9, 2019
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https://www.sciencedaily.com/releases/2019/12/191209193422.htm
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When penguins ruled after dinosaurs died
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What waddled on land but swam supremely in subtropical seas more than 60 million years ago, after the dinosaurs were wiped out on sea and land?
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Fossil records show giant human-sized penguins flew through Southern Hemisphere waters -- along side smaller forms, similar in size to some species that live in Antarctica today.Now the newly described It lived between 62.5 million and 60 million years ago at a time when there was no ice cap at the South Pole and the seas around New Zealand were tropical or subtropical.Flinders University PhD palaeontology candidate and University of Canterbury graduate Jacob Blokland made the discovery after studying fossil skeletons collected from Chatham Island between 2006 and 2011.He helped build a picture of an ancient penguin that bridges a gap between extinct giant penguins and their modern relatives."Next to its colossal human-sized cousins, including the recently described monster penguin "Kupoupou also had proportionally shorter legs than some other early fossil penguins. In this respect, it was more like the penguins of today, meaning it would have waddled on land."This penguin is the first that has modern proportions both in terms of its size and in its hind limb and foot bones (the tarsometatarsus) or foot shape."As published in the US journal The discovery may even link the origins of penguins themselves to the eastern region of New Zealand -- from the Chatham Island archipelago to the eastern coast of the South Island, where other most ancient penguin fossils have been found, 800km away.University of Canterbury adjunct Professor Scofield, Senior Curator of Natural History at the Canterbury Museum in Christchurch, says the paper provides further support for the theory that penguins rapidly evolved shortly after the period when dinosaurs still walked the land and giant marine reptiles swam in the sea."We think it's likely that the ancestors of penguins diverged from the lineage leading to their closest living relatives -- such as albatross and petrels -- during the Late Cretaceous period, and then many different species sprang up after the dinosaurs were wiped out," Professor Scofield says"It's not impossible that penguins lost the ability to fly and gained the ability to swim after the extinction event of 66 million years ago, implying the birds underwent huge changes in a very short time. If we ever find a penguin fossil from the Cretaceous period, we'll know for sure."BACKGROUND: The new species is based on the fossilised bones of five partial skeletons. Another two specimens showed a second larger penguin species was also present on the main Chatham Island but there was not enough material to formally name it. All of the described skeletons were collected between 2006 and 2011 by a group led by Monash University palaeontologist Jeffrey Stilwell. Dr Alan Tennyson from Te Papa Tongarewa the Museum of New Zealand and Professor Julia Clark from University of Texas at Austin were in the group and are also-coauthors of the paper. The species is named after Associate Professor Stilwell with all specimens now cared for by Te Papa.
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Extinction
| 2,019 |
December 5, 2019
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https://www.sciencedaily.com/releases/2019/12/191205141752.htm
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Dull teeth, long skulls, specialized bites evolved in unrelated plant-eating dinosaurs
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Herbivorous dinosaurs evolved many times during the 180 million-year Mesozoic era, and while they didn't all evolve to chew, swallow, and digest their food in the same way, a few specific strategies appeared time and time again. An investigation of the skulls of 160 non-avian dinosaurs revealed the evolution of common traits in the skulls and teeth of plant-eating members of otherwise very different families of these extinct reptiles. These new examples of convergent evolution in plant-eating dinosaurs appear December 5 in the journal
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"People often think of dinosaurs as a swansong for extinction or that they were a failed species. But they were actually extremely successful in terms of how different species' anatomies evolved -- particularly in herbivores," says co-senior author David J. Button (@ItsDavidButton), a paleontologist at the Natural History Museum, London.By looking at herbivorous and carnivorous dinosaur skulls, Button and co-senior author Lindsay Zanno, a professor at North Carolina State University and the head of paleontology at the North Carolina Museum of Natural Sciences, found that while there are many ways for dinosaurs that eat similar foods to evolve, some traits reappear during evolution, even in unrelated species.Herbivorous dinosaurs came in all shapes and sizes. Some exhibited dull, flat teeth like horses, while others had beaked faces like tortoises; some developed towering necks like giraffes, while others mimicked the short and stout build of a rhino. "Nonetheless, we see the evolution of common traits in the skull between these otherwise very different herbivorous dinosaur groups," explains Button."For example, both the ostrich-like ornithomimosaurs and giant titanosaurs independently evolved elongate skulls and weaker bites, whereas the horned ceratopsians and gazelle-like ornithopods sported more powerful jaws and grinding teeth," he says. These are results of convergent evolution, where adaptation to a diet of plants led to the evolution of common characters in different dinosaur groups.The researchers hypothesized that some traits would be most common in plant-eaters. Slow-moving dinosaurs with small heads and dull teeth would likely have a difficult time wrapping their jaws around the neck of another dinosaur, in the way a carnivore like the Tyrannosaurus is thought to have done with ease. Instead, eating plants poses other challenges, such as grinding down tough plant stems."There's a tradeoff between biting speed and biting efficiency," says Button. "If you're a herbivorous animal, you don't really need speed because plants don't move very fast."Some of the results of this functional analysis surprised the researchers, however. That was the case when investigating the eating habits of ankylosaurs, armored, armadillo-like plant-eating dinosaurs with small teeth and a large stomach cavity. Researchers previously thought dinosaurs with these traits usually swallowed their food nearly whole and let their gut break it down. "In our results, we found that ankylosaurs actually may have chewed their food more thoroughly than is often thought. So, that was interesting," says Button.In the future, Button and Zanno hope to look at the entire skeleton of herbivorous dinosaurs for similar, reoccurring traits. They also plan to expand this work to better understand predominate traits in carnivores, though Button admits plant-eaters will always be his favorite dinosaurs to study."People think that carnivorous dinosaurs are super exciting and cool because they run fast, and kill stuff," he says. "But I think the plant-eating dinosaurs evolved in much more interesting and sophisticated ways. That's what makes this work so exciting."
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Extinction
| 2,019 |
December 5, 2019
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https://www.sciencedaily.com/releases/2019/12/191205091452.htm
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Changing wildfires in the California's Sierra Nevada may threaten northern goshawks
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Wildfire is a natural process in the forests of the western US, and many species have evolved to tolerate, if not benefit from it. But wildfire is changing. Research in the journal
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How Northern Goshawks respond to fire is not well understood. The single study to date examined the effects of fire on nest placement and found that the birds avoided nesting in areas burned at high severity. The effects of fire on the birds' roosting and foraging habitat however may be more complex, because prey populations may temporarily increase in burned areas and improve their quality as a foraging habitat."To effectively manage and conserve wildlife, we need to understand how animals use the landscape across their life cycle," noted corresponding author Dr. Rachel Blakey at The Institute for Bird Populations and UCLA La Kretz Center for California Conservation Science.Dr. Blakey and her colleagues at the institute wanted to better understand the habitat preferences of Northern Goshawks. In collaboration with scientists at the US Forest Service and the US Geological Survey Missouri Cooperative Fish and Wildlife Research Unit at the University of Missouri, the research team looked specifically at how goshawks use burned areas in the Plumas National Forest, California.Twenty Goshawks were fitted with solar-powered global positioning system (GPS) tracking devices that monitored the habitats the goshawks chose for foraging and night-time roosting. Goshawks preferred forest stands with larger, more mature trees and higher canopy cover-also called "late seral" forest-for both roosting and foraging."While there was individual and sex-based variability in selection of habitat at the finest scales, at the larger spatial scales that are arguably most important for management, goshawks consistently selected for late-seral forest," added Dr. Blakey.Unfortunately, late-seral forest is already in short supply in the western US and the attributes that make it attractive to Northern Goshawks also put it at a high risk of large and severe wildfires. Further analysis of the study area showed that 80 percent foraging habitat and 87 percent of roost sites were designated a "High Wildfire Potential Hazard" by the US Forest Service.Rodney Siegel, Executive Director of The Institute for Bird Populations and co-author of the study said "A lot of work by our organization and others over the past decade has shown that some wildlife species are quite resilient to forest fire and can even thrive in recently burned forests."But habitat selection by the Northern Goshawks we studied suggests that these birds, with their strong preference for late seral forest attributes like big trees and closed forest canopy, are jeopardized by changing fire patterns that reduce forest cover," added Dr. Siegel.Dr. Siegel also notes that reducing wildfire risk in goshawk habitat will be a major challenge for forest managers. "The treatments to reduce risk of high-severity fire, including forest thinning and prescribed fire, may also reduce goshawk foraging and roosting habitat quality if they decrease canopy cover and fragment late-seral forest," said Dr. Siegel.Dr. Blakey expects that the foraging and roosting habitat preferences seen in goshawks in this study are probably common to goshawks throughout the Sierra Nevada region, and perhaps western montane forests in general. Likewise, this preferred habitat is likely at risk of high severity fire across the region as well."Given that fire regimes are changing across the range of the Northern Goshawk, both in the US and across the species' distribution globally, the use of burned habitats by this species should also be investigated more broadly," concluded Dr. Blakey.
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Extinction
| 2,019 |
December 3, 2019
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https://www.sciencedaily.com/releases/2019/12/191203145200.htm
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For some corals, meals can come with a side of microplastics
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Tiny microplastic particles are about as common in the ocean today as plastic is in our daily lives.
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Synthetic clothing, containers, bottles, plastic bags and cosmetics all degrade and release microplastics into the environment. Corals and other marine organisms are eating microplastics that enter the waterway. Studies in this emerging field show some harmful effects, but it's largely unknown how this ubiquitous material is impacting ocean life.A new experiment by the University of Washington has found that some corals are more likely to eat microplastics when they are consuming other food, yet microplastics alone are undesirable. Two coral species tested responded differently to the synthetic material, suggesting variations in how corals are adapting to life with microplastics. The study was published Dec. 3 in the journal "The more plastic we use, the more microplastics there are, and the more corals are going to be exposed," said lead author Jeremy Axworthy, a UW doctoral student in the School of Aquatic and Fishery Sciences. "Our study found that some corals probably won't eat microplastics and will keep going about their daily business. But some might -- and if they happen to be sensitive to warmer ocean temperatures or other stressors, this is just another compounding factor to be worried about."Corals are tiny animals that are rooted to the reef or rocks on the ocean floor. They use tentacle-like arms to sweep food into their mouths. Many rely on algae for energy, but most also consume drifting animals for survival.This study is the first to examine whether corals eat microplastics when exposed to warmer water, which is expected to accelerate with climate change. Rising ocean temperatures can be deadly for coral: warm water stresses them, causing corals to lose their symbiotic algae partner that undergoes photosynthesis and provides energy for them to survive. When this happens, coral bleaching and eventual death can occur.But some corals have adapted to bleaching by shifting their diets to feed on tiny marine organisms called zooplankton, which provide an alternate energy source. As they munch on these small animals -- often the same size as microplastics -- the research team wondered whether they also were ingesting plastic fragments.The experiment shows corals do eat microplastics when they switch to a zooplankton diet, adding one more stressor for corals in a changing ocean environment."Microplastics are not as simple as a life-or-death threat for corals -- it's not that black or white," said senior author Jacqueline Padilla-Gamiño, assistant professor at the UW School of Aquatic and Fishery Sciences. "It's about total energy lost. If corals constantly are dealing with microplastics, it might not kill them, but there will be less energy for them to grow and to reproduce."The researchers collected two species of common corals off the east coast of Oahu, Hawaii, and exposed half of each species to warmer water for several weeks to induce stress and bleaching. Then they ran four different feeding experiments on both bleached and non-bleached corals: corals were fed only microplastics; only a type of zooplankton; microplastics and zooplankton; or nothing.After dissecting the coral polyps, researchers found that corals stressed by warmer temperatures actually ate much less than their counterparts in normal seawater. This was unexpected and possibly due to stress from high water temperatures. However, one of the two species, known for its voracious eating habits in the wild, consumed microplastics only while also eating zooplankton. Neither coral species ate microplastics alone.The researchers don't know why one species of coral readily ate microplastics in the presence of other food, but avoided microplastics when they were the only thing on the menu. They suspect that this species of coral can read certain chemical or physical cues from the plastics and the prey, but might not be able to distinguish between the two when both are present.It's also possible the plastic used in this experiment is less desirable to corals, and that plastics with a different chemical makeup could, in fact, be tasty to corals. The researchers plan to test the "tastiness" of other types of microplastics, such as synthetic fibers from clothing.Ultimately, some coral species likely face greater risks from exposure to microplastics than others, the study found. The researchers will look next at impacts on the physiology of corals that are exposed over a longer period to microplastics."Knowing that will provide a lot more context to this work," Axworthy said. "We need to know the full physiological impacts of chronic exposure to microplastics on corals, especially at increased temperatures, to understand how serious the problem is."In the meantime, the problem of microplastics isn't going away. A 2014 estimate found between 15 and 51 trillion microplastic particles in the oceans, and plastic waste entering the oceans is expected to increase tenfold between 2010 and 2025."It's important when talking about waste management to think big picture -- what are we putting in the oceans?" Padilla-Gamiño said. "We don't know where plastic goes, where it stays, who grabs it, and what are the mechanisms by which we get it back. We are just at the tip of understanding these implications."
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Extinction
| 2,019 |
December 2, 2019
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https://www.sciencedaily.com/releases/2019/12/191202081641.htm
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When reefs die, parrotfish thrive
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In contrast to most other species, reef-dwelling parrotfish populations boom in the wake of severe coral bleaching.
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The surprise finding came when researchers led by Perth-based Dr Brett Taylor of the Australian Institute of Marine Science (AIMS) looked at fish populations in severely bleached areas of two reefs -- the Great Barrier Reef in the western Pacific and the Chagos Archipelago in the Indian Ocean.The sites are 8000 kilometres apart.Bleaching is coral's stress reaction to prolonged exposure to higher sea surface temperatures."Warming oceans place enormous pressure on reefs and if the temperatures remain high for too long the coral will die. The more frequently this occurs there is less time for coral reefs to recover," Dr Taylor said.In the damaged areas of the reefs, the study found that parrotfish populations increased in number by between two and eight times, and individual fish were about 20% larger than those in unbleached sections.Almost every other species of fish was in sharp decline in the bleached areas.Parrotfish, named because of their tightly packed teeth in a beak formation, use their teeth to scrape microorganisms off coral -- and their presence in large numbers on damaged reefs very likely helps the process of repair, Taylor and his colleagues suggest."When bleaching reduces coral cover on the reefs, it creates large areas of newly barren surfaces," Taylor said."This immediately gets colonised by the microalgae and cyanobacteria, basically an internal and external layer of 'scunge', which provides nutritious, abundant food for parrotfish."The researchers concluded that the coral and the parrotfish constitute a feedback loop, slowly bringing each other into balance. When reefs are damaged, parrotfish numbers swell. This results in low levels of scunge, giving the coral the best chance to recover. As the reef then returns to health, parrotfish numbers decline again."We found reef ecosystems in two different oceans had the same response to global heat events which is indicative of the current magnitude of climate change effects," he said.The fact that plump parrotfish were found in large numbers on both reefs indicates the feedback loop is an inherent part of reef ecology and not caused by local factors."Parrotfish are a vital link in the reef ecosystem," says AIMS co-author Dr Mark Meekan."As herbivores, their grazing shapes the structure of reefs through effects on coral growth and suppression of algae that would otherwise proliferate. Because of these important ecological roles, they have been described as 'ecosystem engineers' of reef systems."As well as AIMS, scientists working on the project came from James Cook University in Australia, the University of Auckland in New Zealand, and the University of Lancaster in the UK.
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Extinction
| 2,019 |
November 30, 2019
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https://www.sciencedaily.com/releases/2019/11/191130092054.htm
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Sounds of the past give new hope for coral reef restoration
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Young fish can be drawn to degraded coral reefs by loudspeakers playing the sounds of healthy reefs, according to new research published today in
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An international team of scientists from the UK's University of Exeter and University of Bristol, and Australia's James Cook University and Australian Institute of Marine Science, say this "acoustic enrichment" could be a valuable tool in helping to restore damaged coral reefs.Working on Australia's recently devastated Great Barrier Reef, the scientists placed underwater loudspeakers playing healthy reef recordings in patches of dead coral and found twice as many fish arrived -- and stayed -- compared to equivalent patches where no sound was played."Fish are crucial for coral reefs to function as healthy ecosystems," said lead author Tim Gordon, of the University of Exeter."Boosting fish populations in this way could help to kick-start natural recovery processes, counteracting the damage we're seeing on many coral reefs around the world."This new technique works by regenerating the sounds that are lost when reefs are quietened by degradation."Healthy coral reefs are remarkably noisy places -- the crackle of snapping shrimp and the whoops and grunts of fish combine to form a dazzling biological soundscape. Juvenile fish home in on these sounds when they're looking for a place to settle," said senior author Professor Steve Simpson, also of the University of Exeter."Reefs become ghostly quiet when they are degraded, as the shrimps and fish disappear, but by using loudspeakers to restore this lost soundscape, we can attract young fish back again.Australian Institute of Marine Science fish biologist Dr Mark Meekan added: "Of course, attracting fish to a dead reef won't bring it back to life automatically, but recovery is underpinned by fish that clean the reef and create space for corals to regrow."The study found that broadcasting healthy reef sound doubled the total number of fish arriving onto experimental patches of reef habitat, as well as increasing the number of species present by 50%.This diversity included species from all sections of the food web -- herbivores, detritivores, planktivores and predatory piscivores.Different groups of fish provide different functions on coral reefs, meaning an abundant and diverse fish population is an important factor in maintaining a healthy ecosystem.Professor Andy Radford, a co-author from the University of Bristol, said: "Acoustic enrichment is a promising technique for management on a local basis."If combined with habitat restoration and other conservation measures, rebuilding fish communities in this manner might accelerate ecosystem recovery."However, we still need to tackle a host of other threats including climate change, overfishing and water pollution in order to protect these fragile ecosystems."Gordon added: "Whilst attracting more fish won't save coral reefs on its own, new techniques like this give us more tools in the fight to save these precious and vulnerable ecosystems."From local management innovations to international political action, we need meaningful progress at all levels to paint a better future for reefs worldwide."
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Extinction
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December 2, 2019
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https://www.sciencedaily.com/releases/2019/12/191202102057.htm
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Operational mapping system for high-resolution tropical forest carbon emissions
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For the first time, scientists have developed a method to monitor carbon emissions from tropical forests at an unprecedented level of detail. The approach will provide the basis for developing a rapid and cost-effective operational carbon monitoring system, making it possible to quantify the economic cost of deforestation as forests are converted from carbon sinks to sources. The study was published in
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Researchers at the Arizona State University Center for Global Discovery and Conservation Science (GDCS) worked with satellite imagery from Planet Inc., an earth-imaging company based in San Francisco, to develop maps of carbon stocks and emissions for Peru by combining millions of hectares of airborne laser measurements of canopy height with thousands of high resolution Planet Dove satellite images."We combined advanced remote sensing data and machine learning algorithms to estimate aboveground carbon stocks and emissions throughout the highly diverse ecosystems of Peru. Our approach will serve as a transformative tool to quantify and monitor climate change mitigation services provided by tropical forests," said Ovidiu Csillik, lead author of the study.Using this technology, the researchers were able to estimate a total of 6.9 billion metric tons of carbon stored aboveground in Peru's diverse ecosystems, of which only 2.9 billion tons are found in protected areas. However, they also found that between 2012 and 2017, 80 million metric tons of new carbon were sequestered above ground in forests, but another 96 million tons were emitted via logging, deforestation and other factors. This resulted in a net loss of forest carbon in the five-year study period.The new high-resolution monitoring approach revealed the precise location of these carbon emissions, for example, in areas converted from forest to oil palm and cacao plantations, agricultural and urban areas, and gold mining."Our study powerfully demonstrates a new capability to not only measure forest carbon stocks from space, but far more critically, to monitor changes in carbon emissions generated by a huge range of activities in forests," said Greg Asner, director of GDCS and co-author of the study. "The days of mapping forests based simply on standing carbon stocks are behind us now. We are focused on carbon emissions, and that's precisely what is needed to mitigate biodiversity loss and climate change."
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Extinction
| 2,019 |
November 26, 2019
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https://www.sciencedaily.com/releases/2019/11/191126121215.htm
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Did human hunting activities alone drive great auks' extinction?
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New insight on the extinction history of a flightless seabird that vanished from the shores of the North Atlantic during the 19th century has been published today in
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The findings suggest that intense hunting by humans could have caused the rapid extinction of the great auk, showing how even species that exist in large and widespread populations can be vulnerable to exploitation.Great auks were large, flightless diving birds thought to have existed in the millions. They were distributed around the North Atlantic, with breeding colonies along the east coast of North America and especially on the islands off Newfoundland. They could also be found on islands off the coasts of Iceland and Scotland, as well as throughout Scandinavia.But these birds had a long history of being hunted by humans. They were poached for their meat and eggs during prehistoric times, and this activity was further intensified in 1500 AD by European seamen visiting the fishing grounds of Newfoundland. Their feathers later became highly sought after in the 1700s, contributing further to their demise."Despite the well-documented history of exploitation since the 16th century, it is unclear whether hunting alone could have been responsible for the species' extinction, or whether the birds were already in decline due to natural environmental changes," says lead author Jessica Thomas, who completed the work as part of her PhD studies at Bangor University, UK, and the University of Copenhagen, Denmark, and is now a postdoctoral researcher at Swansea University, Wales, UK.To investigate this further, Thomas and her collaborators carried out combined analyses of ancient genetic data, GPS-based ocean current data, and population viability - a process that looks at the probability of a population going extinct within a given number of years. They sequenced complete mitochondrial genomes of 41 individuals from across the species' geographic range and used their analyses to reconstruct the birds' population structure and dynamics throughout the Holocene period, the last 11,700 years of Earth's history."Taken together, our data don't suggest that great auks were at risk of extinction prior to intensive human hunting behaviour in the early 16th century," explains co-senior author Thomas Gilbert, Professor of Evolutionary Genomics at the University of Copenhagen. "But critically, this doesn't mean that we've provided solid evidence that humans alone were the cause of great auk extinction. What we have demonstrated is that human hunting pressure was likely to have caused extinction even if the birds weren't already under threat from environmental changes."Gilbert adds that their conclusions are limited by a couple of factors. The mitochondrial genome represents only a single genetic marker and, due to limited sample preservation and availability, the study sample size of 41 is relatively small for population genetic analyses."Despite these limitations, the findings help reveal how industrial-scale commercial exploitation of natural resources have the potential to drive an abundant, wide-ranging and genetically diverse species to extinction within a short period of time," says collaborator Gary Carvalho, Professor in Zoology (Molecular Ecology) at Bangor University. This echoes the conclusions of a previous study* on the passenger pigeon, a bird that existed in significant numbers before going extinct in the early 20th century."Our work also emphasises the need to thoroughly monitor commercially harvested species, particularly in poorly researched environments such as our oceans," concludes co-senior author Michael Knapp, Senior Lecturer in Biological Anthropology and Rutherford Discovery Fellow at the University of Otago, New Zealand. "This will help lay the platform for sustainable ecosystems and ensure more effective conservation efforts."
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Extinction
| 2,019 |
November 18, 2019
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https://www.sciencedaily.com/releases/2019/11/191118115348.htm
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Saving 'half Earth' for nature would affect over a billion people
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As the extinction crisis escalates, and protest movements grow, some are calling for hugely ambitious conservation targets. Among the most prominent is sparing 50% of the Earth's surface for nature.
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'Half Earth' and similar proposals have gained traction with conservationists and policy makers. However, little work has gone into identifying the social and economic implications for people.Now, researchers have produced the first attempt to assess how many and who would be affected if half the planet was 'saved' in a way that secures the diversity of the world's habitats.A team of scientists analysed global datasets to determine where conservation status could be added to provide 50% protection to every "ecoregion": large areas of distinct habitats such as Central African mangroves and Baltic mixed forests.Even avoiding where possible "human footprints" such as cities and farmland, their findings suggest a "conservative" estimate for those directly affected by Half Earth would be over one billion people, primarily in middle-income countries.Many wealthy and densely populated nations in the Global North would also need to see major expansions of land with conservation status to reach 50% -- this could even include parts of London, for example.The study's authors, led by University of Cambridge researchers, say that while radical action is urgently required for the future of life on Earth, issues of environmental justice and human wellbeing should be at the forefront of the conservation movement."People are the cause of the extinction crisis, but they are also the solution," said Dr Judith Schleicher, who led the new study, published today in the journal Towards the end of next year, the leaders of most of the world's nations will aim to agree global targets for the future of conservation at the Convention on Biological Diversity in Beijing."Goals that emerge from the Convention on Biological Diversity could define conservation for a generation," said Schleicher, who conducted the research while at the University of Cambridge's Conservation Research Institute and its Department of Geography."We need to be ambitious given the environmental crises. But it is vital that social and economic implications at local levels are considered if the drivers of biodiversity loss are to be tackled. The lives of many people and the existence of diverse species hang in the balance."The idea of a 'Half Earth' for nature was popularised by famed biologist E.O. Wilson in his 2017 book of the same name. More recently, a 'Global Deal for Nature' -- aiming for 30% protection by 2030 and 50% by 2050 -- has been endorsed by a number of leading environmental organisations. However, these proposals have been ambiguous about "exact forms and location," say Schleicher and colleagues.Based on their analyses, researchers cautiously estimate that an additional 760 million people would find themselves living in areas with new conservation status: a fourfold increase of the 247 million who currently reside inside protected areas.The team call for proponents of Half Earth, and all supporters of area-based conservation, to "recognise and take seriously" the human consequences -- both negative and positive -- of their proposals."Living in areas rich in natural habitat can boost mental health and wellbeing. In some cases, protected areas can provide new jobs and income through ecotourism and sustainable production," said Schleicher."However, at the other extreme, certain forms of 'fortress' conservation can see people displaced from their ancestral home and denied access to resources they rely on for their survival."While conservation coverage has been increasing, species numbers continue to plummet -- suggesting a "disconnect" between international targets and implementation at local and regional levels, argue the team."Conservation needs strong action to protect life on earth, but this must be done in a way that takes account of people and their needs," said co-author Dr Chris Sandbrook from Cambridge's Department of Geography."Failing to consider social issues will lead to conservation policy that is harmful to human wellbeing and less likely to be implemented in the first place."Conservation is not just a problem for people of the Global South. Recent reports on UK wildlife revealed devastating declines in iconic species. Yet the study reveals that achieving 50% ecoregion coverage could even see parts of central London become protected. "It highlights the absurdity of hitting arbitrary targets," Sandbrook said.
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Extinction
| 2,019 |
November 14, 2019
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https://www.sciencedaily.com/releases/2019/11/191114154458.htm
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Researchers explore how citizens can become agents of environmental change
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If you like to walk in the woods, raft a river, dig in a garden or look at butterflies, you could become an agent of change.
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Science and policy may not be enough to solve complex environmental challenges ranging from species extinction to water pollution, but actively engaged citizens could tip the balance, according to a new Stanford-led study that provides a blueprint for empowering people to turn the tide of environmental destruction. In "Effective environmental education moves people to persistent action through engaging with issues in relevant ways," said study lead author Nicole Ardoin, an associate professor at the Stanford Graduate School of Education and a senior fellow at the Stanford Woods Institute for the Environment. "Without it, making sustained change on environmental and sustainability issues simply is not possible."While the rate of climate change and species extinction intensifies, the U.S. outdoor recreation sector is growing more than one-and-a-half-times faster than the overall economy. Historic federal legislation passed earlier this year is opening more than a million acres of wildlands to public access. Increasingly, nonprofit groups and government agencies are harnessing this growing interest in nature as a force for conserving it. The question for them has been what kinds of activities or educational engagement have the most measurable impact.To get at that question, the researchers analyzed reviews of more than 100 environmental education programs that addressed topics such as habitat protection and restoration, water quality, energy conservation, climate change and recycling. From this, the researchers gleaned four keys to maximizing the chance that programs will help citizens make meaningful environmental impacts: focus on locally relevant issues; collaborate with experts; incorporate action-oriented learning strategies and approaches, such as hands-on experiments and policy recommendations; and measure outcomes.The researchers point to citizen science as an example of the four principles at work. At its best, citizen science involves members of the general public participating in aspects of science initiatives from design to implementation. Their hands-on engagement in the conservation effort yields reliable, usable data. These initiatives provide community members with avenues for collecting and measuring local-scale data, working directly with scientists and research managers on relevant research and documenting outcomes.Incorporating the study's findings into new environmental education programs could help more conservation organizations and agencies involve the public effectively in improving environmental quality. It could also help cyclists, river rafters, hikers and others contribute directly to the nature they enjoy.Environmental education: Keys to successExample: Students in a reforestation project created nurseries, improved their abilities to serve as custodians, and participated in plantings on school grounds, as well as in other deforested parts of the community, with the goal of reconnecting with local ecosystems and enhancing student capabilities to serve as custodians.2) Collaborate with scientists and resource managersExample: A program brought together prison inmates with scientists, students and natural area managers to encourage lifelong learning, support ecological research and promote habitat restoration through plant production and captive rearing of animals in correctional facilities. Conservation practitioners provided the knowledge that resulted in raising and releasing approximately 550 frogs, 4,000 butterflies and 1 million plants.3) Incorporate action elements into programsExample: University students' sea turtle research and habitat assessment resulted in a proposal to the Mexican government for a marine protected area, with recommendations for fishing activity zones for resource and ecotourism uses.4) Measure and report program outcomesExample: Researchers in a reforestation education initiative reported not only the number of trees planted but also provided data on the survival rates of planted trees.Study co-authors include researchers from Virginia Tech and 4Research. The North American Association for Environmental Education funded the research through its eeWORKS initiative, a collaboration among nonprofit organizations and government agencies.Ardoin is also director of the Emmett Interdisciplinary Program in Environment and Resources (E-IPER) in the School of Earth, Energy & Environmental Sciences (Stanford Earth).
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Extinction
| 2,019 |
November 13, 2019
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https://www.sciencedaily.com/releases/2019/11/191113153053.htm
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Extinct giant ape directly linked to the living orangutan
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By using ancient protein sequencing, researchers have retrieved genetic information from a 1.9 million year old extinct, giant primate that used to live in a subtropical area in southern China. The genetic information allows the researchers to uncover the evolutionary position of
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It is the first time that genetic material this old has been retrieved from a warm, humid environment. The study is published in the scientific journal 'Primates are relatively close to humans, evolutionary speaking. With this study, we show that we can use protein sequencing to retrieve ancient genetic information from primates living in subtropical areas even when the fossil is two million years old. Until now, it has only been possible to retrieve genetic information from up to 10,000-year-old fossils in warm, humid areas. This is interesting, because ancient remains of the supposed ancestors of our species, Today, scientists know that the human and the chimpanzee lineages split around seven or eight million years ago. With the previous methodologies though, they could only retrieve human genetic information not older than 400,000 years. The new results show the possibility to extend the genetic reconstruction of the evolutionary relationships between our species and extinct ones further back in time, at least up to two million years -- covering a much larger portion of the entire human evolution.In a recent study, also published on 'By sequencing proteins retrieved from dental enamel about two million years old, we showed it is possible to confidently reconstruct the evolutionary relationships of animal species that went extinct too far away in time for their DNA to survive till now. In this study, we can even conclude that the lineages of orangutan and Sequencing protein remains two million years old was made possible by stretching to its limits the technology at the base of proteomic discovery: mass spectrometry. State of the art mass spectrometers and the top palaeoproteomics expertise needed to get the best out of such sophisticated instrumentation are key resources deriving from the decade-long strategic collaboration with Jesper Velgaard Olsen, Professor at Novo Nordisk Foundation Center for Protein Research and co-author on this study.The fossil evidence attributed to 'Previous attempts to understand which could be the living organism most similar to The study of human evolution by palaeoproteomics will continue in the next years through the recently established "Palaeoproteomics to Unleash Studies on Human History (PUSHH)" Marie Sk?odowska Curie European Training Network (ETN) Programme.The research is funded mainly by VILLUM FONDEN, the Novo Nordisk Foundation, and the Marie Sklowowska-Curie Actions Individual Fellowship and International Training Network programmes.
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Extinction
| 2,019 |
November 13, 2019
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https://www.sciencedaily.com/releases/2019/11/191113092557.htm
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Healthy mangroves help coral reef fisheries under climate stress
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Healthy mangroves can help fight the consequences of climate change on coral reef fisheries, according to a University of Queensland-led study.
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UQ's Professor Peter Mumby said corals have been bleached and reefs have lost their structural complexity as a major consequence of warming seas."Many people are worried that -- due to climate change -- reef fishery yields could halve if coral reefs flatten, losing the hiding places that support thousands of fish," he said."When a young fish arrives at a degraded reef it has nowhere to hide and is easily targeted by predators."Of course, predators experience the same problem when they're young, so the entire food web becomes unproductive and few fish survive."Despite the alarming trend, the team found mangroves provided a partial solution."We know that many reef fish can use mangroves as an alternative nursery habitat to the reef," Professor Mumby said."Mangroves provide a calm, safe environment with plenty of food and allow fish to grow larger before heading out to the reef as adults."In fact, we discovered that these nurseries could support fisheries productivity that is equal to that in complex reefs that lack nurseries."The researchers from UQ, the ARC Centre of Excellence for Coral Reef Studies and Victoria University of Wellington, compared and validated model predictions with field data from Belize.Victoria University's Dr Alice Rogers said the results should inform reef fisheries management strategies to protect areas now and into the future."Mangrove nurseries essentially allow some fish to sidestep the challenges of early life on a degraded reef," she said."These fish then benefit by finding it relatively easy to find food because it has few places to hide."Mangrove restoration can be important, but in places where that's impossible, future research might examine adapting structures to offer mangrove-like nursery functions."This would be in environments that either do not support natural mangrove forests or have too large a tidal range to provide stable nursery functions in coastal fringes."Professor Mumby said the protection and restoration of mangrove habitats should remain a priority."While we need to take every effort to prevent reef degradation, our study reveals that healthy mangrove forests can help buffer the effects of habitat loss on reef fisheries."It's critical that they need to remain a priority as part of the battle to mitigate climate change impacts on coral reefs and their functioning."Ultimately, we need to protect intact combinations of mangroves and coral reefs."
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Extinction
| 2,019 |
November 12, 2019
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https://www.sciencedaily.com/releases/2019/11/191112110347.htm
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Applying biodiversity conservation research in practice
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The world's population is growing -- and with it the need for natural resources. This calls for consistent action to protect biodiversity. "The rapidly ongoing extinction of numerous animal and plant species threatens the health of our environment, as well as valuable resources and services linked to our well-being," says Bea Maas of the Department of Botany and Biodiversity Research. Despite comprehensive scientific evidence and solutions, there is often a lack of practical implementation. "There is a misconception among many scientists that if enough evidence is generated and put in the hands of policy-makers, the problem will be solved," says co-lead author and co-editor Anne Toomey of Pace University. "But we know from behavioral science that translating research into practice is not quite that simple."
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A current collection of 14 articles in the journal In their article, Maas, Toomey and Loyola examine three central questions: Are we currently setting the right priorities in conservation science? Are we documenting and learning from our mistakes and failures through evaluation? And: How can we better consider different perspectives in our decisions?The publication deals with these questions from different perspectives. It includes three global reviews on the role of environmental education, technology applications and failure documentation in conservation, as well as case studies and perspectives on issues such as impact evaluation, data use, cost planning, experience analysis and the influence of different government systems on biodiversity conservation.According to Maas and co-authors, simple answers cannot be found. However, the researchers agree on one point, as Maas emphasises: "Conservation researchers must learn to better navigate the spaces between research and implementation. The key to this lies in a timely and improved cooperation between conservation-relevant science, politics and practice."
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Extinction
| 2,019 |
November 11, 2019
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https://www.sciencedaily.com/releases/2019/11/191111084933.htm
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Gimme shelter: Seven new leech species call freshwater mussels home
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The frequent presence of leeches with a hidden lifestyle in the mantle cavity of freshwater mussels has been recorded since the second half of the 19th century. Yet this was, until now, regarded as an accidental phenomenon. Recent research not only reveals seven mussel-associated leech species new to science, but also shows that their association evolved over millions of years.
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The diverse ecological group of leeches were found inside more than 3,000 freshwater mussels collected (by numerous collaborators) from East Asia, Southeast Asia, India and Nepal, Africa and North America between 2002 and 2018. Arthur Bogan, Research Curator of Mollusks for the North Carolina Museum of Natural Sciences, was part of the massive collecting effort and focused his search on parts of eastern Russia (Vladivostok area), Japan and Myanmar.The study's novel data reveals that at least two groups of mussel-associated leech species could be considered obligate inhabitants of the mantle cavity of freshwater mussels, meaning they cannot complete their lifecycle without exploiting their host. How did this come about? According to lead author Ivan N. Bolotov of the Federal Center for Integrated Arctic Research of the Russian Academy of Sciences, "It has been suggested that the primary selective pressure driving the evolution of parental care in leeches may have been predation on leech eggs and juvenile stages. From this point of view, [this lifestyle] could be considered a progressive evolutionary trait in brooding behavior helping to protect juvenile stages from predators."To estimate divergence times for mussel-associated leech clades, we calculated the first fossil-calibrated global phylogeny of leeches using a fossil leech cocoon from mid-Triassic lacustrine deposits in Antarctica as a calibration. It was found that leeches are slowly evolving animals as several other 'living fossil' taxa, for example freshwater mussels, coelacanths, anthozoans, sturgeons and puddle fishes. The reliable mutation rates obtained by us are of great importance to future evolutionary studies of these worms."The study also showed that even these leech species are not permanent residents. Molecular studies of the digestive system content of the adult mussel-associated leeches indicate that they leave their mussel hosts periodically to obtain blood of freshwater fishes. Probably, adult leeches need to use one or several higher-calorie fish blood meals instead of nutritionally sparse mussel haemolymph (body fluids of invertebrates) to ensure the successful development of eggs and complete their life cycle. While larvae and juvenile mussel-associated leeches could feed on mucus and body fluids of freshwater mussels.Such a two-host feeding behavior, when fish blood meals are needed at the final stage of the lifecycle just before leech reproduction, appears to be a successful adaptation to a freshwater environment, in which availability of vertebrate blood is limited, and many leech species are forced to use nutrient-poor haemolymph as the primary feeding source.The discovery of this mussel-leech association has wider ranging importance because freshwater mussels are one of the most imperiled animal groups worldwide, revealing the fastest rates of extinction. Habitat degradation, river pollution and climate change are the primary causes of global decline. However, biological threats for freshwater mussels are still poorly known.The findings were published in
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Extinction
| 2,019 |
November 8, 2019
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https://www.sciencedaily.com/releases/2019/11/191108102854.htm
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Conservation scientists call for reverse to biodiversity loss
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A group of international conservationists is urging governments across the globe to adopt a new approach to address the impact of economic development on the natural world.
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Renowned researchers, including University of Queensland scientists, aim to draw attention to what they call "net positive outcomes for nature."Professor James Watson, of UQ and the Wildlife Conservation Society, said the new approach rejected the idea that biodiversity loss was an inevitable consequence of economic development."This new net positive approach is underpinned by the concept of a conservation hierarchy, which provides a framework for structuring biodiversity conservation actions based on how they contribute to worldwide conservation," he said."We're calling for more ambitious, proactive measures to ensure greater benefits to the natural environment are achieved in concert with development activities."Conservation actions should be based on how they contribute to our shared overall vision for the natural world, rather than piecemeal actions to protect species or habitats."We need policymakers to seriously and urgently prioritise the reduction of development impacts as they happen, retain and restore habitats proactively, and enhance the prospects for nature everywhere."The framework would allow the whole range of conservation efforts to be tracked at a global level, whether they are implemented by national governments, indigenous groups, businesses or private individuals."This allows for more consistent, comprehensive and informative evaluation of the progress we are collectively making toward restoring nature," Professor Watson said."Our approach is much more ambitious than current policy commitments, which typically relate only to location-specific impacts, particular species trends or certain sectors of the economy."It outlines how the global community can move to a position in which economic development activities would be integrated with, rather than in opposition to, positive biodiversity outcomes."The conservationists are calling for a shift in the language and approach to global conservation policy discussions in advance of next year's UN Convention on Biological Diversity, which will be held in China and will set the strategic plan for biodiversity for the next decade and to 2050."It's obvious that nature is running out of time, and nations have one last chance to get a bold target in place to halt the declines and extinctions that are now commonplace across the world," Professor Watson said."A headline goal that calls for a net gain for nature, will make it possible for governments and industry to work hand in hand to avert biodiversity crisis."
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Extinction
| 2,019 |
November 4, 2019
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https://www.sciencedaily.com/releases/2019/11/191104121621.htm
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Global policy-makers must take a more ambitious approach to reversing biodiversity loss
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A group of leading conservationists, including Dr Joseph W. Bull at the University of Kent, is urging governments across the globe to adopt a new approach to address the impact of economic development on our natural world.
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In a new paper, published by This new net positive approach is underpinned by the concept of a Conservation Hierarchy, which provides a framework for structuring biodiversity conservation actions based on how they contribute to our shared overall vision for our natural world. The Hierarchy would allow for the proactive, strategic consideration of conservation actions -- shifting our focus away from more reactive piecemeal actions to protect species or habitats. It seeks to extend the focus of conservation efforts beyond increasing the number of designated protected areas, to also focus on reducing the impact of development as it happens, retaining and restoring habitats proactively, and enhancing the prospects for nature everywhere.The framework would allow the whole range of conservation efforts to be tracked at a global level, whether they are implemented by national governments, indigenous groups, businesses or private individuals. This then provides for more consistent, comprehensive and informative evaluation of the progress we are collectively making towards restoring nature.The Conservation Hierarchy is more ambitious than current policy commitments, which typically relate only to location-specific impacts, particular species trends or certain sectors of the economy. It outlines how the global community can move to a position in which economic development activities would be integrated with, rather than in opposition to, positive biodiversity outcomes.The conservationists are calling for a shift in the language and approach to global conservation policy discussions in advance of next year's UN Convention on Biological Diversity, which will be held in China and will set the strategic plan for biodiversity for the next decade and on to 2050. They argue that nations adopting a headline target of net positive outcomes for biodiversity would have major implications for the way that conservation is delivered and encourage greater engagement with nature conservation around the world.The research was led by Dr Joseph W. Bull, Senior Lecturer in Conservation Science at Kent's Durrell Institute of Conservation and Ecology. He worked with professors EJ Milner-Gulland (University of Oxford) and James Watson (University of Queensland and Wildlife Conservation Society), as well as additional co-authors to produce the report, including collaborators from several major international conservation organisations, such as the World Wildlife Fund.Dr Bull said: 'The loss of native species and habitats is a pattern that is being repeated in gardens, farmlands, wildlands, rivers and oceans across the planet. The current focus on protecting what nature remains is not nearly enough. We must find ways to not only halt, but also to reverse, biodiversity loss. We should be going above and beyond our current actions to seek conservation gains wherever possible.'Professor Milner-Gulland said: 'The world must take the leap from a focus on actions that prevent biodiversity loss, and instead adopt a proactive approach to restoring nature. The Conservation Hierarchy provides the underpinning for the truly ambitious action which the public are demanding, to achieve a sustainable, wild and socially-just world.'Professor Watson said: 'It is obvious that nature is running out of time, and nations have one last chance to get a bold target in place to halt the declines and extinctions that are now commonplace across the world. Only with a bold headline goal that calls for a net gain for nature, will it be possible for governments and industry to work hand in hand to avert the biodiversity crisis.'
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Extinction
| 2,019 |
October 30, 2019
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https://www.sciencedaily.com/releases/2019/10/191030151145.htm
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Carbon bomb: Study says climate impact from loss of intact tropical forests grossly underreported
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A new study in the journal
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The study calculates new figures relating to intact tropical forest lost between 2000-2013 that show a staggering increase of 626 percent in the long-term net carbon impacts through 2050. The revised total equals two years' worth of all global land-use change emissions.The authors of the study, from WCS, University of Queensland, University of Oxford, Zoological Society of London, World Resources Institute, University of Maryland, and University of Northern British Columbia, found that direct clearance of intact tropical forests resulted in just 3.2 percent of gross carbon emissions from all deforestation across the pan-tropics. However, when they factored in full carbon accounting, which considers forgone carbon removals (carbon sequestration that would occur annually into the future if cleared or degraded forest had remained intact after year 2000), selective logging, edge effects and declines of carbon-dense tree species due to overhunting of seed-dispersing animals, they discovered that the figure skyrocketed by a factor of more than six times.Said the study's lead author Sean Maxwell of WCS and the University of Queensland: "Our results revealed that continued destruction of intact tropical forests is a ticking time bomb for carbon emissions. There is an urgent need to safeguard these landscapes because they play an indispensable role in stabilizing the climate."According to 2013 estimates, 549 million acres of intact tropical forests remain. Only 20 percent of tropical forests can be considered "intact," but those areas store some 40 percent of the above-ground carbon found in all tropical forests.The authors say that intact forest retention rarely attracts funding from schemes designed to avoid land-use and land cover change emissions in developing nations.Notably, the Reducing Emissions from Deforestation and Forest Degradation (REDD+) approach enables developing countries to receive financial incentives for enhancing carbon stocks, or avoiding the loss of carbon that would otherwise be emitted due to land-use and land cover change. Among other activities, REDD+ covers support for conservation of forests not under immediate threat, and was formally adopted by parties to the United Nations Framework Convention on Climate Change in 2008 at the 14th Conference of the Parties in Poland. Since then, however, financial support and implementation has predominantly focused on areas with high historical rates of deforestation (i.e. 'deforestation frontiers'). This is widely believed to deliver more immediate and more clearly demonstrable emission reductions than conserving intact forest areas. The latter tend to be treated as negligible sources of emissions as a result of the short timescales and conservative assumptions under which REDD+ operates -- assumptions which the present study suggests are causing key opportunities to be missed.Said WCS's Tom Evans, a co-author of the study: "The relative value of retaining intact tropical forest areas increases if one takes a longer-term view and considers the likely state of the world's forests by mid-century -- a milestone date in the Paris Agreement. Agricultural expansion, logging, infrastructure and fires reduced the global extent of intact forests by 7.2 percent between 2000 and 2013 alone, yet the eventual carbon emissions locked in by these losses have not been comprehensively estimated."The authors go on to say that a comparable analysis is needed for intact forests outside of the tropics such as the boreal forests of Canada and Russia, given that approximately half to two-thirds of carbon removals on earth's intact ecosystems occur outside the tropics. Without this global clean-up service, COSaid co-author James Watson of WCS and the University of Queensland: "Clearly, the climate mitigation potential of retaining intact forests is significant, but without proactive conservation action by national governments, supported by the global community, this potential will continue to dwindle.At least 35 percent of the intact forests studied are home to, and protected by, Indigenous Peoples. Intact forests also provide exceptional levels of many other environmental services -- for example they protect watersheds much better than degraded forests, return moisture to the air that falls in distant regions as rain, and help to keep vast numbers of species safe from extinction. When compared to forests that have been degraded by large-scale human activities, intact forests are more resistant to shocks such as fire and drought and usually less accessible to logging and agriculture conversion, making them one of our best conservation bets in the face of a rapidly changing climate.
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Extinction
| 2,019 |
October 30, 2019
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https://www.sciencedaily.com/releases/2019/10/191030110015.htm
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In Southeast Asia, illegal hunting is a more threat to wildlife than forest degradation
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For decades habitat loss and degradation were considered the important drivers for defaunation in tropical rainforest ecosystems. A new study carried out by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in cooperation with the World Wide Fund for Nature Vietnam (WWF-Vietnam) and the Sabah Forestry Department of the Government of Malaysia suggests that for ground dwelling mammal and bird communities, illegal hunting using indiscriminate snares may be a more immediate threat than forest degradation through selective logging. The researchers conducted a large scale camera-trapping study to compare several forest areas with logging concessions in Malaysian Borneo and protected areas in the Annamites ecoregion of Vietnam and Laos known to be subjected to illegal hunting. The results, published in the journal
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While both habitat degradation and unsustainable hunting have long been known to negatively affect animal communities in tropical rainforests, no study had directly compared how these threats compare in their severity in terms of losses of mammal and bird biodiversity at landscape scales. The result was that both logging and hunting negatively affected ground-dwelling mammal and bird communities, and unsustainable hunting had more severe effects on these communities. Overhunted sites in the Annamite Mountains of Vietnam and Laos had a higher proportion of species extirpated than the degraded sites in Borneo. Even species which persisted in the landscape subjected to illegal hunting had smaller distributions than similar species in the logging concessions."We had a unique opportunity to investigate the complex mechanisms of these defaunation drivers and compare their relative severities," says Andrew Tilker, doctoral student at the Leibniz-IZW and Asian Species Officer at Global Wildlife Conservation, one of the lead authors of the paper. "Our rainforest study sites in Malaysian Borneo are degraded through logging but have experienced little hunting, whereas our rainforest study sites in the Annamite Mountains are structurally intact but are subjected to extremely high illegal hunting pressure. Because the two study landscapes generally have similar habitats and faunal communities, it was an opportunity for us to investigate to what extent these defaunation drivers differ in their impact on tropical rainforest faunal communities.""These findings are not only interesting from an academic perspective, they also have implications for conservation work," says Dr Jesse F. Abrams, postdoc at the Leibniz-IZW and co-first author. "Our results show that maintaining habitat quality as a means of protecting tropical biodiversity is, by itself, insufficient." The researchers suggest that, whilst both defaunation drivers should be addressed to maintain tropical biodiversity, in some cases it may be more prudent to focus limited conservation resources on addressing overhunting rather than habitat degradation.Because hunting in the Annamites is primarily accomplished by the setting of indiscriminate wire snares, the findings of the study have implications for other landscapes in Southeast Asia, which currently are facing an ever-increasing snaring "epidemic." In this respect, the levels of defaunation found in the rainforest study sites in the Annamites by the researchers could offer a foreboding glimpse into the future of biodiversity across the wider Southeast Asian biodiversity hotspot. Co-author Ben Rawson, Conservation Director of WWF-Vietnam, says: "Industrial-scale snaring must be addressed if we are to avoid empty rainforests in the region and retain healthy populations of what are now some of the world's rarest species."The study's findings also have positive implications for conservation. Datuk Mashor Mohd Jaini Director of the Sabah Forestry Department notes, "These results show that logging concessions can be safe havens for mammal and bird communities, particularly if sustainable forest management protocols are applied, following principles of forest certification standards" Dr Andreas Wilting, project leader, agrees. "Incorporating these degraded sites into conservation planning strategies could substantially extend the conservation real estate for the world's tropical regions," he says. "Our study has made it very clear that tropical rainforests must be protected from unsustainable hunting, regardless of whether they are logging concessions or protected areas. We must get ahead of the wave of indiscriminate hunting that is sweeping across Southeast Asia. Only then can we ensure the survival of Southeast Asia's biodiversity heritage."
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Extinction
| 2,019 |
October 30, 2019
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https://www.sciencedaily.com/releases/2019/10/191030073310.htm
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Classic energy theory fails to explain coral distribution across depth
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Coral species richness at different depths is unrelated to energy availability, according to a new study analysing diversity across an Australasian reef.
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Research from James Cook University, Lancaster University, the University of Copenhagen and Queensland University of Technology, published in The research, funded by the Australian Research Council Centre of Excellence Programme, generated an unprecedented dataset of 8,460 coral colonies across six reefs in Kimbe Bay, Papua New Guinea.This allowed the team to conduct a robust test of the drivers that underlie how corals are distributed over depth for the first time, enabling them to test the theory that there will be a greater species diversity where there is greater available energy.For corals, the highest diversity was expected in the shallows because they depend on energy from sunlight. To test this idea, researchers surveyed diversity at depths of between 0 and 45 metres, reaching significantly deeper than most previous surveys, and covering 98 per cent of the light gradient.In contrast to the expectations based on the theory, the research revealed that coral diversity among the team's samples was highest at depths of between 15 and 20 metres.Lead author Dr Edward Roberts, of James Cook University, said: "Our understanding of how coral diversity varies across depth has been limited by a lack of high quality data due to the difficulty of deeper surveys."We were able to overcome that in our survey in Kimbe Bay. This allowed us to test the classic Species Energy hypothesis that proposes the greater the energy available, the greater the diversity, as theoretically more energy allows more individuals to co-exist. This in turn allows more species to maintain large enough populations to avoid local extinction."Our results do not agree with this classic explanation of how diversity changes with energy. Instead, the shallowest depths had fewer species, a pattern also poorly explained by alternative explanations such as competition between corals or environmental disturbance."The results of the research provide cause to find new theories about diversity distribution.Co-author Dr Sally Keith, of Lancaster Environment Centre, said: "Hyper-diverse corals reefs are ideal ecosystems to test theories about how diversity is distributed in nature, so it is really interesting that our results do not support the classic hypotheses.""More broadly, our analyses cast doubt on the suitability of these hypotheses more generally across terrestrial, marine and freshwater systems, suggesting that ecologists might need to rethink the underlying causes of these fundamental patterns of diversity."
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Extinction
| 2,019 |
October 29, 2019
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https://www.sciencedaily.com/releases/2019/10/191029131452.htm
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New insight on how bacteria evolve drug resistance could lead to improved antibiotic therapies
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Researchers have provided new insight into a mechanism behind the evolution of antibiotic resistance in a type of bacterium that causes severe infections in humans.
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Their findings in the multidrug-resistant bacterium Pseudomonas aeruginosa (P. aeruginosa), published today in "Antibiotic resistance is one of the most serious threats to public health worldwide," says first author Camilo Barbosa, formerly a postdoctoral student in senior author Hinrich Schulenburg's lab at the Kiel Evolution Center (KEC) of Kiel University, Germany. "The World Health Organization warns of a post-antibiotic era in which infections can no longer be treated and could become one of the most frequent non-natural causes of death."The rapid evolution of antibiotic resistance makes antibacterial drugs ineffective within short periods of time, which means we need new strategies to maintain or even improve the effectiveness of existing antibiotics. But this development needs to take the relevant evolutionary processes into account, or else new drugs will likely fail."In this study, Barbosa and his colleagues looked into an evolutionary trade-off called collateral sensitivity in P. aeruginosa. Collateral sensitivity occurs when bacteria evolve resistance to one drug but develop increased sensitivity to another drug at the same time."While a variety of distinct cases of collateral sensitivities have previously been described, it was still unclear whether they could be exploited for antibiotic treatment," Barbosa explains. "We tested one key requirement of this principle for medical implementation: stability of the evolutionary trade-off. Is collateral sensitivity stable across time, thereby allowing us to exploit it as a trade-off in order to eliminate bacterial populations and/or prevent emergence of drug resistance?"Their experiments revealed that P. aeruginosa produces distinct cases of evolved collateral sensitivities in response to different drugs. Some of these are generally stable over time, leading to increased population extinction or at least the absence of the evolution of multidrug resistance. The team also found that the effectiveness of drugs was determined by the order in which they were used, the evolutionary costs for the bacteria when evolving antibiotic resistance, and the underlying genetic mechanisms."The pathogen's ability to adapt was particularly constrained when the treatment included a drug change from an aminoglycoside to a beta-lactam, a penicillin-like substance," Barbosa adds. In this case, the bacteria were unable to adapt and went extinct as a result of the sequential administration of the antibiotics. In other drug combinations, however, the pathogens were able to develop new multiple resistances. The evolutionary costs of resistance to the bacteria also played an important role in therapy success."The effects of changing certain drug classes and the impact of evolutionary costs on the development of resistance demonstrate the enormous potential of evolutionary principles for the design of new, sustainable antibiotic therapies," concludes senior author Hinrich Schulenburg, Professor in Zoology at the KEC. "As a next step, we plan to further develop these promising evolution-based strategies so that they may one day be used in patient treatment."
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Extinction
| 2,019 |
October 28, 2019
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https://www.sciencedaily.com/releases/2019/10/191028164338.htm
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Extent of human encroachment into world's protected areas revealed
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A study of human activity within thousands of conservation spaces in over 150 countries suggests that -- on average across the world -- protected areas are not reducing the "anthropogenic pressure" on our most precious natural habitats.
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Protected areas are vital to preserving diverse life on Earth, as well as mitigating climate change by conserving carbon-sequestering vegetation, say Cambridge scientists. They argue that the findings show the effects of chronic underfunding and a lack of involvement of local communities."Rapidly establishing new protected areas to meet global targets without providing sufficient investment and resourcing on the ground is unlikely to halt the unfolding extinction crisis," said lead author Dr Jonas Geldmann from the University of Cambridge Conservation Research Institute.The research, published today in The scientists matched every satellite 'pixel' (64 square kilometres) of each protected area to a local pixel of commensurate soil type, elevation, and so on -- but without conservation status. This allowed researchers to gauge the effect of protected areas when compared to an "appropriate sample" of unprotected land.The majority of protected areas in every global region had suffered increases in human pressure. However, across the Northern Hemisphere and Australia, protection had -- on average -- proved effective at slowing human encroachment when compared with unprotected habitats.In regions such as South America, Sub-Saharan Africa and South-East Asia, home to the world's richest biodiversity as well as some of its poorest communities, pressure from damaging human activity inside protected areas was "significantly higher" on average than in matched areas across fifteen years of data.The researchers found a link between increased human encroachment on protected areas and nations with fewer roads and a lower rank on the Human Development Index."Our study suggests that protected areas in more remote and wild parts of the tropics have experienced alarming increases in human pressure since 1995," said Geldmann. "These places house a disproportionately high amount of the Earth's biodiversity, and play an irreplaceable role in maintaining our most threatened species."Previous studies to compare protected and unprotected land have been limited to forests, and shown that protected areas reduce deforestation. The new research confirms that protected areas are more effective in places like the Amazon, but have struggled to safeguard many other habitats such as savannahs.Rises in human activity were found to be particularly acute in the protected areas of East and Central Africa. In Sub-Saharan grasslands, for example, cropland inside protected areas had increased at almost double the rate seen in matched unprotected land. In African mangroves, pressure from agriculture had increased by around 13% more inside protected areas than outside.While in the remote grassland habitats of South East Asia, agriculture had increased by 8% more in protected areas compared to similar non-protected areas. Likewise, some forested areas in South America, particularly outside the Amazon, saw agricultural encroachment increase around 10% more in protected areas."Our study shows that agriculture is the driving force behind threats to protected areas, particularity in the tropics," said Geldmann. "Our data does not reveal the causes, but we suspect factors that play a major role include rapid population growth, lack of funding, and higher levels of corruption. Additionally, most unprotected land suitable for agriculture is already farmed.""We think that what we are seeing are the effects of establishing protected areas on paper, but not following through with the right funding, management and community engagement that is needed," Geldmann said."Important ambitions to protect 17% of land by the end of this decade, expected to increase to 30% at a pivotal meeting next year in China, will not mean much if not accompanied by enough resources to ensure the preservation of precious habitats."The research team argue that protected area designation can sometimes undermine the rights of local communities, which in turn can end up encouraging over-exploitation and paving the way for opportunistic "outsiders." Other studies have shown that supporting indigenous people to manage reserves themselves can reduce habitat loss.
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Extinction
| 2,019 |
October 28, 2019
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https://www.sciencedaily.com/releases/2019/10/191028104145.htm
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Mutated ferns shed light on ancient mass extinction
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Most researchers believe that the mass extinction 201 million years ago was caused by release of CO
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At the end of the Triassic around 201 million years ago, three out of four species on Earth disappeared. Up until now, scientists believed the cause of the catastrophe to be the onset of large-scale volcanism resulting in abrupt climate change. Now, new research suggest there might be several factors in play.An international research team led by the Geological Survey of Denmark and Greenland (GEUS) show that increased concentrations of the toxic element mercury in the environment contributed to the mass extinction. They recently published their finds in "By looking at fern spores in sediments from the mass extinction, it was evident that these ferns were negatively affected by the mercury levels. Since mercury is accumulated in the food chain, it seems likely that other species have suffered as well," says lead scientist Sofie Lindström."These results suggest that the end-Triassic mass extinction was not just caused by greenhouse gases from volcanoes causing global climate change, but that they also emitted toxins such as mercury wreaking havoc," she says.One of the co-authors of the study, Professor Hamed Sanei from Aarhus University, has previously demonstrated increased mercury levels from volcanism in a Large Igneous Province (LIP) during the most severe mass extinction known, the end-Permian crisis, where perhaps as much as 95% of life on Earth disappeared. Volcanic activity in LIPs is thought to be responsible for four of the five largest mass extinctions during the last 500 million years."Prior to industrialism, volcanic activity was the major release mechanism of large amounts of mercury from the Earth's crust. That makes it possible to use mercury in sediments to trace major volcanic activity in the Earth's past and in extent tie the extinctions of fossil organisms to LIP volcanism," Hamed Sanei explains.Other previous studies have shown elevated mercury concentrations in Triassic-Jurassic boundary sediments over a very large area stretching from Argentina to Greenland and from Nevada to Austria and that made the team curious about the impact on the end-Triassic event."We decided to examine whether mercury could have played a role," Hamed Sanei says.When looking at fern spores from core samples dating from 201 million years ago at the end of the Triassic the team indeed saw a link between increased mercury levels and mutations in the spores."During the mass extinction the mutated spores become increasingly common, and in turn the mutations get more and more severe. In some of my counts I found almost only mutated spores and no normal ones, which is very unusual," Sofie Lindström explains.This rise in mutations happened during a period of increased volcanic activity in a LIP called the Central Atlantic Magmatic Province (CAMP) leading to rising mercury levels. Since mercury is a mutagenic toxin, its' increased distribution from the volcanic activity could help to explain the sudden deterioration of the ecosystem. Therefore, the fern spores could serve as indicators of increased mercury poisoning."This could hint to that the whole food chain might have been negatively affected," says Sofie Lindström.Previous studies have found increased amounts of malformed pollen during the end-Permian mass extinction 252 million years ago, which like the end-Triassic crisis is blamed on volcanism. These studies have suggested that the mutations during the end-Permian crisis were caused by increased UVB radiation, due to thinning of the ozone layer from the volcanism."This could also be a possible explanation for the mutations that we see during the end-Triassic crisis," explains co-author Bas van de Schootbrugge from Utrecht University. "However, in our study we found only low amounts of mutated pollen, and during the end-Permian crisis spores do not appear to exhibit the same types of malformations registered during the end-Triassic mass extinction. This may indicate different causes for the plant mutations at the two events."However, it is important not to lock on to just one cause when looking at a global crisis such as the end-Triassic event, says Sofie Lindström:"Generally, we prefer simple explanations to mass extinctions such as meteorite impacts or climate change, but I don't think it's that simple. As our study suggests there could very well be a cocktail effect of CO2 and global warming, toxins like mercury, and other factors as well."Most of the prehistoric mass extinctions have indeed come in the wake of LIP volcanism, causing climate change and emitting toxic substances, Sofie Lindström says."Still, it is very difficult to say how big the importance of one factor is, because mass extinctions like this are very likely very complex events. Our study shows that mercury affected the ferns and likely also other plants, and it may also have had an impact on the entire food chain."The researchers point out that their study of the end-Triassic mass extinction in many ways draws parallels to the current global situation."Our global society emits a lot of the same substances and greenhouse gases as these huge volcanic provinces did during these mass extinctions. Therefore, studies in what happened back then might help us to prevent it from happening again," says Sofie Lindström.
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Extinction
| 2,019 |
October 25, 2019
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https://www.sciencedaily.com/releases/2019/10/191025110314.htm
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Did an extraterrestrial impact trigger the extinction of ice-age animals?
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A controversial theory that suggests an extraterrestrial body crashing to Earth almost 13,000 years ago caused the extinction of many large animals and a probable population decline in early humans is gaining traction from research sites around the world.
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The Younger Dryas Impact Hypothesis, controversial from the time it was presented in 2007, proposes that an asteroid or comet hit the Earth about 12,800 years ago causing a period of extreme cooling that contributed to extinctions of more than 35 species of megafauna including giant sloths, sabre-tooth cats, mastodons and mammoths. It also coincides with a serious decline in early human populations such as the Clovis culture and is believed to have caused massive wildfires that could have blocked sunlight, causing an "impact winter" near the end of the Pleistocene Epoch.In a new study published this week in "We continue to find evidence and expand geographically. There have been numerous papers that have come out in the past couple of years with similar data from other sites that almost universally support the notion that there was an extraterrestrial impact or comet airburst that caused the Younger Dryas climate event," Moore says.Moore also was lead author on a previous paper documenting sites in North America where platinum spikes have been found and a co-author on several other papers that document elevated levels of platinum in archaeological sites, including Pilauco, Chile -- the first discovery of evidence in the Southern Hemisphere."First, we thought it was a North American event, and then there was evidence in Europe and elsewhere that it was a Northern Hemisphere event. And now with the research in Chile and South Africa, it looks like it was probably a global event," he says.In addition, a team of researchers found unusually high concentrations of platinum and iridium in outwash sediments from a recently discovered crater in Greenland that could have been the impact point. Although the crater hasn't been precisely dated yet, Moore says the possibility is good that it could be the "smoking gun" that scientists have been looking for to confirm a cosmic event. Additionally, data from South America and elsewhere suggests the event may have actually included multiple impacts and airbursts over the entire globe.While the brief return to ice-age conditions during the Younger Dryas period has been well-documented, the reasons for it and the decline of human populations and animals have remained unclear. The impact hypothesis was proposed as a possible trigger for these abrupt climate changes that lasted about 1,400 years.The Younger Dryas event gets its name from a wildflower, Dryas octopetala, which can tolerate cold conditions and suddenly became common in parts of Europe 12,800 years ago. The Younger Dryas Impact Hypothesis became controversial, Moore says, because the all-encompassing theory that a cosmic impact triggered cascading events leading to extinctions was viewed as improbable by some scientists."It was bold in the sense that it was trying to answer a lot of really tough questions that people have been grappling with for a long time in a single blow," he says, adding that some researchers continue to be critical.The conventional view has been that the failure of glacial ice dams allowed a massive release of freshwater into the north Atlantic, affecting oceanic circulation and causing the Earth to plunge into a cold climate. The Younger Dryas hypothesis simply claims that the cosmic impact was the trigger for the meltwater pulse into the oceans.In research at White Pond in South Carolina, Moore and his colleagues used a core barrel to extract sediment samples from underneath the pond. The samples, dated to the beginning of the Younger Dryas with radiocarbon, contain a large platinum anomaly, consistent with findings from other sites, Moore says. A large soot anomaly also was found in cores from the site, indicating regional large-scale wildfires in the same time interval.In addition, fungal spores associated with the dung of large herbivores were found to decrease at the beginning of the Younger Dryas period, suggesting a decline in ice-age megafauna beginning at the time of the impact."We speculate that the impact contributed to the extinction, but it wasn't the only cause. Over hunting by humans almost certainly contributed, too, as did climate change," Moore says. "Some of these animals survived after the event, in some cases for centuries. But from the spore data at White Pond and elsewhere, it looks like some of them went extinct at the beginning of the Younger Dryas, probably as a result of the environmental disruption caused by impact-related wildfires and climate change."Additional evidence found at other sites in support of an extraterrestrial impact includes the discovery of meltglass, microscopic spherical particles and nanodiamonds, indicating enough heat and pressure was present to fuse materials on the Earth's surface. Another indicator is the presence of iridium, an element associated with cosmic objects, that scientists also found in the rock layers dated 65 million years ago from an impact that caused dinosaur extinction.While no one knows for certain why the Clovis people and iconic ice-age beasts disappeared, research by Moore and others is providing important clues as evidence builds in support of the Younger Dryas Impact Hypothesis."Those are big debates that have been going on for a long time," Moore says. "These kinds of things in science sometimes take a really long time to gain widespread acceptance. That was true for the dinosaur extinction when the idea was proposed that an impact had killed them. It was the same thing with plate tectonics. But now those ideas are completely established science."
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Extinction
| 2,019 |
October 22, 2019
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https://www.sciencedaily.com/releases/2019/10/191022142208.htm
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New species take longer to arise in the Amazon
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Amazonia is home to the greatest number of species on earth, many now threatened, but a new study published October 22 in the open-access journal
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Working in Peru and Brazil, Weir recorded songs from a population of birds in one region and played them back to male birds from a related population in another distant location. A major function of song is to advertise territories, so males typically respond aggressively to playback of their own species' song, believing it to be an intruder; sometimes they come right up to the speaker and try to look in.For many of the 51 pairs of populations Weir studied in Amazonia, males responded aggressively to songs from the distant population, implying they continue to view them as members of the same species. Using DNA sequence differences to estimate how long these pairs of populations have been separated, Weir and Price estimated it takes about 3 million years of separation for levels of aggression (e.g. how closely birds come to the playback) to decline to half of that seen in response to their own population.For comparison, Weir conducted an identical study on 58 pairs of populations in North America. The corresponding time to loss of aggression was much quicker -- about half a million years. Why might this be? One factor apparently maintaining responses for a long time in Amazonia is that, unlike in temperate North America, males of many Amazonian species defend their territories all year round, even against other species. It is these species in which males tend to respond especially aggressively to songs from distant, related populations.The project took several visits, and involved encounters with jaguars, poisonous snakes, chiggers, several thousand ticks, and botfly infestations, yet, according to Weir, was exceptionally rewarding fieldwork that provides a salutary lesson. While one may argue that extinction of a species in Amazonia is potentially recoverable on a similar timescale to that induced by glaciations in North America (a 'mere' one to two million years), the new study's findings imply that the special, warm and aseasonal environments of the tropics slow that rate. The build-up of species in the tropics has apparently occurred over very long timescales, where slow speciation rates have been matched by even slower extinction rates, making them especially important repositories of biodiversity.
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Extinction
| 2,019 |
October 22, 2019
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https://www.sciencedaily.com/releases/2019/10/191022080721.htm
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New study underpins the idea of a sudden impact killing off dinosaurs and much of the other life
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Fossil remains of tiny calcareous algae not only provide information about the end of the dinosaurs, but also show how the oceans recovered after the fatal asteroid impact. Experts agree that a collision with an asteroid caused a mass extinction on our planet, but there were hypotheses that ecosystems were already under pressure from increasing volcanism. "Our data speak against a gradual deterioration in environmental conditions 66 million years ago," says Michael Henehan of the GFZ German Research Centre for Geosciences. Together with colleagues from the University of Yale, he published a study in the scientific journal "
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He investigated isotopes of the element boron in the calcareous shells of plankton (foraminifera). According to the findings, there was a sudden impact that led to massive ocean acidification. It took millions of years for the oceans to recover from acidification. "Before the impact event, we could not detect any increasing acidification of the oceans," says Henehan.The impact of a celestial body left traces: the "Chicxulub crater" in the Gulf of Mexico and tiny amounts of iridium in sediments. Up to 75 percent of all animal species went extinct at the time. The impact marks the boundary of two geological eras -- the Cretaceous and the Palaeogene (formerly known as the Cretaceous-Tertiary boundary).Henehan and his team at Yale University reconstructed the environmental conditions in the oceans using fossils from deep-sea drill cores and from rocks formed at that time. According to this, after the impact, the oceans became so acidic that organisms that made their shells from calcium carbonate could not survive. Because of this, as life forms in the upper layers of the oceans became extinct, carbon uptake by photosynthesis in the oceans was reduced by half. This state lasted several tens of thousands of years before calcareous algae spread again. However, it took several million years until the fauna and flora had recovered and the carbon cycle had reached a new equilibrium.The researchers found decisive data for this during an excursion to the Netherlands, where a particularly thick layer of rock from the Cretaceous-Palaeogene boundary is preserved in a cave. "In this cave, an especially thick layer of clay from the immediate aftermath of the impact accumulated, which is really quite rare" says Henehan. In most settings, sediment accumulates so slowly that such a rapid event such as an asteroid impact is hard to resolve in the rock record. "Because so much sediment was laid down there at once, it meant we could extract enough fossils to analyse, and we were able to capture the transition," says Henehan.Most of the work was done at his former place of work, Yale University. Now, at the GFZ, he is using the infrastructure here and hopes that this will provide a major impetus for his work. "With the femtosecond laser in the HELGES laboratory, we are working to be able to measure these kind of signals from much smaller amounts of sample," says Henehan. "This will in the future enable us to obtain all sorts of information at really high resolution in time, even from locations with very low sedimentation rates."
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Extinction
| 2,019 |
October 21, 2019
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https://www.sciencedaily.com/releases/2019/10/191021161130.htm
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New deep-water coral discovered
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<em>Pax</em>
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Lately, submersibles have enabled marine scientists to explore these communities and collect samples, yielding a number of new octocoral species for the tropical eastern Pacific, including Adelogorgia hannibalis (2018), Thesea dalioi (2018) and Eugorgia siedenburgae (2013), all from the Hannibal Bank."Exploring the mesophotic zone and beyond has always been a challenge for scientists," said Hector M. Guzman, STRI marine ecologist. "We need submersibles or remotely operated underwater vehicles (ROVs) to search and collect specimens. Not always do we have access to these resources, but each time we go deep, we come up with something new.""Because, apart from our personal observations, we have found specimens in museum collections belonging to Psammogorgia that are the result of historical expeditions that acquired these samples by dredging down to mesophotic depths," said Odalisca Breedy, marine biologist at CIMAR and co-author of the study. "These specimens remain unidentified and have not been considered in any biodiversity assessments."The recent discovery and description of Meanwhile, the marine researchers remain concerned about the future of the Hannibal Bank seamount, whose rich biodiversity has only been recently explored. They consider that the area could benefit from stronger environmental and conservation protections."The management of this international protected seamount could be reinforced, as it faces heavy fishing pressure," Guzman said. "The same goes for the rest of Panamanian seamounts that we haven't explored yet for lack of resources."
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Extinction
| 2,019 |
October 21, 2019
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https://www.sciencedaily.com/releases/2019/10/191021161128.htm
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Humpback whale population on the rise after near miss with extinction
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A population of humpback whales in the South Atlantic has rebounded from the brink of extinction.
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Intense pressure from the whaling industry in the 20th century saw the western South Atlantic population of humpbacks diminish to only 450 whales. It is estimated that 25,000 whales were caught over approximately 12 years in the early 1900s.Protections were put in place in the 1960s as scientists noticed worldwide that populations were declining. In the mid-1980s, the International Whaling Commission issued a moratorium on all commercial whaling, offering further safeguards for the struggling population.A new study co-authored by Grant Adams, John Best and André Punt from the University of Washington's School of Aquatic and Fishery Sciences shows the western South Atlantic humpback (Megaptera novaeangliae) population has grown to 25,000. Researchers believe this new estimate is now close to pre-whaling numbers.The findings were published Oct. 16 in the journal "We were surprised to learn that the population was recovering more quickly than past studies had suggested," said Best, a UW doctoral student.The study follows a previous assessment conducted by the International Whaling Commission between 2006 and 2015. Those findings indicated the population had only recovered to about 30% of its pre-exploitation numbers. Since that assessment was completed, new data has come to light, providing more accurate information on catches -- including struck-and-lost rates -- and genetics and life-history."Accounting for pre-modern whaling and struck-and-lost rates where whales were shot or harpooned but escaped and later died, made us realize the population was more productive than we previously believed," said Adams, a UW doctoral student who helped construct the new model.By incorporating detailed records from the whaling industry at the outset of commercial exploitation, researchers have a good idea of the size of the original population. Current population estimates are made from a combination of air- and ship-based surveys, along with advanced modeling techniques.The model built for this study provides scientists with a more comprehensive look at the recovery and current status of the humpback population. The authors anticipate it can be used to determine population recovery in other species in more detail as well."We believe that transparency in science is important," said Adams. "The software we wrote for this project is available to the public and anyone can reproduce our findings."Lead author Alex Zerbini of the NOAA Alaska Fisheries Science Center's Marine Mammal Laboratory stressed the importance of incorporating complete and accurate information when conducting these assessments, and providing population assessments without biases. These findings come as good news, he said, providing an example of how an endangered species can come back from near extinction."Wildlife populations can recover from exploitation if proper management is applied," Zerbini said.The study also looks at how the revival of South Atlantic humpbacks may have ecosystem-wide impacts. Whales compete with other predators, like penguins and seals, for krill as their primary food source. Krill populations may further be impacted by warming waters due to climate change, compressing their range closer to the poles."Long-term monitoring of populations is needed to understand how environmental changes affect animal populations," said Zerbini.
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Extinction
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October 21, 2019
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https://www.sciencedaily.com/releases/2019/10/191021153343.htm
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GenBank can be trusted, study shows
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Did a murderer walk through the room? Did a shark just swim by? Is this a poisonous mushroom? Which reef species are lost when the coral dies? These questions can potentially be answered quickly and cheaply based on tiny samples of DNA found in the environment. But identifying DNA requires a trustworthy library of previously identified DNA sequences for comparison. Smithsonian scientists and their colleagues analyzed more than 4.7 million animal DNA sequences from GenBank, the most commonly used tool for this purpose, and discovered that animal identification errors are surprisingly rare -- and sometimes quite funny.
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"We wanted to use GenBank to identify DNA from ocean water samples as we evaluate the health of coral reefs and other marine ecosystems, but we were concerned by reports questioning the accuracy of the data there," said Matthieu Leray, post-doctoral fellow at the Smithsonian Tropical Research Institute (STRI). "In our sequence comparisons, we found fewer errors than people had predicted, which is a very good news, because monitoring programs and conservation efforts increasingly rely on analysis of environmental DNA."The reliability of data in GenBank, the virtual library maintained by the U.S. National Center for Biotechnology Information at the National Institutes of Health, where geneticists deposit DNA sequences from all living creatures, has been questioned in the past. An article entitled "Can You Bank on GenBank?" published in "We assumed that we would find lots of errors when we started the study," said Nancy Knowlton, scientist emeritus at STRI and at the Smithsonian's National Museum of Natural History."Some people think that GenBank is just a data dump," said Leray. "No one checks to see if the data are entered correctly. Researchers just upload their sequence data and they don't have to deposit a specimen anywhere in particular, so if there is a question, there may be no way to go back to the source to find out if a sequence is correct. We needed to be sure that GenBank was a good tool to use to identify marine organisms in our samples, so we decided to find out."With colleagues from Academia Sinica and the George Washington University, Leray and Knowlton estimated the proportion of sequences with incorrect genus, family, order, class and phylum names. Overall, less than 1 percent of the sequences were mislabeled. They identified certain groups of animals that are particularly problematic and some of the potential sources of error like mislabeling and contamination from humans, rodents, lab animals, food, mosquitos and pets like dogs and cats."For example, when you enter sequence data, at some point there is a drop-down menu giving choices of different species," Leray said. "Some people evidently just clicked on the wrong species, the one above or below the name of the species they were trying to enter. This part of the process could be fixed to lower the error rate even further."Direct DNA identification is a fast, low-cost way to answer many questions about the environment, and GenBank is a reliable tool to use to identify the source of the DNA. The authors concluded: "Our encouraging results suggest that the rapid uptake of DNA-based approaches is supported by a bioinformatic infrastructure capable of assessing both the losses to biodiversity caused by global change and the effectiveness of conservation efforts aimed at slowing or reversing these losses."
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Extinction
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October 21, 2019
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https://www.sciencedaily.com/releases/2019/10/191021103902.htm
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Biodiversity of insects modeled from space satellite data
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The quantity and diversity of plants and animals, especially insects, is decreasing, also in Germany. For this reason, science would like to see opportunities to document the biodiversity of the planet as extensively and comprehensively as possible. In this way, it could be determined whether measures against the insect dieback are effective or not.
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Satellite data are well suited for this purpose. "So far, however, they have hardly been used. Scientists were of the opinion that there were no freely available data that would provide sufficientresults," says Professor Jörg Mueller from the Biocenter of Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. This is not true. Radar data available free of charge can be used very well to monitor biodiversity from space.This was reported by Mueller's colleague Dr. So-yeon Bae with an international team in The JMU-led research team compared two methods. In five forest areas, whose biodiversity was very well known by by ground truths, twelve species groups were analysed -- on the one hand with high-resolution laser scanning data and on the other hand with coarser radar data.The results were astounding: "The free radar data provide comparably good results and are sometimes even superior to the laser," says Dr. Bae. Her conclusion: "Remote sensing is ready to carry out biodiversity monitoring from space throughout Germany. Now only better, standardized biodiversity data have to be collected on the ground nationwide." This would require spatially distributed mapping of species diversity in all forest habitats in Germany.
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Extinction
| 2,019 |
October 18, 2019
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https://www.sciencedaily.com/releases/2019/10/191018080617.htm
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Whole genome sequencing could help save pumas from inbreeding
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When students at the University of California, Santa Cruz (UCSC) found a dead mule deer on campus, they figured it had been killed by coyotes. Wildlife biologist Chris Wilmers rigged up a video camera to spy on the carcass at night. But the animal that crept out of the shadows to dine on the deer was no coyote -- it was a mountain lion.
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Mountain lions, or pumas, stay close to their prey, "so it must have been hiding in a nearby gorge all day," says Howard Hughes Medical Institute Investigator Beth Shapiro, an evolutionary biologist at UCSC.The persistent puma was already well-known by Wilmers, who had radio-collared and tagged him as part of a long-term study of California mountain lions. But now the animal, dubbed 36m, is becoming even more famous: he's the first puma to have his complete genome deciphered by scientists.The information in 36m's genes may lead to better conservation strategies, Shapiro, Wilmers, and their colleagues report October 18, 2019, in the journal Such work could stop inbreeding in its tracks and help keep local populations from going extinct, Shapiro says. "This is the first time that whole genomes have been used in this way."The team's new sequencing work is not the first effort to unlock pumas' genetic secrets. Years of painstaking research by geneticist Stephen O'Brien, molecular ecologist Warren Johnson, and others had previously shown that Florida's tiny population of pumas (also known as cougars or panthers) had become dangerously inbred, resulting in health defects like holes in their hearts and missing testicles. These abnormalities threatened the animals' ability to reproduce.The research team also proved that the introduction of eight female cougars from west Texas in 1995 had added enough new genes to boost health and help the population grow from about 30 individuals to more than 120. But the team's effort was limited by the genetic technology available at the time, which relied on analyzing just small snapshots of DNA, or markers, scattered throughout the genome. So the scientists didn't have a complete picture of the pumas' genes.Animals get two versions of every gene -- one from mom and, usually, a different one from dad. This means that offspring have the genetic diversity needed to keep populations healthy. But when populations become small and isolated, relatives breed with each other. As a result, genetic diversity plunges, and many genome locations end up with two identical versions of a gene. That's when weird things happen to animals, like the kinked tails, damaged hearts, and malformed sperm found in the inbred Florida panthers before the infusion of Texas cougar genes.Using DNA markers alone, scientists can estimate the average amount of genetic variation within a population and get a rough picture of the level of inbreeding. But this approach can't say whether major stretches of DNA between those markers contain copies of genes that are the same. These runs of identical gene copies are crucial, says Johnson, who is at the Walter Reed Biosystematics Unit and affiliated with the Smithsonian Conservation Biology Institute's Center for Species Survival.The number and length of these stretches provide a precise measure of both the extent of inbreeding and how recent it is -- and, therefore, how close a population is to falling off a genetic cliff. Inbreeding is not a slow and progressive process, Shapiro explains. Instead, once enough long runs of DNA with identical copies accumulate, the effects of inbreeding kick in suddenly, like turning off a light switch, she says.Shapiro is best known for recovering and sequencing tiny bits of DNA from ancient bones, charting the genetic changes in mammoths and other now-extinct animals as their numbers shrank. But she also has a keen interest in applying the same techniques to existing creatures, like the North American mountain lion. She wants to learn more about the genetic roads to extinction -- and possibly prevent those creatures from suffering the same fate. While talking with Wilmers one day about the Santa Cruz lion population, the two scientists realized that a crucial piece of information was missing: the puma's complete genetic sequence.Using blood that Wilmers had already collected from puma 36m, Shapiro and her team, including graduate student Nedda Saremi and postdoc Megan Supple, read the lion's entire genome to serve as a reference for the species. Then, for comparison, they sequenced the genomes of nine other mountain lions using stored samples -- another from the Santa Cruz area, two from the Santa Monica mountains, one from Yellowstone, three from Florida, and one from Brazil.The work let Shapiro see what had taken years to figure out in Florida -- that the translocation of Texas cougars had boosted genetic diversity and health of the Florida panthers. The sequences also brought new insights: even after mixing in the Texas DNA, the Florida population remains closer to the genetic brink than previously thought. "The big takeaway is that translocation worked, but the lights are going to go off because they continue to inbreed," Shapiro explains.Similarly, the population in the Santa Cruz Mountains "is not doing as well as we expected," she says. The 10 genomes also held controversial hints that mountain lions may have existed in North America far longer than previously thought -- as many as 300,000 years, instead of fewer than 20,000 years. "What Beth and her students are able to learn from just 10 individuals greatly extends what could be inferred with traditionally used DNA markers," Johnson says.More insights will come as scientists ramp up whole genome sequencing. Sequencing the full genomes of many individuals across a species' range is "tremendously valuable," explains Brad Shaffer, director of the UCLA La Kretz Center for California Conservation Science. "That can tell us a lot about the potential for climate adaptation and other critical conservation goals." And with costs rapidly declining -- Shapiro says reading 36m's genome cost about $10,000, down from $30,000 a couple of years ago, with subsequent lions sequenced for just $400 each -- O'Brien and others are pushing for a much larger effort. "Whole genome sequencing should be done for every critter we can catch," says O'Brien, of Nova Southeastern University.Already, Shapiro's work is shining a powerful new spotlight on the genetic health of individual mountain lions and populations, pointing the way to more effective conservation strategies. Isolated populations, for example, may benefit from wildlife bridges across major highways, to allow animals to wander more widely. In other cases, scientists may need to move animals from one region to another. Overall, a more complete picture of the genome makes it possible to spot populations at greatest risk for inbreeding ¬- and the best candidates for translocation."Now we can make more informed decisions," says Johnson. "In the past, we made decisions based on limited genetic information." The new approach takes out much of the uncertainty about a population's genetic heritage, he says. It also offers clues about how to preserve genetic variation and may help populations adapt to change.Though puma 36m didn't live to see any of these advances, his genetic legacy will remain. "While 36m was a badass puma by any measure, he might one day come to be the most recognized puma anywhere," Wilmers wrote in a tribute."[His] will be the puma genome against which other puma genomes can be compared and used to test all sorts of evolutionary and ecological questions."
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Extinction
| 2,019 |
October 17, 2019
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https://www.sciencedaily.com/releases/2019/10/191017141116.htm
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Mapping global biodiversity change
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A new study, published in
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The international team of scientists examined longitudinal variation in species richness and composition by piecing together and mapping over 50,000 biodiversity time series from studies across the planet using the biodiversity database BioTIME, hosted at the University of St Andrews, to establish clear geographic variation in biodiversity change.Scientists were then able to dissect variation in biodiversity trends to identify the places and types of organisms that are changing most rapidly. Detecting geographic variation in biodiversity trends will not only improve understanding of how global biodiversity is changing but also inform conservation priorities by identifying which regions to protect and which regions to help recover.Lead researcher Dr Maria Dornelas, from the School of Biology at the University of St Andrews, said: "Our study shows biodiversity is changing everywhere, but we are not losing biodiversity everywhere. Some places are recovering and adapting."When biodiversity is in the news these days, it is often because the Amazon is on fire, or there is a global mass mortality event in coral reefs, and rightly so, because these are terrifying news. However, there is a lot of recovery also taking place silently in the background, and many places where not much is happening. Our study puts these things on the map and shows they are not contradictory."We knew that biodiversity is affected by many different human actions, with different timings and effects, but we didn't have a clear understanding of what were the net effects of these actions across the planet.""Our study shows how biodiversity change varies geographically. The species that make up local assemblages are changing everywhere, but these changes are happening faster in marine compared to terrestrial assemblages," said Shane Blowes, the first author from the German Centre for Integrative Biodiversity Research (iDiv).Sarah Supp, from Denison University in Ohio and joint first author of the paper, added: "Biodiversity change is complex to understand because it can be measured in many different ways, including the number of unique species, and the identities of those species. Our study shows that while some locations have experienced decreases in the numbers of species, others show increases or little change at all. More consistently, however, the identities of species appear to be changing at nearly all sites -- this kind of change is critical to planning conservation and management strategies, particularly for sites exhibiting rapid turnover."Our study provides an important description of biodiversity change across the planet and highlights the value of monitoring biodiversity through time. Further, it provides motivation to increase our data sharing and establishing new long-term field sites to include greater geographic coverage -- for example, more tropical and freshwater systems."McGill researcher and coauthor Dr. Andrew Gonzalez concluded: "the Earth is going through a great geographic reorganization of its biodiversity in response to human activities and climate change. Given what we know it is likely this will continue for decades to come."
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Extinction
| 2,019 |
October 17, 2019
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https://www.sciencedaily.com/releases/2019/10/191017132229.htm
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Museums put ancient DNA to work for wildlife
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Scientists who are trying to save species at the brink of extinction are finding help in an unexpected place.
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Heather Farrington, curator of zoology for the Cincinnati Museum Center, is using DNA from specimens collected more than 100 years ago to help understand the evolution and stresses faced by today's animals.Farrington runs the museum's new state-of-the-art genetics laboratory, which helps researchers study populations of animals over time.Researchers increasingly are embracing the power of ancient DNA from old museum specimens to answer questions about climate change, habitat loss and other stresses on surviving populations. Ancient DNA has been used to explain the diversity of livestock in Africa and the first domestication of wild horses in Asia.Farrington earned her doctorate in biological sciences from the University of Cincinnati, where she charted the family trees of Galapagos finches and used the latest DNA tools to gain fresh insights about the birds from century-old museum specimens.The museum's genetics lab works with researchers and government agencies on a variety of projects that require DNA analysis, from conserving wildlife to improving our understanding of the natural world.Recently, the lab helped with a conservation project on the Allegheny woodrat, a small rock-loving rodent that is in decline across much of its historic range from Indiana to New Jersey. In Ohio it's found in only one place, the Richard and Lucille Durrell Edge of Appalachia Preserve, a mix of mature forest and limestone cliffs along the Ohio River.The museum's lab analysis found that Ohio's woodrats are maintaining their genetic diversity so far despite their geographic isolation.The lab also has studied the genetics of Ohio's crayfish and a beautiful yellow-and-black songbird called a hooded warbler.The museum's DNA lab has glass walls on two sides so the public can watch scientists at work. Next door, visitors also can watch museum staff and volunteers prepare fossils from a public gallery at the paleontology lab.Farrington's colleague, museum collections manager Emily Imhoff, explained how the sensitive equipment works.The lab keeps DNA samples in refrigerators, including one set to a chilly minus-112 degrees Fahrenheit. Scientists can identify the concentration of DNA, amplify the sample and sequence it to understand the lineage and relationships of species."We definitely feel our work is useful when we take on projects with other researchers," Imhoff said. "Heather and I are both passionate about our work."Farrington was looking for a graduate program in aquatic ecology that could satisfy her growing curiosity about genetics. UC biology professor Kenneth Petren, who served as dean of UC's McMicken College of Arts and Sciences, reached out to recruit her to UC."He said, 'Well, I do genetics, but I don't do fish. I work on Darwin's finches,'" Farrington said.At UC, Petren has conducted two decades of research on descendants of birds that shaped Charles Darwin's understanding of evolution through natural selection in the Galapagos Islands of Ecuador."I thought, 'Oh, my gosh, I can't say no to Darwin's finches,'" Farrington said.Farrington, Petren and UC biology professor Lucinda Lawson authored a study of finch populations that was published recently in the journal Farrington developed many of the important lab techniques she uses at the museum while conducting research at UC, Petren said."While at UC, Heather worked very hard to pioneer the use of museum specimens for population genetics analysis," Petren said. "Our lab was a leader in this field because of Heather's efforts."She used the techniques she developed to address issues of conservation in several different species of Galapagos finches," Petren said. "She went on to become a leader in the field of environmental DNA in her role working for the U.S. Department of Defense, which was interested in monitoring rare species or to provide early warnings of problematic invasive species like the Asian carp."Farrington said her experience while researching museum specimens for her dissertation at UC convinced her of how valuable these resources can be for future study. "That is really what got me into museum work and the amazing things you can learn from museum specimens," Farrington said.
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Extinction
| 2,019 |
October 16, 2019
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https://www.sciencedaily.com/releases/2019/10/191016124633.htm
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3-D printed coral could help endangered reefs
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Natural disasters such as hurricanes often leave devastation in their wake. Residents living in affected areas are sometimes displaced or require temporary shelter while their homes -- or even neighborhoods -- are repaired or rebuilt.
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But what if you are a fish and your home is a coral reef?Researchers across the globe are searching for ways to help endangered reefs, and the animals that live there, withstand or recover from weather events, including bleaching and storms that can occur with increasingly warmer water temperatures.One idea is to use 3D-printed coral models to replace or supplement coral reef systems that have been affected.New research by the University of Delaware's Danielle Dixson and UD alumnus Emily Ruhl has shown that 3D-printed objects do not impact the behavior of coral-associated damselfish or the survival of a settling stony coral.Further, the study demonstrated that fish showed no preference between materials used to 3D-print artificial corals, opening the door to using environmentally friendly materials, such as biodegradable cornstarch instead of plastic.With mounting concerns about plastic pollution in the marine environment, it is timely evidence that can support environmentally conscious decisions about what is put in the ocean.The researchers reported their results in Like others studying this problem, Dixson and Ruhl are looking for ways to keep the right animals on a reef after an emergency to fuel recovery. One important consideration is knowing that any 3D-printed material used won't harm coral or negatively affect fish behavior."If the fish on a reef won't use the 3D-printed coral models as a habitat in the wild, it could place them at greater risk for predation by other larger species," said Dixson, an associate professor in UD's College of Earth, Ocean and Environment's School of Marine Science and Policy. "If coral larvae won't settle on 3D-printed materials, they can't help to rebuild the reef."In laboratory experiments, the researchers studied the behavior of damselfish and mustard hill coral larvae in the presence of a coral skeleton and four 3D-printed coral models made from different filaments. Blue-green damselfish (Chromis viridis) are a common coral-associated fish found in the Indian and Pacific Oceans, while mustard hill corals (Porites astreoides) are a stony coral found in the Caribbean Sea.The 3D coral models were made by replicating a coral skeleton using 50 iPhone images of the coral taken from all angles and a 3D printer. The researchers 3D-printed four different artificial coral models from low-cost, widely available filaments, including polyester and two biodegradable materials, one made from cornstarch and another made from cornstarch combined with stainless steel powder.The researchers placed the damselfish into a fish tank loaded with the coral skeleton and the four artificial habitat options, in what is known as a cafeteria-style choice experiment, and studied whether the fish preferred one habitat over another.Behavior analysis showed the damselfish did not display a preference between the native coral skeleton and the 3D-printed coral materials. The fish's activity level, such as frequency of movement and distance the fish traveled in the tank, also remained unchanged regardless of what coral habitat they were provided.Ruhl said she was surprised that the fish behaved the same near artificial coral even with a natural coral skeleton present."I thought the natural skeleton would elicit more docile (that is, accepting) behavior compared to 3D-printed objects," said Ruhl, who earned her master's degree in marine biosciences at UD in 2018. "But then we realized the small reef fish didn't care if the habitat was artificial or calcium carbonate, they just wanted protection."The researchers' lab experiments also revealed that mustard hill coral larvae settled at much higher rates on 3D-printed surfaces compared to having no settlement surface at all, which could occur if a reef were flattened in a storm.This is promising news since both reef-associated fish and coral are vulnerable animal species, making them a good proxy for understanding how other reef organisms will respond to 3D-printed materials in the open ocean.As coral reefs degrade, they often lose structural complexity, which is a problem for reef-associated fish that rarely move more than 15 feet from home in their entire lives. Without proper habitat, coral reef associated juvenile fish don't grow up to be bigger fish, and without bigger fish that feed on competitive algae, the algae can overgrow live corals, causing destruction and placing the whole ecosystem at risk.In ongoing work, the researchers are analyzing field data from Fiji where they deployed 3D-printed coral and tiles made from biodegradable cornstarch filaments after determining they were safe to use. They are analyzing what settled on the artificial tiles, with an eye toward methods that would support conservation efforts."Offering 3D-printed habitats is a way to provide reef organisms a structural starter kit that can become part of the landscape as fish and coral build their homes around the artificial coral," Dixson said. "And since the materials we selected are biodegradable, the artificial coral would naturally degrade over time as the live coral overgrows it."In addition, 3D-printed coral models can be useful as a control for fish-related laboratory studies, enabling researchers to provide each fish an identical habitat, something that is currently not possible with the use of coral skeletons, Dixson said..Ruhl, who conducted the original research with Dixson as a UD graduate student, is now a research biologist with the U.S. Army Corps of Engineers' Engineer Research and Development Center in Mississippi. There, Ruhl studies freshwater fish behavior and cognition to find ways to mitigate invasive species, such as Asian carp. It's a role she snagged with the help of fellow CEOE alumna Kaytee Pokrzywinski, illustrating the power of the Blue Hen alumni network. In the future, Ruhl would like to become an officer with the National Oceanic and Atmospheric Administration (NOAA) Corps.
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Extinction
| 2,019 |
October 11, 2019
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https://www.sciencedaily.com/releases/2019/10/191011131905.htm
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The impact of human-caused noise pollution on birds
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Anthropogenic noise pollution (ANP) is a globally invasive phenomenon impacting natural systems, but most research has occurred at local scales with few species. Researchers in this study investigated continental-scale breeding season associations with ANP for 322 bird species to test whether local-scale predictions related to breeding habitat, migratory behavior, body mass, and vocal traits are consistent at broad spatial extents for an extensive group of North American bird species in the continental United States.
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For each species, researchers calculated the association between the breeding season occurrence and ANP, using spatially-explicit estimates of ANP from the National Park Service and weekly estimates of probabilities of occurrence based on observations from the eBird citizen?science database from 2004 to 2011.Species that breed in human modified habitats were associated with twice the level of ANP as species breeding in forested habitats. Residents and migratory species did not differ in their associations with ANP, but songs were less complex among forest breeding species and increased in complexity with increasing ANP. These findings suggest that local ANP observations do not necessarily scale-up to continental extents. However, the findings do indicate that vocal traits, such as song complexity, could be useful to understand how ANP is affecting birds across spatial scales.
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Extinction
| 2,019 |
October 9, 2019
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https://www.sciencedaily.com/releases/2019/10/191009162428.htm
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Infectious disease in marine life linked to decades of ocean warming
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New research shows that long-term changes in diseases in ocean species coincides with decades of widespread environmental change.
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The paper, "Increases and decreases in marine disease reports in an era of global change," was published Oct. 9 in Understanding oceanic trends is important for evaluating today's threats to marine systems, and disease is an important sentinel of change, according to senior author Drew Harvell, professor of marine biology at Cornell University."Disease increases and decreases can both be bad news," said lead author Allison Tracy, who studied with Harvell. "The long-term changes in disease that we see here may result from anthropogenic pressure on plants and animals in the ocean."The researchers examined marine infectious disease reports from 1970 to 2013, which transcend short-term fluctuations and regional variation. They examined records of corals, urchins, mammals, decapods, fish, mollusks, sharks, rays, seagrass and turtles.For corals and urchins, reports of infectious disease increased over the 44-year period. In the Caribbean, increasing coral disease reports correlated with warming events. It is widely known that coral bleaching increases with warming, but Harvell said they have established a long-term connection between warming and coral disease."We've finally linked a coral killer like infectious disease to repeated warming bouts over four decades of change," she said. "Our study shows that infectious disease reports are associated with warm temperature anomalies in corals on a multi-decadal scale."These results improve understanding of how changing environments alter species interactions, and they provide a solid baseline for health of marine life in the period studied.The research was funded by a National Science Foundation Ecology and Evolution of Marine Infectious Diseases grant.
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Extinction
| 2,019 |
October 9, 2019
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https://www.sciencedaily.com/releases/2019/10/191009075416.htm
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How bats relocate in response to tree loss
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Identifying how groups of animals select where to live is important for understanding social dynamics and for management and conservation. In a recent
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The colony began moving to a new patch of forest approximately seven kilometers away when cumulative loss of trees, over three years, in the old patch reached 18%. Most bats roosted in the new patch by year four, when cumulative loss of roost trees reached 46%.The authors noted that to maintain high densities of suitable roost trees for bats, management plans must retain live and dead trees in multiple stages of growth and decay."This is the first time that the movement of bats in response to a natural loss of roost trees has been documented. Our work suggests that general patterns for how bats respond to loss of roost trees may exist across bat species and forest types," said lead author Kristin Bondo, MSc, PhD, of the University of Regina, in Canada.
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Extinction
| 2,019 |
October 9, 2019
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https://www.sciencedaily.com/releases/2019/10/191009093905.htm
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New large-sized insect species discovered in tropical forest
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Scientists at the Biodiversity Unit of the University of Turku in Finland have studied the diversity of tropical parasitoid wasps for years. Parasitoid wasps are among the most species rich animal taxa on Earth, but their tropical diversity is still poorly known. Recently, the research group sampled Afrotropical rhyssine wasps, which are among the largest wasps. Scientists from three countries and research institutes participated in the research led by the University of Turku research group.
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Rhyssines are sizeable wasps that parasitise the beetle or wasp larvae of decaying wood. The largest species can grow over ten centimetres in length. Females carry an extremely long ovipositor, which is used to drill through wood, stab and paralyse the host, and lay eggs.Large-sized insect species are usually known better than small species, but tropical rhyssines are an exception."A good example of how poorly tropical rhyssines are known is the species Epirhyssa overlaeti, which is the largest African rhyssine. Only two females were known before, one collected in the 1930s in the Congo and the other one in Cameroon in the 1980s. Now, at one single Ugandan site, we found large numbers of both females and males. This completely changed what is known of the distribution of the species," says Doctoral Candidate Tapani Hopkins from the Biodiversity Unit of the University of Turku, who led the project.Scientists at the Biodiversity Unit of the University of Turku have previously studied the diversity of rhyssine wasps especially in the Amazonian lowland rainforest."In our Amazonian research, we have described ten large-sized South-American species new to science and our understanding of the diversity of South American tropical rainforest parasitoid wasps has changed. Extending the research to the African continent is important, because our goal is to understand the global diversity of the parasitoid insects which are extremely species rich," says Professor in Biodiversity Research Ilari Sääksjärvi from the Biodiversity Unit of the University of Turku.In the newest study, two new African tropical parasitoid wasp species were described."We named one of the new species Epirhyssa quagga, because its colouration resembles that of a zebra. The other species became Epirhyssa johanna. The name Johanna refers to my wife," Hopkins says delightedly.
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Extinction
| 2,019 |
October 3, 2019
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https://www.sciencedaily.com/releases/2019/10/191003141553.htm
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Ant-plant partnerships may play unexpected role in ant evolution
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Partnerships between ant and plant species appear to arise from -- but not drive -- rapid diversification of ants into new species. Katrina Kaur of the University of Toronto, Canada, and colleagues present these findings in
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Some plants and ants have mutually beneficial, or "mutualistic," interactions: plants provide ants with food or shelter, while ants protect plants against herbivores or disperse their seeds. Previous research has shown that plants with ant partners diversify faster -- showing a bigger net difference between extinction rates and the rise of new plant species -- than do other plants.Kaur and colleagues wondered if plants affect ant evolution similarly. However, the data they needed was buried in thousands of scientific papers each discussing just one or a few ant species. So, they wrote a computer program to "read" and extract data from over 89,000 paper abstracts, successfully assembling a large database of ant ecological interactions. Then, they mapped the data onto an ant evolutionary tree and modeled how partnering with plants has affected ant diversification.The analysis produced unexpected results. The researchers hypothesized that ants would first evolve mutualism with plants and then diversify, but their model suggests the opposite: ants that are already rapidly diversifying are more likely to evolve a plant partnership. Once they do, their diversification rates slow."To our surprise, the intimate and often beneficial relationships that ants have with plants apparently did not help to generate the over 14,000 ant species on Earth today," Kaur says. "Mutualism may put the brakes on the rise of new species or increase the threat of extinction because an ant's fate becomes linked to its plant partner's."The researchers plan to use their "text-mining" computer program to assemble an even larger database from thousands of additional papers in order to understand why ant-plant partnerships have different effects on ant versus plant evolution. A similar approach could also reveal insights about other species in mutualistic relationships, such as seed-dispersing birds or human gut microbes.
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Extinction
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October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002165228.htm
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Besides hot water, coral bleaching also about location, location, location
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As conservationists grapple with unprecedented levels of coral reef bleaching in the world's warming oceans, scientists in the Indian and Pacific Oceans used the most recent El Niño of 2016 (the warmest year on record) to evaluate the role of excess heat as the leading driver of coral bleaching.
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The findings were, in a word, complicated, according to marine researchers from WCS (Wildlife Conservation Society) and other groups. Specifically, the WCS-led study revealed a more complex view than current standard predictions of coral bleaching events caused primarily by heat stress; rather, the scientists found that bleaching is driven by a variety of stressors, and each region responds differently.The authors note that any good predictions of the future will need to consider these complexities, specifically because they are important for effective policies, management, and conservation plans.The new study titled "Temperature patterns and mechanisms influencing coral bleaching during the 2016 El Niño" appears in the latest edition of "Our results suggest that coral responses to global climate change may be changing as corals have different past experiences and tolerances to heat and stress," said Dr. Tim McClanahan, WCS Senior Conservation Zoologist and co-author of the study. "The consequence is that management and policies need to be aligned with the locations and types of stresses if we are to identify potential refugia and other priority actions for coral reefs."The widespread coral bleaching in the Indo-Pacific during the most recent El Niño event (2014-2017) was the latest in a series of thermal stresses to impact corals in the region, preceded by events in 1983, 1988, 1998, 2005, 2010, and 2013. The year 2016 brought about the most severe bleaching episodes, including extensive mortality in the Great Barrier Reef.Coral communities are symbiotic relationships between animals (corals) and algae that give their hosts color and sustenance. According to previous studies and field observations, coral bleaching generally occurs when corals expel their algae while under stress from water temperatures significantly above normal. Reefs closer to the warmer equator have also bleached more in the past and expected to degrade further in 2016.But assessments made from the field during the study -- with data collected from 226 sites stretching from East Africa to Fiji -- found that coral bleaching patterns did not neatly align with past predictors of excess temperature and distance from the equator. Instead, bleached corals were highly variable in terms of warm water temperatures and location, with some reefs suffering bleaching levels of up to 60 percent and others surviving with no impact.To determine what other mechanisms are at work in coral bleaching events, the scientists evaluated 26 variables and more than 2000 models that were solved by a supercomputer to test the effects of factors such as thermal exposure, depth, habitat, coral community composition, and the types of management used in reef systems.In terms of geography, the researchers found that bleaching depended greatly on where the corals lived along the longitudinal gradient from East Africa to Fiji, with the strongest bleaching observed in East Africa. Consequently, some regions, it seems, will be affected earliest and worse than other regions.Examining seawater temperatures 90 days before the bleaching, the researchers found that the best predictors of coral bleaching were highest average temperatures, how long cool water endured prior to peak temperatures, and the existence of two peaks in temperature. However, this depended on where the reefs were located, and East African reefs were found to be more stressed than reefs in Indonesia and Fiji. Thus, it was general stress rather than just warm water that affected corals the most, and some coral locations responded to stress better than others did.
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Extinction
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October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002144241.htm
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New imaging platform examines mechanisms behind coral bleaching
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As coral reefs deteriorate in the face of climate change, an interdisciplinary Northwestern Engineering research team has developed an innovative method to image coral nanoscale structures and quantify pigment absorption in live corals, an indicator of coral health. The imaging platform could become a valuable tool to help marine biologists better understand coral physiology as well measure and monitor coral health.
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Reef building corals provide a home to more than 1 million species in our oceans. Yet increasing ocean temperatures have given rise to coral bleaching, a phenomenon where corals expel their life-providing algae, jeopardizing the health and sustainability of colonies."Coral reefs provide critically important ecosystems, but they are bleaching at alarming rates due to global warming," said Luisa Marcelino, research assistant professor of civil and environmental engineering at Northwestern Engineering. "In order to develop strategies to prevent coral reef death, it is critical to understand the mechanisms of bleaching. However, there are no current means to image live coral tissue due to the complexity of its structure."The team from the McCormick School of Engineering published its insights in a paper titled "Measuring Light Scattering and Absorption with Inverse Spectroscopic Optical Coherence Tomography (ISOCT): A New Tool for Non-invasive Monitoring" on October 2 in the journal The research expands upon Marcelino and Backman's previous work studying coral, which includes developing a quantitative coral bleaching response index in 2016. The first database of its kind, the index used historical data to measure the statistical mass density distribution of coral skeletons, a trait tied to bleaching susceptibility. The index also detailed which of the world's coral species are most at risk of bleaching and most likely to perish as a result of thermal stress caused by warming oceans.When the coral index was created, the team couldn't image coral samples non-invasively. The new imaging technique, called inverse spectroscopic optical coherence tomography (ISOCT), uses lasers to scan living coral and measure its optical properties at full 3D resolution."We originally developed ISOCT to image human tissues in order to better understand alterations in early carcinogenesis," said Backman, who leads Northwestern's Center for Physical Genomics and Engineering. "We had to adapt and enhance it for coral imaging, which produced an exciting example of cross-pollination in science and technology."Not only does ISOCT provide greater clarity into the statistical mass density distribution of the skeleton and tissues of different coral species, it also quantifies the chemical concentration within coral, including levels of chlorophyll and other fluorescent pigments."Corals have adapted through evolution to harvest light in a specific way. As the environment changes and oceans get warmer, the ability to adapt to those changes might be affected by their basic physiology," said Graham Spicer (PhD '19), a co-first author on the study and former PhD student in Backman's lab. "ISOCT provides spatially-resolved information, so we can study exactly how species of coral might adapt better than others to environmental changes."By illuminating new insights into how coral adapts to environmental stresses, the team believes ISOCT could help marine biologists create new strategies to protect particularly susceptible species from bleaching due to climate change."The new imaging technique provides the first comprehensive analysis of the structure and function of live corals, which is a critical step toward better understanding how corals bleach and die," Backman said. "Understanding these processes may help design strategies to slow down or prevent coral bleaching."Spicer added that a greater understanding of corals could also present new opportunities on another environmental front -- solar capture."Corals have adapted over millions of years to harvest light in an optimal way given their environment," Spicer said. "If we could fully understand the mechanisms by which corals have been optimized via evolution to harvest light, we could develop similar strategies as the basis for solutions to harvest solar energy."
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Extinction
| 2,019 |
October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002144239.htm
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Warming impedes a coral defense, but hungry fish enhance it
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Corals create potions that fight bacterial attackers, but warming appears to tip the scales against the potions as they battle a bacterium common in coral bleaching, according to a new study. Reef conservation may offer hope: A particular potion, gathered from reefs protected against seaweed overgrowth, proved more robust.
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The protected Pacific reefs were populated by diverse corals and shimmered with colorful fish, said researchers who snorkeled off of Fiji to collect samples for the study. Oceanic ecologists from the Georgia Institute of Technology compared coral potions from these reefs, where fishing was prohibited, with those from heavily fished reefs, where seaweed inundated corals because few fish were left to eat it.The medicated solutions, or potions, may contain a multitude of chemicals, and the researchers did not analyze their makeup. This is a possible next step, but here the researchers simply wanted to establish if the potions offered any real defense against pathogens and how warming and overfishing might weaken it."I thought I probably wouldn't see antibiotic effects from these washes. I was surprised to see such strong effects, and I was surprised to see that reef protections made a difference," said the study's first author, Deanna Beatty."There is a lot of argument now about whether local management can help in the face of global stresses -- whether what a Fijian village does matters when people in London and Los Angeles burn fossil fuels to drive to work," said Mark Hay, the study's principal investigator, Regents Professor and Harry and Linda Teasley Chair in Georgia Tech's School of Biological Sciences."Our work indicates that local management provides a degree of insurance against global stresses, but there are likely higher temperatures that render the insurance ineffective."The researchers collected three coral species along with seawater surrounding each species at protected reefs and at overfished reefs. In their Georgia Tech lab, they tested their solutions against the pathogen "We chose "We chose 24 C and 28 C because they're representative of the variations you see on Fijian reefs these days. Those are temperatures where the bacteria are more benign or more virulent," Beatty said.The data showed that warming disadvantaged all potions against The unprotected reefs' shabby appearance portended their effects on the one potion associated with a key coral species."When you swim out of the no-fishing area and into the overfished area, you hit a hedge of seaweed. You have about 4 to 16% corals and 50 to 90% seaweed there. On the protected reef, you have less than 3% seaweed and about 60% corals," Hay said.Hay has researched marine ecology for over four decades and has seen this before, when coral reefs died off closer to home."Thirty years ago, when Caribbean reefs were vanishing, I saw overfishing as a big deal there, when seaweed took over," he said, adding that global warming has become an overriding factor. "In the Pacific, many reefs that were not overfished have been wiped out in warming events. It just got too hot for too long."The potions are products of the corals and associated microbes, which comprise a biological team called a holobiont.To arrive at potions focused on chemical effects, the researchers agitated the coral holobionts and ocean water then freeze-dried and irradiated the resulting liquid to destroy remnants of life that could have augmented chemical action. Some viruses may have withstood sterilization, but it would have weakened any effect they may have had, if there were any.Then the researchers tested the potions on "All of the solutions' defenses were compromised to varying extents at elevated temperatures where we see corals getting sick in the ocean," Hay said.But reef protection benefited the potion taken from the species "The beneficial effect in the solution tested in the lab was better when Of the three species with potions that were tested, It is part of a genus -- larger taxonomic category -- containing about 150 of the roughly 600 species in Pacific reefs, and "If fish can hang on, they may buy
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Extinction
| 2,019 |
October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002110329.htm
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African evidence support Younger Dryas Impact Hypothesis
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A team of scientists from South Africa has discovered evidence partially supporting a hypothesis that Earth was struck by a meteorite or asteroid 12 800 years ago, leading to global consequences including climate change, and contributing to the extinction of many species of large animals at the time of an episode called the Younger Dryas.
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The team, led by Professor Francis Thackeray of the Evolutionary Studies Institute at the University of the Witwatersrand in Johannesburg, South Africa, discovered evidence of a remarkable "platinum spike" at a site called Wonderkrater in the Limpopo Province, north of Pretoria in South Africa. Working with researcher Philip Pieterse from the University of Johannesburg and Professor Louis Scott of the University of the Free State, Thackeray discovered this evidence from a core drilled in a peat deposit, notably in a sample about 12 800 years old. This research was published in Noting that meteorites are rich in platinum, Thackeray said "Our finding at least partially supports the highly controversial Younger Dryas Impact Hypothesis (YDIH). We seriously need to explore the view that an asteroid impact somewhere on earth may have caused climate change on a global scale, and contributed to some extent to the process of extinctions of large animals at the end of the Pleistocene, after the last ice age."Many mammals became extinct in North America, South America and Europe at the time of the Younger Dryas. In South Africa a few extraordinary large animal species became extinct, not necessarily at exactly 12 800 years ago, but close to that period. These megafauna include a giant African buffalo, a large zebra, and a very big wildebeest.Human populations may also have been indirectly affected at the time in question. In North America there is a dramatic termination of the stone tool technology of Clovis people. Remarkably, archaeologists in South Africa have detected an almost simultaneous termination of the Robberg stone artefact industry associated with people in some parts of the country, including the area around Boomplaas near the Cango Caves in the southern Cape, close to the town of Oudshoorn."Without necessarily arguing for a single causal factor on a global scale, we cautiously hint at the possibility that these technological changes, in North America and on the African subcontinent at about the same time, might have been associated indirectly with an asteroid impact with major global consequences," says Thackeray. "We cannot be certain, but a cosmic impact could have affected humans as a result of local changes in environment and the availability of food resources, associated with sudden climate change."At Wonderkrater, the team has evidence from pollen to show that about 12 800 years ago there was temporary cooling, associated with the "Younger Dryas" drop in temperature that is well documented in the northern hemisphere, and now also in South Africa. According to some scientists, this cooling in widespread areas could at least potentially have been associated with the global dispersal of platinum-rich atmospheric dust.A large crater 31 kilometres in diameter has been discovered in northern Greenland beneath the Hiawatha Glacier. "There is some evidence to support the view that it might possibly have been the very place where a large meteorite struck the planet earth 12 800 years ago," says Thackeray. "If this was indeed the case, there must have been global consequences."Thackeray's team believes their discovery of a platinum spike at about 12 800 years ago at Wonderkrater is just part of the strengthening view that an asteroid or cometary impact might have occurred at that time.This is the first evidence in Africa for a platinum spike preceding climate change. Younger Dryas spikes in platinum have also been found in Greenland, Eurasia, North America, Mexico and recently also at Pilauco in Chile. Wonderkrater is the 30th site in the world for such evidence."Our evidence is entirely consistent with the Younger Dryas Impact Hypothesis" says Thackeray.The discovery in South Africa is expected to be integrated with those made in other parts of the world, recognising that the source of the platinum at Wonderkrater could hypothetically be cosmic dust that was dispersed in the atmosphere after a meteorite impact in Greenland.The probability of a large asteroid striking Earth in the future may seem to be low, but there are thousands of large rocks distributed primarily between Jupiter and Mars. One in particular, classified as Apophis 99942, is referred to as a "Potentially Hazardous Asteroid." It is 340 meters wide and will come exceptionally close to the Earth in 10 years' time."The closest encounter will take place precisely on Friday April 13, 2029," says Thackeray. "The probability of the Apophis 99942 asteroid hitting us then is only one in 100,000, but the probability of an impact may be even higher at some time in the future, as it comes close to Earth every 10 years."The South African research has been supported by the National Research Foundation and the DST/NRF Centre of Excellence for the Palaeosciences.
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Extinction
| 2,019 |
October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002110325.htm
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Fossil fish gives new insights into evolution after end-Cretaceous mass extinction
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An international research team led by Giuseppe Marramà from the Institute of Paleontology of the University of Vienna discovered a new and well-preserved fossil stingray with an exceptional anatomy, which greatly differs from living species. The find provides new insights into the evolution of these animals and sheds light on the recovery of marine ecosystems after the mass extinction occurred 66 million years ago. The study was recently published in the journal
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Stingrays (Fossil remains of stingrays are very common, especially their isolated teeth. Complete skeletons, however, exist only from a few extinct species coming from particular fossiliferous sites. Among these, Monte Bolca, in northeastern Italy, is one of the best known. So far, more than 230 species of fishes have been discovered that document a tropical marine coastal environment associated with coral reefs which dates back to about 50 million years ago in the period called Eocene.This new fossil stingray has a flattened body and a pectoral disc ovoid in shape. What is striking is the absence of sting and the extremely short tail, which is not long as in the other stingrays, and does not protrude posteriorly to the disc. This body plan is not known in any other fossil or living stingray. Since this animal is unique and peculiar, the researchers named the new stingray More than 70 percent of the organisms, such as dinosaurs, marine reptiles, several mammal groups, numerous birds, fish and invertebrates, disappeared during the fifth largest extinction event in the Earth's history occurred about 66 million years ago at the end of the Cretaceous. In marine environments, the time after this event is characterized by the emergence and diversification of new species and entire groups of bony and cartilaginous fishes (sharks and rays), which reoccupied the ecological niches left vacant by the extinction's victims. The new species experimented sometimes new body plans and new ecological strategies."From this perspective, the emergence of a new body plan in a 50-million-year-old stingray such as
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Extinction
| 2,019 |
October 2, 2019
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https://www.sciencedaily.com/releases/2019/10/191002075927.htm
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Researchers use drones to weigh whales
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By measuring the body length, width and height of free-living southern right whales photographed by drones, researchers were able to develop a model that accurately calculated the body volume and mass of the whales.
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Because of their large size and aquatic life, previously the only way to obtain data on the body mass of whales was to weigh dead or stranded individuals.The innovative method can be used to learn more about the physiology and ecology of whales, "Knowing the body mass of free-living whales opens up new avenues of research. We will now be able to look at the growth of known aged individuals to calculate their body mass increase over time and the energy requirements for growth. We will also be able to look at the daily energy requirements of whales and calculate how much prey they need to consume." said Assistant Professor Fredrik Christiansen from Aarhus Institute of Advanced Studies in Denmark and lead author of the study.Dr. Michael Moore, a Senior Scientist at the Woods Hole Oceanographic Institution and co-author said: "Weight measurements of live whales at sea inform how chronic stressors affect their survival and fecundity, as well as enabling accurate sedative dosing of animals entangled in fishing gear that are aversive to disentanglement attempts."The model is already being used to assess the impacts of kelp gull harassment on the health and survival of southern right whale calves. Dr. Mariano Sironi and Dr. Marcela Uhart from the Southern Right Whale Health Monitoring Program and co-authors, emphasized "The use of drones to estimate whale weight and condition, as well as to individually track calves while they grow beside their mothers, has been a real breakthrough in our investigation.""In the past we've had to rely entirely upon stranded carcasses which added all sorts of uncertainties to our studies."The model also allowed the researchers to collaborate with the Digital Life Project at the University of Massachusetts, USA to first recreate a 3D mesh of the whale, and then to work with CG artist Robert Gutierrez to recreate the full-colour 3D model of the right whale. These models can be used for both scientific purposes, such as studying movement, as well as for educational uses.By adjusting the parameters of the model, the approach could be used to estimate the size of other marine mammals where alternative, more invasive, methods aren't feasible or desirable.Baleen whales, which include species like the blue whale, are the largest animals on this planet, with body mass being central to their success as an animal group. However, data on their size has historically been limited to dead specimens, with most samples coming from whaling operations, accidental fisheries bycatch or beach strandings.Collecting data on dead whales has limitations such as being unable to collect longitudinal data over a whale's life span and inaccuracies from physical distortion of carcasses caused by bloating and deflation.Assistant Professor Christiansen explained that "The difficulty in measuring body mass reliably in free-living whales, has prevented the inclusion of body mass in many studies in ecology, physiology and bioenergetics. This novel approach will now make it possible to finally include this central variable into future studies of free-living whales."To calculate the body volume and mass of southern right whales the researchers first took aerial photos of 86 individuals off the coast of Península Valdés, Argentina. The clear waters and the large number of whales that gather there every winter for breeding made it an ideal place to collect high quality images of both the dorsal and lateral sides of the whales. From these they were able to obtain length, width and height measurements.These measurements could then be used to accurately model the body shape and volume of the whales. "We used this model to estimate the body volume of whales caught in scientific whaling operations, for which body girth and mass was known. From these estimates of body volume, we could then calculate the density of the whales, which we in turn could use to estimate the mass of free-living whales photographed by our drones." Said Christiansen.Although the model yielded body mass estimates to a high-level of accuracy, there were some limitations due to the relative proportion of different tissues in baleen whales. Christiansen said, "We had to assume a constant body density of the whales, which is not realistic as the proportion of different body tissues (fat, muscle etc.) changes seasonally as the whales deposit or lose body condition."
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Extinction
| 2,019 |
October 1, 2019
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https://www.sciencedaily.com/releases/2019/10/191001125113.htm
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Predators and hidey-holes are good for reef fish populations
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New research highlights two factors that play a critical role in supporting reef fish populations and -- ultimately -- creating conditions that are more favorable for the growth of both coral reefs and seagrass.
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"Previous work has shown mixed results on whether the presence of large predator species benefits reef fish populations, but we found that the presence of Nassau grouper (Epinephelus striatus) had an overall positive effect on fish abundance," says Enie Hensel, a former Ph.D. student at North Carolina State University and lead author of a paper on the work. "We also found that habitat complexity benefits both fish abundance and species richness, likely because it gives fish a larger variety of places to shelter." This is consistent with previous work."One of the surprises here was that the effect of predator presence on fish abundance was comparable to the effect of habitat complexity," Hensel says.To better understand the effect of these variables, researchers constructed 16 artificial "patch" reefs in shallow waters off the coast of Great Abaco Island in The Bahamas. Eight of the reefs consisted of cement-filled cinder blocks, mimicking degraded reefs with limited habitat complexity. The remaining eight reefs consisted of unfilled cinder blocks and branching pipe structures, mimicking the more complex physical environment of healthier reefs.Once in place, the researchers waited for groupers to move in and claim the new reef territory. The groupers were large juveniles, ranging in size from 16-33 centimeters. The researchers then removed the groupers from four of the degraded reef sites and from four of the complex reef sites. Groupers that were removed were relocated to distant reefs.Researchers monitored the sites for 60 days to ensure that the grouper-free reefs remained free of groupers. At the end of the 60 days, the researchers assessed the total number of fish at each reef site, as well as the total number of fish species at each site.The differences were significant.Fish abundance, or the total number of fish, was highest at sites that had both a resident grouper and complex habitat. Abundance at these sites ranged from 275 fish to more than 500 -- which is remarkable given that each reef was less than a meter long in any direction. By comparison, sites that had simple structures and no grouper had fewer than 50 fish on average. Simple structures with predators had around 75 fish, while complex sites without grouper had around 100."We think the presence of the grouper drives away other predators, which benefits overall fish abundance," Hensel says. "And a complex habitat offers niches of various sizes and shapes, which can shelter more and different kinds of fish than a degraded, simple habitat."The presence of grouper had little or no effect on species richness, or the number of different species present at each site. However, habitat complexity made a significant difference. Complex sites had 11-13 species, while degraded sites had around seven."We found that the sites with complex habitats and the presence of predators had fish populations that were actually larger than what we see at surrounding, similar-sized natural reefs," Hensel says. "That's because the natural reefs in the area are all degraded due to a variety of stressors."We also found that the presence of grouper on complex reefs led to a significant jump in the population of Tomtate grunts (Haemulon aurolineatum)," Hensel says. "That's good news, because Tomtates are a species that provides a lot of ecosystem services, which would be good for creating conditions that are more amenable to both coral reef growth and seagrass growth."Currently, my colleagues and I are building from these findings in two directions. We're measuring long-term community and ecosystem level responses to coral restoration or the reintroduction of structurally complex habitat; and we are also measuring long-term biological and physiological responses of fishes residing on restored reefs. For the latter, Haley Gambill, an undergraduate at NC State, is measuring changes in the age and growth of grunts."It's also worth noting that this is an area that was hit hard by Hurricane Dorian. Because we've done so much reef population work in that area, I'm hoping to return to do some work that can help us understand how extreme weather events can affect these ecosystems."The work was done with support from the National Science Foundation under grants 0746164 and 1405198.
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Extinction
| 2,019 |
September 30, 2019
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https://www.sciencedaily.com/releases/2019/09/190930161859.htm
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What did ancient crocodiles eat? Study says as much as a snout can grab
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While most people imagine alligators and crocodiles as being much the same now as they were during the age of dinosaurs, digging into the fossil record shows much more diverse species through time. Semiaquatic ambush predators resembling modern alligators and crocodiles are seen in fossil relatives going back to the Jurassic period, but the group also includes oceangoing crocs with flippers and tail flukes, heavily armored pug-faced crocs, long-legged crocs that ran on land, and giant crocs with tiny teeth and surfboard-shaped skulls.
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Many of these odd adaptations seem to be associated with what the animals were eating, but how do scientists study the diet of animals that have been dead for millions of years?Two researchers -- one from the University of Tennessee, Knoxville, and one from Stony Brook University -- have tried to tackle this question by bringing together mathematical analyses of the animals' shapes, surveys of modern crocodiles' diet, modeling methods for reconstructing the diet of fossil groups, and forensic-style interpretations of damaged bones from the distant past."We used to put modern crocs into two ecological bins: slender-snouted groups who eat only fish and broader-snouted groups who eat pretty much whatever they want," said paleontologist Stephanie Drumheller, an adjunct assistant professor in UT's Department of Earth and Planetary Sciences and coauthor of the paper, published in Slender-snouted crocodiles, such as Indian gharials and freshwater crocodiles, actually eat all sorts of animals other than fish, though they do tend to stick with smaller prey relative to their body size. Among the crocs that eat larger prey, the researchers found an unexpected split. Broad V-shaped snouts, like those found in American crocodiles, correspond with animals that are able to eat prey species up to their own size. More U-shaped snouts, like those seen in American alligators, can often be found in species that take down even larger prey -- sometimes close to twice their own body weight."Several of these fossil groups had skulls and teeth wildly different from living species. This suggests that the way they fed also differed dramatically," said coauthor Eric Wilberg, an assistant professor in Stony Brook University's Department of Anatomical Sciences. Among these are a group of extinct crocs that lived in the oceans. While they had slender snouts similar to those of living gharials, their eyes were positioned more on the side of the head, and the part of the skull that houses the jaw muscles was enlarged. This suggests they were not ambush predators like modern crocodylians.Another group consists almost exclusively of species that lived on land. These crocs had flattened, serrated teeth, like those of carnivorous dinosaurs, and eyes positioned more on the side of the head.Paleontologists can't observe feeding in extinct groups, but the fossil records sometimes provide snapshots of this behavior."Crocodiles and their relatives are pretty messy eaters," said Drumheller. "That's great for us, because they'll often leave broken, bitten bones behind for paleontologists to find."Most of these fossil bite marks line up nicely with the idea of crocodiles and their relatives eating within their expected weight classes. The fossils that don't fit may be evidence of scavenging, a behavior that is rarely testable in the fossil record.Some crocodile groups remain mysterious. No fossil bite marks exist for the stubby-faced crocs, whose complex teeth and weak jaws suggest they might have been plant eaters, or for the surfboard-headed ones, which had tiny teeth and may have sported pelican-like pouches under their long, wide jaws."Crocodiles and their relatives have long been thought of as unchanged for hundreds of millions of years, and as a result they have received less scientific attention than other groups like dinosaurs and mammals," said Wilberg. Renewed interest in the group has consistently demonstrated a complex evolutionary and ecological history, going far beyond the semiaquatic ambush predators alive today.
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Extinction
| 2,019 |
September 30, 2019
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https://www.sciencedaily.com/releases/2019/09/190930161854.htm
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Collapse of desert bird populations likely due to heat stress from climate change
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As temperatures rise, desert birds need more water to cool off at the same time as deserts are becoming drier, setting some species up for a severe crash, if not extinction, according to a new study from the University of California, Berkeley.
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The team that last year documented a collapse of bird communities in Mojave Desert over the last century -- 29 percent of the 135 bird species that were present 100 years ago are less common and less widespread today -- has now identified a likely cause: heat stress associated with climate change.The researchers' latest findings, part of UC Berkeley's Grinnell Resurvey Project, come from comparing levels of species declines to computer simulations of how "virtual birds" must deal with heat on an average hot day in Death Valley, which can be in the 30s Celsius -- 90s Fahrenheit -- with low humidity. These temperatures are, on average, 2 C (3.6 F) hotter than 100 years ago. The birds that the model predicted would require the most extra water today, compared to a 100 years ago, were the species that had declined the most in the Mojave Desert over the past century. The desert straddles the border between California and Nevada.The most threatened turn out to be larger birds, and those that have an insect or animal diet."We often think that climate change may cause a mass mortality event in the future, but this study tells us that the change in climate that has already occurred is too hot, and in certain areas, animals can't tolerate the warming and drying that has already occurred," said lead author Eric Riddell, a UC Berkeley postdoctoral scholar.The virtual bird simulation was unique in allowing the researchers to identify the impact of a daily physiological stressor in the desert -- heat -- as birds leave the shade to forage for food or find mates. Other aspects of a changing environment, such as changing food sources and fire, only add to the heat stress."This is one of the first studies that directly ties the increase in physiological demands from a warmer and drier climate to the changes that are taking place in biodiversity," said senior author Steven Beissinger, a UC Berkeley professor of environmental science, policy and management and a researcher at the Museum of Vertebrate Zoology at Berkeley. "Most previous studies have not found a direct physiological connection between climate change and biodiversity change, which is usually mediated through changes in the food web or competing species. Our study points to a direct effect of climate change via increased water demands for evaporative cooling to maintain body temperature in the comfort zone."According to Beissinger, the team's conclusions about these California and Nevada desert birds may apply to species in other regions of the world."Warmer, drier conditions are expected to spread with climate change, so we are probably looking at an increase, for birds in this kind of evaporative water demand, in a lot of places," he said. "Some of these effects might not just be limited to the desert. Does it matter to an insectivore that doesn't drink water if it is in the hot desert or in your hot hometown, say Atlanta? As the climate warms, I am not so sure."Beissinger, Riddell and their colleagues detailed their findings in a paper to be published this week in the journal The Grinnell Resurvey Project, a 15-year effort to revisit and record wildlife at sites around California visited by UC Berkeley biologist Joseph Grinnell and his colleagues at the Museum of Vertebrate Zoology between 1904 and 1940. The comparison of the state's mammal and bird life over more than a century has revealed the changes wrought by climate change to date and provided insight into what may happen in coming decades as global warming continues.Like humans, birds regulate their internal temperatures to keep within a comfortable range. But they do not sweat. Like dogs, they pant, but can also vibrate their throat muscles in what's called a gular flutter. The resulting increase in air flow and evaporating water cools them off.The hotter they get, however, the more water they must exhale to lower their body temperature. The team calculated that larger birds, like the mourning dove, require 10% to 30% more water today to keep cool because of the 2 C increase in Mojave Desert temperatures over the last 100 years.According to the UC Berkeley analysis, birds that eat insects or other animals are more threatened by changes in evaporative water loss because they typically get all of their water from the moisture in their food. They seldom, if ever, drink from surface water sources. A 30% increase in water requirement could mean that larger birds have to catch an extra 60 to 70 bugs per day to survive the increased heat. If those bugs are even around, the birds still have to expend extra energy and time to find them.The team's field survey, led by postdoctoral researcher Kelly Iknayan and published last year, confirms this prediction: The American kestrel, prairie falcon and turkey vulture, all large and carnivorous, have declined, as have large insect-eaters like the white-throated swift, violet-green swallow, olive-sided flycatcher, Western meadowlark and Western bluebird.Smaller birds that eat seeds or are omnivores are less threatened, according to the model. In fact, the earlier study showed that small insectivores in the Mojave Desert -- the blue-gray gnatcatcher, ruby-crowned kinglet, mountain chickadee, black-tailed gnatcatcher, black-throated sparrow, verdin and canyon wren -- have suffered less over the past century.Vegetarian birds, such as seedeaters, face a different problem. Because they can drink from surface water sources -- springs and pools in desert oases, they can supplement the water they get from their food. But that's only if water is around. Even protected areas of the Mojave Desert -- Death Valley, Joshua Tree National Park and the Mojave National Preserve, where the bird surveys were conducted -- are getting drier from climate change and because of groundwater pumping by nearby cities and agricultural areas. As a result, the seedeaters are also at risk of heat-related death.The team's survey of birds in these parks confirmed that most seedeaters in areas with open sources of water have been impacted less by climate change over the last century."For plant-based eaters, it is more binary: whether or not a species survived at a site over the past 100 years had more to do with the presence or absence of surface water. If you could drink, you were better off than if you couldn't drink," Riddell said "For insect eaters, it is more dependent on the magnitude of cooling, determined by body size and feather absorbance. The greater its water requirements, the more a species declined. So, there are different ways in which climate change is manifesting itself for different members of the bird community."The researchers noted that some birds are adapting to the hotter temperatures by moving northward or up mountain slopes to find cooler habitats, while others are shifting their active nesting periods earlier in the year to avoid hotter summer temperatures. Some species are even becoming smaller, reducing their water needs. But birds can reduce their size only so much."We explored that possibility: how small would birds have to get to maintain the same levels of stress," Riddell said. "It was something ridiculous, like 35 to 50 percent smaller. That's not gonna happen, it is way too small."Riddell, who has a background in physics, modeled the heat balance of 50 different species of desert birds on a computer, obtaining physical data on each from specimens in the Museum of Vertebrate Zoology. These data included size, as well as reflectance of feathers, length of feathers and depth of feathers on the back and belly. He validated the model by comparing its predictions to data on heat balance in captive birds and also to experiments on physical bird models by researchers, including co-author Blair Wolf of the University of New Mexico in Albuquerque.He then ran the model, varying conditions for each bird species -- from staying in the sun all day to remaining in the shade all day -- at various temperatures. Death Valley holds the record high temperature on Earth: 134 F in 1913.From these virtual experiments, Riddell and his colleagues were able to obtain good estimates of the amount of extra water needed for evaporative cooling by each bird species today compared to 100 years ago, and what these birds will need in the future, under different climate change scenarios.Not surprisingly, larger birds turned out to require a higher amount of water today, and they represent many of the species most impacted since the early 20th century. Riddell predicts that, in the worst case scenario of climate change, larger birds like the mourning dove may require nearly twice their typical intake of water by the end of the century to remain cool enough to survive higher temperatures in the desert."People have been focusing on lethal thresholds for birds, but our metric was death by a thousand cuts: recurrent cooling costs that birds are going to have to deal with every day," Riddell said. "According to Kelly's work, we have seen a 50 percent reduction in species diversity at sites in the desert visited a century ago by Grinnell. This isn't really a question of when will it happen in the future, but understanding what we have already done, what has already happened."Barry Sinervo of UC Santa Cruz was also a co-author of the paper. The work was funded by the National Science Foundation (1457742).
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September 27, 2019
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https://www.sciencedaily.com/releases/2019/09/190927074930.htm
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Longest coral reef survey to date reveals major changes in Australia's Great Barrier Reef
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Coral reefs around the world are under increasing stress due to a combination of local and global factors. As such, long-term investigation is becoming increasingly important to understanding ecosystem responses.
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A new study -- the longest coral reef survey to date -- provides an in-depth look at Australia's Great Barrier Reef over the past 91 years. Published today in the journal "This is a unique opportunity to look at long-term changes on an inshore reef system," said author Prof. Hoegh-Guldberg from the University of Queensland. "Most studies are only a few decades in length -- this one is just short of 100 years of study."In 1928 the Great Barrier Reef Committee and the Royal Society of London sent an expedition to study the Great Barrier Reef. Members of the expedition, pioneers in coral biology and reef studies, lived on Low Isles for over a year. During this time they documented environmental conditions surrounding the coral reefs of the Low Isles, as well as the community structure of tidal and subtidal communities, using, for the first time, a diving helmet."What was critical to our study was how carefully the expedition in 1928 undertook their study," said lead author Prof. Maoz Fine, of the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University and the Interuniversity Institute for Marine Sciences. "We were literally able to go the exact spot and identify features that the 1928 expedition saw."Members of the expedition produced aerial photography-based mapping of the island. This highly-accurate mapping enabled researchers in the current study to follow in their footsteps and revisit and sample the exact intertidal and subtidal locations previously explored 76, 87 and 91 years later, thereby forming the longest ecological survey to date.In the latest investigation, carried out in three phases in 2004, 2015 and 2019, researchers discovered that intertidal communities have experienced major phase-shifts over nearly a century. Species richness and diversity of these communities systematically declined for corals and other invertebrates. Specifically, massive corals have replaced branching corals, and soft corals have become much more numerous."The degree to which reefs may shift from one state to another following environment change was overwhelming," said Prof. Fine. "The long-term implications of these changes highlight the importance of avoiding phase shifts in coral reefs which may take many decades to repair, if at all." According to Fine the multi-year study also illustrates the importance of considering multiple factors in the decline, and potential recovery, of coral reefs, and the importance of tracking changes in community structure, as well as coral abundance, over long periods.Coral reefs are highly sensitive to environmental change. Multiple stressors, in isolation or in combination, may lead to dramatic deterioration that can result in loss of reefs and their ecological services for many years. In the future the researchers hope to use the same methods to reconstruct data from other parts of the world where historical expeditions accurately documented similar communities.
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September 26, 2019
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https://www.sciencedaily.com/releases/2019/09/190926141713.htm
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Living coral cover will slow future reef dissolution
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A team led by David Kline, a staff scientist at the Smithsonian Tropical Research Institute, asked what would happen if they lowered the pH on a living coral reef. By using computer-controlled pulses of carbon dioxide (CO
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The ocean absorbs about half of the carbon produced by burning fossil fuels, making seawater more acidic. And according to a UN report, ocean acidity may double by 2100. But most of what is known about the effects of ocean acidification on corals comes from aquarium experiments."We wanted to get away from experiments in glass boxes and do them on the reef under natural conditions," Kline said. "But we never imagined the differences would be so dramatic.""During the eight-month experimental period we went through about five tanks of COpH and temperature normally fluctuate over a 24-hour period. So the team created a system to in-crease COLike sea shells, corals skeletons are made of calcium carbonate. And as seawater becomes more acidic, coral skeletons accumulate calcium carbonate more slowly or even dissolve, like chalk in a glass of vinegar."Using a FOCE system is not the only way to get at the effects of ocean acidification, it's part of a tool kit, but it gives us realistic predictions," Kline said. "The plus is that it generates consistent infor-mation from a real reef -- in natural light, food, nutrients and environmental conditions where the corals are exposed to the natural ecosystem of reef dwellers. The minus is that it is expensive and challenging to set up and run."The results of this first FOCE experiment on a shallow coral reef were grim: both living and dead corals were seriously affected by ocean acidification. The growth rates of living corals declined to almost zero while the rate of dissolution of dead colonies almost doubled. These results suggest that at the COCoral skeletons covered with living tissue were much more resilient than dead corals in this real-world experiment because they were protected from boring worms and other animals that feed on corals from within the coral skeletons, and also from sea urchins, parrotfish and other bioeroders living on the outer surface of the corals that ate the dead corals at a rapid rate."The huge difference between the fate of living and dead corals in a natural environment gives me hope," Kline said. "As we create marine reserves and learn how to increase the amount of living coral by restoring reefs, we're setting up a positive feedback loop because living coral will grow the reef and slow dissolution."Kline worked with colleagues from Scripps Institution of Oceanography, The University of Queensland, Stanford University, OceanX, Florida State University, Carnegie Institution and The He-brew University of Jerusalem."It was amazing to work together on Heron Island," he said. "It's a very well studied site: people have been doing research there for 100 years. Many of the landmark studies of coral reefs were done there." Now Kline's time machine is on its way to the other side of the world, where he will see if the same conclusions hold up at the Smithsonian's Caribbean Bocas del Toro Research Station in Panama.The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical biodiversity and its im-portance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.
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Extinction
| 2,019 |
September 24, 2019
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https://www.sciencedaily.com/releases/2019/09/190924143158.htm
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What wolves' broken teeth reveal about their lives
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UCLA evolutionary biologist Blaire Van Valkenburgh has spent more than three decades studying the skulls of many species of large carnivores -- including wolves, lions and tigers -- that lived from 50,000 years ago to the present. She reports today in the journal
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Essential to the survival of these carnivores is their teeth, which are used for securing their prey and chewing it, yet large numbers of these animals have broken teeth. Why is that, and what can we learn from it?In the research, Van Valkenburgh reports a strong link between an increase in broken teeth and a decline in the amount of available food, as large carnivores work harder to catch dwindling numbers of prey, and eat more of it, down to the bones."Broken teeth cannot heal, so most of the time, carnivores are not going to chew on bones and risk breaking their teeth unless they have to," said Van Valkenburgh, a UCLA distinguished professor of ecology and evolutionary biology, who holds the Donald R. Dickey Chair in Vertebrate Biology.For the new research, Van Valkenburgh studied the skulls of gray wolves -- 160 skulls of adult wolves housed in the Yellowstone Heritage and Research Center in Montana; 64 adult wolf skulls from Isle Royale National Park in Lake Superior that are housed at Michigan Technological University; and 94 skulls from Scandinavia, collected between 1998 and 2010, housed in the Swedish Royal Museum of Natural History in Stockholm. She compared these with the skulls of 223 wolves that died between 1874 and 1952, from Alaska, Texas, New Mexico, Idaho and Canada.Yellowstone had no wolves, Van Valkenburgh said, between the 1920s and 1995, when 31 gray wolves were brought to the national park from British Columbia. About 100 wolves have lived in Yellowstone for more than a decade, she said.In Yellowstone, more than 90% of the wolves' prey are elk. The ratio of elk to wolves has declined sharply, from more than 600-to-1 when wolves were brought back to the national park to about 100-to-1 more recently.In the first 10 years after the reintroduction, the wolves did not break their teeth much and did not eat the elk completely, Van Valkenburgh reports. In the following 10 years, as the number of elk declined, the wolves ate more of the elk's body, and the number of broken teeth doubled, including the larger teeth wolves use when hunting and chewing.The pattern was similar in the island park of Isle Royale. There, the wolves' prey are primarily adult moose, but moose numbers are low and their large size makes them difficult to capture and kill. Isle Royale wolves had high frequencies of broken and heavily worn teeth, reflecting the fact that they consumed about 90% of the bodies of the moose they killed.Scandinavian wolves presented a different story. The ratio of moose to wolves is nearly 500-to-1 in Scandinavia and only 55-to-1 in Isle Royale, and, consistent with Van Valkenburgh's hypothesis, Scandinavian wolves consumed less of the moose they killed (about 70%) than Isle Royale wolves. Van Valkenburgh did not find many broken teeth among the Scandinavian wolves. "The wolves could find moose easily, not eat the bones, and move on," she said.Van Valkenburgh believes her findings apply beyond gray wolves, which are well-studied, to other large carnivores, such as lions, tigers and bears.Extremely high rates of broken teeth have been recorded for large carnivores -- such as lions, dire wolves and saber-toothed cats -- from the Pleistocene epoch, dating back tens of thousands of years, compared with their modern counterparts, Van Valkenburgh said. Rates of broken teeth from animals at the La Brea Tar Pits were two to four times higher than in modern animals, she and colleagues reported in the journal Science in the 1990s."Our new study suggests that the cause of this tooth fracture may have been more intense competition for food in the past than in present large carnivore communities," Van Valkenburgh said.She and colleagues reported in 2015 that violent attacks by packs of some of the world's largest carnivores -- including lions much larger than those of today and saber-toothed cats -- went a long way toward shaping ecosystems during the Pleistocene.In a 2016 article in the journal BioScience, Van Valkenburgh and more than 40 other wildlife experts wrote that preventing the extinction of lions, tigers, wolves, bears, elephants and the world's other largest mammals will require bold political action and financial commitments from nations worldwide.Discussing the new study, she said, "We want to understand the factors that increase mortality in large carnivores that, in many cases, are near extinction. Getting good information on that is difficult. Studying tooth fracture is one way to do so, and can reveal changing levels of food stress in big carnivores."The research was funded by the National Science Foundation and National Park Service.
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Extinction
| 2,019 |
September 24, 2019
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https://www.sciencedaily.com/releases/2019/09/190924101442.htm
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Scientists decode DNA of coral and all its microscopic supporters
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Scientists have seen for the first time how corals collaborate with other microscopic life to build and grow.
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A study led by The University of Queensland and James Cook University reveals at the DNA level how coral interacts with partners like algae and bacteria to share resources and build healthy, resilient coral.UQ's Dr Steven Robbins said the research may aid in the revival of the world's embattled coral reefs."Symbiotic relationships are incredibly important for thriving corals," Dr Robbins said."The mostly striking example of this is coral bleaching, where corals expel their algal symbiotic partners at higher-than-normal water temperatures," he said."As algae make up the bulk of the coral's food through photosynthesis, the coral will die if temperatures don't cool enough to allow symbiosis to re-establish."It's possible that equally important interactions are happening between corals and their bacteria and single-cell microorganisms (archaea), but we just don't know."To properly manage our reefs, we need to understand how these relationships work, and genomics is one of our best tools."Genomics allows us to look at each organism's entire library of genes, helping us work out how coral symbiotic relationships might support coral health."In the research, the scientists took a sample of the coral In the lab, they separated the coral animal, its algal partner and all associated microbes, sequencing each organism's DNA."Once we've sequenced the genomes, we use computer algorithms to look at the entire library of genes that each organism has to work with," Dr Robbins said."This allows us to answer questions like, 'what nutrients does the coral need, but not make itself?'"Associate Professor David Bourne, from JCU and the Australian Institute of Marine Science (AIMS) said that having high-quality genomes for a coral and its microbial partners is hugely important."Large advances in human medicine have been achieved in the past 20 years since the human genome was decoded," he said."Over the next 20 years, similar knowledge of corals and how they function will emerge -- this data set represents a foundation for that."For the first time, we now have the genomes of a large number of the microbes that make up this coral, which is incredibly important for their survival."It's truly ground-breaking -- this is the blueprint for coral and their symbiotic communities."The researchers hope the research may help imperiled coral reefs globally."Our coral reefs support incredible diversity and when we lose reefs, we lose far more than corals," Dr Robbins said."There are many threats to coral, but climate change is the most existential for our reefs."In 2016 and 2017, nearly 50 per cent of all corals on the Great Barrier Reef died, and we don't see this trajectory reversing if carbon emissions remain at current levels."But, as scientists we can try to understand what makes corals tick to devise ways to make them more resilient, and we're delighted to have added to that body of knowledge."The researchers paid credit to Dr Sylvain Forêt from ANU, who contributed to the study up until his sudden death in 2016.
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Extinction
| 2,019 |
September 19, 2019
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https://www.sciencedaily.com/releases/2019/09/190919142331.htm
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US and Canada have lost more than 1 in 4 birds in the past 50 years
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A study published today in the journal
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"Multiple, independent lines of evidence show a massive reduction in the abundance of birds," said Ken Rosenberg, the study's lead author and a senior scientist at the Cornell Lab of Ornithology and American Bird Conservancy. "We expected to see continuing declines of threatened species. But for the first time, the results also showed pervasive losses among common birds across all habitats, including backyard birds."The study notes that birds are indicators of environmental health, signaling that natural systems across the U.S. and Canada are now being so severely impacted by human activities that they no longer support the same robust wildlife populations.The findings showed that of nearly 3 billion birds lost, 90 percent belong to 12 bird families, including sparrows, warblers, finches, and swallows -- common, widespread species that play influential roles in food webs and ecosystem functioning, from seed dispersal to pest control.Among the steep declines noted:"These data are consistent with what we're seeing elsewhere with other taxa showing massive declines, including insects and amphibians," said coauthor Peter Marra, senior scientist emeritus and former head of the Smithsonian Migratory Bird Center and now director of the Georgetown Environment Initiative at Georgetown University. "It's imperative to address immediate and ongoing threats, both because the domino effects can lead to the decay of ecosystems that humans depend on for our own health and livelihoods -- and because people all over the world cherish birds in their own right. Can you imagine a world without birdsong?"Evidence for the declines emerged from detection of migratory birds in the air from 143 NEXRAD weather radar stations across the continent in a period spanning over 10 years, as well as from nearly 50 years of data collected through multiple monitoring efforts on the ground."Citizen-science participants contributed critical scientific data to show the international scale of losses of birds," said coauthor John Sauer of the U.S. Geological Survey (USGS). "Our results also provide insights into actions we can take to reverse the declines." The analysis included citizen-science data from the North American Breeding Bird Survey coordinated by the USGS and the Canadian Wildlife Service -- the main sources of long-term, large-scale population data for North American birds -- the Audubon Christmas Bird Count, and Manomet's International Shorebird Survey.Although the study did not analyze the causes of declines, it noted that the steep drop in North American birds parallels the losses of birds elsewhere in the world, suggesting multiple interacting causes that reduce breeding success and increase mortality. It noted that the largest factor driving these declines is likely the widespread loss and degradation of habitat, especially due to agricultural intensification and urbanization.Other studies have documented mortality from predation by free-roaming domestic cats; collisions with glass, buildings, and other structures; and pervasive use of pesticides associated with widespread declines in insects, an essential food source for birds. Climate change is expected to compound these challenges by altering habitats and threatening plant communities that birds need to survive. More research is needed to pinpoint primary causes for declines in individual species."The story is not over," said coauthor Michael Parr, president of American Bird Conservancy. "There are so many ways to help save birds. Some require policy decisions such as strengthening the Migratory Bird Treaty Act. We can also work to ban harmful pesticides and properly fund effective bird conservation programs. Each of us can make a difference with everyday actions that together can save the lives of millions of birds -- actions like making windows safer for birds, keeping cats indoors, and protecting habitat."The study also documents a few promising rebounds resulting from galvanized human efforts. Waterfowl (ducks, geese, and swans) have made a remarkable recovery over the past 50 years, made possible by investments in conservation by hunters and billions of dollars of government funding for wetland protection and restoration. Raptors such as the Bald Eagle have also made spectacular comebacks since the 1970s, after the harmful pesticide DDT was banned and recovery efforts through endangered species legislation in the U.S. and Canada provided critical protection."It's a wake-up call that we've lost more than a quarter of our birds in the U.S. and Canada," said coauthor Adam Smith from Environment and Climate Change Canada. "But the crisis reaches far beyond our individual borders. Many of the birds that breed in Canadian backyards migrate through or spend the winter in the U.S. and places farther south -- from Mexico and the Caribbean to Central and South America. What our birds need now is an historic, hemispheric effort that unites people and organizations with one common goal: bringing our birds back."American Bird Conservancy (ABC) is a nonprofit organization dedicated to conserving birds and their habitats throughout the Americas. With an emphasis on achieving results and working in partnership, we take on the greatest problems facing birds today, innovating and building on rapid advancements in science to halt extinctions, protect habitats, eliminate threats, and build capacity for bird conservation.Bird Conservancy of the Rockies (Bird Conservancy) is a Colorado-based nonprofit that works to conserve birds and their habitats through an integrated approach of science, education, and land stewardship. Our work extends from the Rockies to the Great Plains, Mexico, and beyond. Together, we are improving native bird populations, the land, and the lives of people. Bird Conservancy's vision is a future where birds are forever abundant, contributing to healthy landscapes and inspiring human curiosity and love of nature.The Cornell Lab of Ornithology is a nonprofit member-supported organization dedicated to interpreting and conserving the earth's biological diversity through research, education, and citizen science focused on birds.Environment and Climate Change Canada is Canada's lead federal department for a wide range of environmental issues. It informs Canadians about protecting and conserving our natural heritage, and ensuring a clean, safe, and sustainable environment for present and future generations.Advancing Georgetown's commitment to the environment, sustainability, and equitability, the Georgetown Environment Initiative brings together students, faculty, and staff from across disciplines -- from the natural sciences, social sciences, humanities, public policy, law, medicine, and business -- to contribute to global efforts to deepen understanding of our world and to transform the Earth's stewardship.The Smithsonian Migratory Bird Center (SMBC) is dedicated to understanding, conserving, and championing the grand phenomenon of bird migration. Founded in 1991, and part of the Smithsonian Conservation Biology Institute, SMBC scientists work to conserve migratory species through research and public education that foster a better understanding of migratory birds and the need to protect diverse habitats across the Western Hemisphere.
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Extinction
| 2,019 |
September 17, 2019
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https://www.sciencedaily.com/releases/2019/09/190917115432.htm
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How much of corals' nutrition comes from hunting?
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When it comes to feeding, corals have a few tricks up their sleeve. Most of their nutrients come from microscopic algae living inside of them, but if those algae aren't creating enough sustenance, corals can use their tentacles to grab and eat tiny prey swimming nearby.
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A new study from researchers at the Woods Hole Oceanographic Institution (WHOI), the University of New Mexico, and Scripps Institution of Oceanography is revealing that more of corals' nutrients come from this sort of hunting than previously expected, information that may help predict the fate of coral reefs as global ocean temperatures rise. The study published Sept. 17, 2019, in the journal "When you have a heat wave, corals start bleaching. Symbiotic algae, which live inside corals and provide them with most of their nutrients, are expelled from their body. If corals stay bleached for too long they basically starve to death," says Michael Fox, a postdoctoral scholar at WHOI and lead author on the paper. "But if a coral has the opportunity to eat a lot before it bleaches or while it is bleached, it can survive off its fat stores long enough to regain those symbionts when water temperatures cool off. If we can better understand when, where, or why corals are eating, we may be able to understand why they survive better in some places than others during future bleaching events."Fox and his colleagues conducted their study from samples they collected at Palmyra Atoll, a remote US national wildlife refuge in the central Pacific Ocean. After bringing them back into the lab, the researchers removed the coral polyps from their skeletons, and then separated the coral animals and their symbiotic algae in a centrifuge. The team then extracted essential amino acids from the corals, their symbionts, and the tiny zooplankton that corals often eat."Essential amino acids are required for an animal to survive, but most corals can't make them. They have to get them from either their symbionts or something they just ate," says Fox. "But each of those sources make amino acids in different ways, which gives the molecules distinct chemical signatures."Those signatures can be used to "fingerprint" the source of the amino acid, he adds. By measuring chemical differences in six individual amino acids, the researchers were able to determine how much of a coral's nutrition was coming from symbionts, or from captured prey. This new method for measuring coral nutrition allows scientists to estimate the contributions of different food sources to coral diets, providing a more accurate view of their nutrition than previous methods. The technique was co-developed by animal ecologist Seth Newsome of the University of New Mexico, who is also a co-author on the study."To my knowledge, this has never been done with corals before. It really changed our perspective," says Fox. "Our findings suggest that some corals are eating a lot more than we previously thought, which has big implications for reef survival during climate change. We've also learned that individual corals of the same species can have very different diets -- this may be an important source of variation that we'll have to take into account to understand how corals will respond to future changes."
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Extinction
| 2,019 |
September 17, 2019
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https://www.sciencedaily.com/releases/2019/09/190917075835.htm
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Scientists identify previously unknown 'hybrid zone' between hummingbird species
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We usually think of a species as being reproductively isolated -- that is, not mating with other species in the wild. Occasionally, however, closely related species do interbreed. New research just published in
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A hybrid zone is an area where the ranges of two closely related species overlap and interbreed with one another. To map the extent of the hummingbird hybrid zone in northern California and southern Oregon, San Diego State University's Brian Myers and his colleagues collected data on the physical traits and courtship behavior of more than 300 hummingbirds in the region. Most of the breeding males across the hybrid zone had a mix of characteristics of the two species, shifting gradually from more Rufous-like birds in the north to more Allen's-like birds in the south.The males of different hummingbird species have distinct displays, performing aerial acrobatics during which their tail feathers produce various sounds. The researchers captured hummingbirds using traps at feeders, temporarily keeping females in mesh cages, where they caught the attention of territorial males. "Sometimes the birds outsmart me," says Myers. "They'll only visit a feeder when the trap isn't on it, or they won't perform their courtship displays to the female hummingbird I'm carrying around, and this can make things very slow sometimes."The area where Allen's and Rufous hummingbirds interbreed stretches more than 300 kilometers along the Pacific coast and 90 kilometers inland, and it could have implications for the species' futures. "When a hybrid zone is so large, and when one of the hybridizing species has as small a range as Allen's Hummingbird, it raises the possibility of their range shrinking even further as they're swamped by hybrids that carry Rufous Hummingbird traits and pass these genes into Allen's Hummingbird populations," says Myers. "As biodiversity continues to drop, it's more important than ever to understand how new species form and what maintains species barriers once they're made -- is there a certain habitat or other resources that require protection? Is it more related to sexual selection? Hybrid zones are an ideal tool with which to study this."
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Extinction
| 2,019 |
September 16, 2019
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https://www.sciencedaily.com/releases/2019/09/190916081500.htm
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Hope for coral recovery may depend on good parenting
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The fate of the world's coral reefs could depend on how well the sea creatures equip their offspring to cope with global warming.
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About half the world's coral has been lost due to warming seas that make their world hostile. Instead of vivid and floral, coral bleach pale as temperatures rise. This happens because the peculiar animal cohabitates with algae, which expel under stress. When that happens, coral lose their color and a life partner that sustains them, so they starve.Yet, hope occurs in aquariums at the USC campus near downtown Los Angeles and at the Australian Institute of Marine Science. There, biologists study coral's unusual ability to shuffle their so-called symbionts -- the algae colonies inside their cells -- as a coping mechanism to potentially gain an advantage in a changing environment. For the first time, the researchers have shown that adult coral can pass along this ability to shuffle their symbionts to their offspring. It's a process that occurs in addition to traditional DNA transfer, and it's never been seen before until scientists began captive breeding research in labs on both sides of the Pacific Ocean."What we're finding is that corals can pass their shuffled complement of algal partners, or symbionts, to their offspring to bestow a potential survival advantage, and that's a new discovery," said Carly Kenkel, an assistant professor of biology at the USC Dornsife College of Letters, Arts and Sciences. "We care about this because coral reefs do so much for us. A reef provides breakwater for storms, fish protein people need and biodiversity we love and find beautiful."The findings appear in a research paper published today in Scientists have known for a long time that coral and algae live in mutual harmony. The two creatures live as one: a soft-bodied polyp animal similar to a sea anemone or jellyfish and an algae living within its cells. The animal provides algae safety and substances for photosynthesis; the algae produce oxygen, help remove wastes and supply the coral with energy. Corals use the energy to make calcium carbonate, the rigid architecture that builds reefs, while the algae contribute to the creatures' jewel-tone hues that make coral spectacular.They live amicably together until environmental stress disrupts the partnership. When this happens, some coral succumb whereas others are capable of shuffling their symbionts, favoring some algae over others depending on water conditions, competition or available nutrients. "It's a messy divorce," Kenkel said.Yet in this breakup, the kids could benefit. Kenkel wanted to understand if parent coral could pass along the reshuffled symbionts to its offspring. It's a tricky proposition because the algae exist independent of the cell nucleus and therefore are not part of the nuclear DNA transfer, parent to offspring, during reproduction.Her curiosity took her to the Great Barrier Reef and Orpheus Island, off northeast Australia, where she joined scientists from James Cook University and the Australian Institute of Marine Science. The research team focused on a particular coral, Montipora digitata, which is common to the western Pacific Ocean and large swaths of the Great Barrier Reef.The scientists focused on two consecutive spawning seasons: one under normal conditions during 2015 and the other during the global mass coral bleaching event of 2016. Using DNA sequencing, the scientists screened which corals showed potential to shuffle their symbionts and if the change was reflected in gametes. They found that the numbers and types of algal cells differed considerably from one year to the next, as measured in cell densities and photosynthesis output. It's a finding consistent with other research.Montipora digitata coral can package algae in their eggs when they reproduce. In looking at the eggs between the two years, they discovered that rearrangements of the algae communities in the adults were also reflected in the coral's eggs, indicating that they could be passed down to offspring from the parents."To our knowledge, this is the first evidence that shuffled Symbiodiniaceae (symbiont) communities ... can be inherited by offspring and supports the hypothesis that shuffling in microbial communities may serve as a mechanism of rapid coral acclimation to changing environmental conditions," the study said.The process is perhaps similar to how mitochondrial DNA works in humans. In that analog, the mitochondria -- an energy-producing unit inside the cell but outside the nucleus -- shares genetic material with offspring via the mother's egg. However, the researchers have not identified the mechanism for transfer in coral; they plan to answer that mystery in the next study.The findings show coral may be more adaptable than thought, but is it enough?Corals face an enormous challenge as ocean warming is increasing. According to a United Nations report, the world's coral reefs are at the epicenter for climate change impacts and species loss. If the world warms another 0.9 degrees Fahrenheit, which is likely, coral reefs will probably dwindle by 70% to 90%. A gain of 1.8 degrees, the report says, means 99% of the world's coral will be in trouble.In some regions, the threat to coral is already severe. For example, as much as 80% of Caribbean Sea coral has been lost in the past three decades, according to the Smithsonian Institution."Corals have more mechanisms than we thought to deal with climate change, but they're fighting with a tiny sword against a foe that's like a tank," Kenkel said. "Their adaptability may not be enough. They need time so they can adapt."The study authors are Kate M. Quigley at the Australian Institute of Marine Science in Australia; Bette L. Willis at James Cook University in Australia; and Kenkel at the USC Dornsife College.Funding was provided by grants from the U.S. National Science Foundation (#DBI-1401165) and the Australian Research Council (#CE1401000020).
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Extinction
| 2,019 |
September 13, 2019
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https://www.sciencedaily.com/releases/2019/09/190913101432.htm
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Extinction of Icelandic walrus coincides with Norse settlement
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An international collaboration of scientists in Iceland, Denmark and the Netherlands has for the first time used ancient DNA analyses and C14-dating to demonstrate the past existence of a unique population of Icelandic walrus that went extinct shortly after Norse settlement some 1100 years ago. Walrus hunting and ivory trade was probably the principal cause of extinction, being one of the earliest examples of commercially driven overexploitation of marine resources.
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The presence of walruses in Iceland in the past and its apparent disappearance as early as in the Settlement and Commonwealth periods (870-1262 AD) has long puzzled the scientific world. In a study recently published in the journal "Natural History Museum collections provide a remarkable window into the past, which with modern day technology allow us to explore the past effects of human activities and environmental change on species and ecosystems. This can be further put into context by studying the Icelandic Mediaeval literature, historic place names and zooarchaeological sites," explains instigator of the research Hilmar J. Malmquist, Director of the Icelandic Museum of Natural History, Reykjavik, Iceland.The scientists used carbon-14 dating of walrus remains found in Iceland to reveal that walrus inhabited Iceland for thousands of years, but disappeared shortly after the country's settlement around 870 AD by the Norse. DNA was extracted from natural finding sites and archaeological excavations of walrus samples, and compared to data from contemporary walruses, documenting that the Icelandic walrus constituted a genetically unique lineage, distinct from all other historic and contemporary walrus populations in the North Atlantic."Our study provides one of the earliest examples of local extinction of a marine species following human arrival and overexploitation. It further adds to the debate about the role of humans in the extinction of megafauna, supporting a growing body of evidence that wherever humans turn up, the local environment and ecosystem suffers," says Morten Tange Olsen, Assistant Professor at Globe Institute, University of Copenhagen.Walrus ivory was a luxury good in high demand and widely traded across Viking Age and Medieval Europe with beautifully ornamented tusks documented as far away as the Middle East and India. Most examples of trade and human overexploitation and extinction of local marine resources are of much more recent date, such as overfishing, and commercial whaling for the past three centuries or so."We show that already in the Viking Age, more than 1000 years ago, commercial hunting, economic incentives and trade networks were of sufficient scale and intensity to result in significant, irreversible ecological impacts on the marine environment, potentially exacerbated by a warming climate and volcanism. The reliance on marine mammal resources for both consumption and trade has so far been underestimated," says lead author Xénia Keighley, who is completing a PhD at the GLOBE Institute in Copenhagen and the Arctic Centre in Groningen.The research was conducted by Xénia Keighley (University of Copenhagen and University of Groningen), Snæbjörn Pálsson (University of Iceland), Bjarni F. Einarsson (Archaeological Office in Iceland), Aevar Petersen, Meritxell Fernández-Coll (Icelandic Museum of Natural History), Peter Jordan (University of Groningen), Morten Tange Olsen (University of Copenhagen), and Hilmar J. Malmquist (Icelandic Museum of Natural History).
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Extinction
| 2,019 |
September 12, 2019
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https://www.sciencedaily.com/releases/2019/09/190912094709.htm
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Mysterious Jurassic crocodile identified 250 years after fossil find
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A prehistoric crocodile that lived around 180 million years ago has been identified -- almost 250 years after the discovery of it fossil remains.
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A fossil skull found in a Bavarian town in the 1770s has been recognised as the now-extinct species Mystriosaurus laurillardi, which lived in tropical waters during the Jurassic Period.For the past 60 years, it was thought the animal was part of a similar species, known as Steneosaurus bollensis, which existed around the same time, researchers say.Palaeontologists identified the animal by analysing fossils unearthed in the UK and Germany.The team, which included scientists from the University of Edinburgh, also revealed that another skull, discovered in Yorkshire in the 1800s, belongs to Mystriosaurus laurillardi.The marine predator -- which was more than four metres in length -- had a long snout and pointed teeth, and preyed on fish, the team says. It lived in warm seas alongside other animals including ammonites and large marine reptiles, called ichthyosaurs.The discovery of fossils in present-day Germany and the UK shows that the species could easily swim between islands, much like modern saltwater crocodiles, researchers say.The study, led by Naturkunde-Museum Bielefeld in Germany, is published in the journal Sven Sachs, of the Naturkunde-Museum Bielefeld, who led the study, said: "Mystriosaurus looked like a gharial but it had a shorter snout with its nasal opening facing forwards, whereas in nearly all other fossil and living crocodiles the nasal opening is placed on top of the snout."Dr Mark Young, of the University of Edinburgh's School of GeoSciences, who was involved in the study, said: "Unravelling the complex history and anatomy of fossils like Mystriosaurus is necessary if we are to understand the diversification of crocodiles during the Jurassic. Their rapid increase in biodiversity between 200 and 180 million years ago is still poorly understood."
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Extinction
| 2,019 |
September 11, 2019
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https://www.sciencedaily.com/releases/2019/09/190911142802.htm
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Scientists solve lingering mystery of poorly understood frog
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An international team of scientists, led by researchers at McMaster University, has solved a centuries-old mystery of 'Fraser's Clawed Frog', an unusual and elusive species found in West Africa.
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The findings, published today in the journal Two specimens of the frog, with a distinctive combination of four claws on the hind legs as well as small bony protrusions on the roof of their mouths known as vomerine teeth, were collected by British zoologist Louis Fraser in 1852 and housed at the Natural History Museum (NHM) in London.In 1905, Fraser's clawed frog was designated as a distinct species, but its place on the evolutionary tree, geographic distribution, and ecology has since stumped scientists -- due to a lack of genetic samples and poor records of its origin."The ancient condition of the only two specimens available to us posed many challenges for understanding its distinctiveness using DNA and knowing exactly where they came from," explains Ben Evans, lead author of the study and a professor of biology at McMaster University."The accurate identification of species is so important because it allows us to study change in populations, better understand how evolution occurs, and explore the processes that drive diversification, extinction and adaption," he says.The team, which included researchers from the NHM, the Max Planck Institute in Germany and the University of Florida, used sensitive techniques -similar to approaches used to sequence the genomes of Neanderthals -- to sequence the mitochondrial genome from the delicate specimens.In addition, scientists sequenced complete or nearly complete mitochondrial genomes from 29 other By doing so, they determined Fraser's Clawed Frog was indeed distinct from all others. And while it was previously thought to have lived in lowland tropical forests in West Africa, researchers found it actually inhabits the relatively hot and arid regions of northern Cameroon and northern Ghana."Obtaining DNA from specimens that have been preserved in spirit for well over a hundred years is something that has only become achievable in the last few decades. The recent advances in DNA extraction and sequencing are allowing us to revisit specimens and challenge assumptions made in the past," says Jeff Streicher, senior curator of amphibians and reptiles at the NHM.In the summer of 2020, the team plans to travel to Nigeria to continue their efforts to understand biodiversity and genome evolution of African clawed frogs.
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Extinction
| 2,019 |
September 11, 2019
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https://www.sciencedaily.com/releases/2019/09/190911142731.htm
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Reconstructing the evolution of all species
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An evolution revolution has begun after scientists extracted genetic information from a 1.77 million-year-old rhino tooth -- the largest genetic data set this old to ever be confidently recorded.
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Researchers identified an almost complete set of proteins, a proteome, in the dental enamel of the now-extinct rhino and the resulting genetic information is one million years older than the oldest DNA sequenced from a 700,000-year-old horse.The findings by scientists from the Faculty of Health and Medical Sciences, University of Copenhagen, and St John's College, University of Cambridge, are published today in 'For 20 years ancient DNA has been used to resolve questions about the evolution of extinct species, adaptation and human migration but it has limitations. For the first time we have retrieved ancient genetic information which allows us to reconstruct evolution way beyond the usual time limit of DNA preservation', Professor Enrico Cappellini, Associate Professor in Palaeoproteomics at the Globe Institute, University of Copenhagen, and first author on the paper, says.'This new analysis of ancient proteins from dental enamel will start an exciting new chapter in the study of molecular evolution.'For example, the reliance on DNA analysis allowed to genetically track the processes of evolution behind the origins of our species that occurred approximately in the last 400,000 years. However, considering the lineages leading to our species and to the chimp (the living species closest to us) branched apart approximately six to seven million years ago, it means that we currently have no genetic information from more than 90% of the path of evolution that led to us.Accordingly, we still don't know what exactly is the genetic relation between us and, for example, Homo erectus -- the oldest known species of humans to have had modern human-like body proportions -, or between us and the Australopithecus group of species, which includes the iconic fossil commonly referred to as Lucy.Ancient protein sequencing, based on a ground-breaking technology called mass spectrometry, has now been able to retrieve genetic information from a 1.77 million year old Stephanorhinus -- an extinct rhinoceros which lived in Eurasia during the Pleistocene. The researchers extracted protein remains of dental enamel from a fossil tooth, which was discovered in Dmanisi, Georgia, and used mass spectrometry to sequence the ancient proteins and retrieve genetic information previously unobtainable using DNA sequencing.Tooth enamel is the hardest material present in mammal body. In this study researchers discovered that the set of proteins it contains lasts longer than DNA and is genetically more informative than collagen, the only other ancient protein so far retrieved in fossils older than one million year.Ultimately, mass spectrometry-based ancient protein sequencing expands the possibilities of retrieving reliable and rich genetic information from mammal fossils to those which are millions, rather than just thousands, of years old.'With the new, protein-sequencing based method the possibilities of genetic information have been stretched beyond ancient DNA', Professor and co-corresponding author, Jesper Velgaard Olsen from the Novo Nordisk Foundation Center for Protein Research explains.'Basically, this approach can tell us not only the species and the gender of an ancient fossil, but we can also draw an evolutionary line -- all from a single tooth', he says. 'Dental enamel is extremely abundant and it is highly durable, which is why a high proportion of fossil records are teeth', Enrico Cappellini adds.'We have been able to find a way to retrieve genetic information that is more informative and reliable than any other source of comparable age before, and it's from a material that is abundant in the fossil records so the potential of the application of this approach is extensive.'The sequencing of the ancient proteome from the Dmanisi Stephanorhinus fossil has led the researchers to integrate it in the evolutionary tree including other extinct and extant rhinoceros species and to define its genetic relation with them, lead author on the paper Professor Eske Willerslev explains. Eske Willerslev holds positions at St John's College, University of Cambridge, and is director of The Lundbeck Foundation Centre for GeoGenetics at the University of Copenhagen.'There are extinct species of early humans that we haven't been able to get any DNA from -- species like Homo Erectus. The remains we have are too old and too poorly preserved for the DNA to survive', he says.'This research is a game-changer that opens up a lot of opportunities for further evolutionary studies in terms of humans as well as mammals. It will revolutionise the methods of investigating evolution based on molecular markers and it will open a complete new field of ancient molecular studies.'This rearranging of the evolutionary lineage of a single species may seem like a small adjustment but identifying changes in numerous extinct mammals and humans could lead to massive shifts in our understanding of the way animal life has evolved. The team of scientists are already implementing the findings in their current research.The discovery could enable scientists across the globe to collect the genetic data of ancient fossils and to build a bigger, more accurate picture of the evolution of hundreds of species including our own.
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Extinction
| 2,019 |
September 11, 2019
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https://www.sciencedaily.com/releases/2019/09/190911142721.htm
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Digital records of preserved plants and animals change how scientists explore the world
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There's a whole world behind the scenes at natural history museums that most people never see. Museum collections house millions upon millions of dinosaur bones, pickled sharks, dried leaves, and every other part of the natural world you can think of -- more than could ever be put on display. Instead, these specimens are used in research by scientists trying to understand how different kinds of life evolved and how we can protect them. And a new study in
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When digitized, information about what each museum specimen is and where it's from becomes part of a repository called a biodiversity database. In these databases, data on individual organisms, entire populations, and whole ecosystems is now free and accessible. Scientists are beginning to explore hundreds of years' worth of information on organisms and ecosystems simply by going online. "It's an interesting time for biodiversity data and scientific data more broadly," says Joan Damerow, a post-doctoral researcher at the Field Museum and the paper's first author. "The field is growing and people are becoming more aware of the importance of making data free to everyone."With decades of data available for an animal or plant species, scientists can track what has changed over time and tell a story about a species. A group of researchers, led by Field Museum scientists and researchers from the Florida Museum of Natural History and the Universidad de Navarra, decided to determine exactly how these extensive libraries were being used by scientists to tell stories about animals, ecosystems, and other topics. "In the last 10 years, there has been a massive effort by global institutions to digitize decades' worth of data," says Rüdiger Bieler, curator of invertebrates at the Field Museum. "While a single shell or insect in a collection may not tell a story, these libraries of data create new opportunities to study what is happening to populations of animals over time."Using keywords that indicated the use of a biodiversity database, the researchers examined the full text of hundreds of published papers. "We wanted to look in depth at specifics in the text, including how people are citing databases, how they're taking data errors into account, and what subjects they are studying." says Damerow, lead author. "We found that there's no efficient or automated way to sort through the text of hundreds of papers at this stage?we had to do it manually."The researchers were able to see which digital records got the most use. Out of all groups of organisms, biodiversity databases are most commonly used to study plants. Plants are a broad and diverse group, so it may simply take much more research, and many more papers, to classify them and study their populations.On the other hand, the researchers found that not as many scientists published papers using data from insects. A much smaller proportion of insect specimens have been digitized, compared to plants and vertebrates. That might be because of bugs' small sizes and the vast number of them in museum collections -- they're often pinned or preserved by the thousands in jars of alcohol, making it daunting to convert each individual specimen's physical label into a digital record that can be searched on a database. Insect population health can be an indicator of ecosystem health, so digitizing and analyzing insect data is important for ecological and conservation research. "It was interesting to me to confirm that vertebrates have more existing online records than invertebrates," says Petra Sierwald, an associate curator of insects, arachnids, and myriapods at the Field Museum and one of the paper's authors. "Because this showed we still have far to go with invertebrate digitization, it renewed my enthusiasm for digitizing insect specimens."Damerow and her colleagues found that scientists most often use biodiversity databases to find out where different species are found, how many species are present in a region, and how organisms are related to each other. This kind of information helps scientists track species populations, migration patterns, and the spread of disease -- crucial information for conservation and public health research. For instance, scientists can see if animals that normally live in cold regions are retreating farther north to deal with climate change.As the mechanisms to accurately record and explore information improve and become standardized, the ability to make hypotheses and predictions about what has happened or will happen to animal and plant populations will become even more powerful."With the biodiversity loss in many ecosystems right now, it's critical to document where and with what abundance different species exist in an environment," says Damerow. "The biodiversity crisis is making it more urgent that we have a place where information on these ecosystems is easily accessible. As species' populations decline, we need efficient methods that help focus conservation efforts and resources."
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Extinction
| 2,019 |
September 9, 2019
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https://www.sciencedaily.com/releases/2019/09/190909160102.htm
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Rocks at asteroid impact site record first day of dinosaur extinction
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When the asteroid that wiped out the dinosaurs slammed into the planet, the impact set wildfires, triggered tsunamis and blasted so much sulfur into the atmosphere that it blocked the sun, which caused the global cooling that ultimately doomed the dinos.
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That's the scenario scientists have hypothesized. Now, a new study led by The University of Texas at Austin has confirmed it by finding hard evidence in the hundreds of feet of rocks that filled the impact crater within the first 24 hours after impact.The evidence includes bits of charcoal, jumbles of rock brought in by the tsunami's backflow and conspicuously absent sulfur. They are all part of a rock record that offers the most detailed look yet into the aftermath of the catastrophe that ended the Age of Dinosaurs, said Sean Gulick, a research professor at the University of Texas Institute for Geophysics (UTIG) at the Jackson School of Geosciences."It's an expanded record of events that we were able to recover from within ground zero," said Gulick, who led the study and co-led the 2016 International Ocean Discovery Program scientific drilling mission that retrieved the rocks from the impact site offshore of the Yucatan Peninsula. "It tells us about impact processes from an eyewitness location."The research was published in the Most of the material that filled the crater within hours of impact was produced at the impact site or was swept in by seawater pouring back into the crater from the surrounding Gulf of Mexico. Just one day deposited about 425 feet of material -- a rate that's among the highest ever encountered in the geologic record. This breakneck rate of accumulation means that the rocks record what was happening in the environment within and around the crater in the minutes and hours after impact and give clues about the longer-lasting effects of the impact that wiped out 75% of life on the planet.Gulick described it as a short-lived inferno at the regional level, followed by a long period of global cooling."We fried them and then we froze them," Gulick said. "Not all the dinosaurs died that day, but many dinosaurs did."Researchers estimate the asteroid hit with the equivalent power of 10 billion atomic bombs of the size used in World War II. The blast ignited trees and plants that were thousands of miles away and triggered a massive tsunami that reached as far inland as Illinois. Inside the crater, researchers found charcoal and a chemical biomarker associated with soil fungi within or just above layers of sand that shows signs of being deposited by resurging waters. This suggests that the charred landscape was pulled into the crater with the receding waters of the tsunami.Jay Melosh, a Purdue University professor and expert on impact cratering, said that finding evidence for wildfire helps scientists know that their understanding of the asteroid impact is on the right track."It was a momentous day in the history of life, and this is a very clear documentation of what happened at ground zero," said Melosh, who was not involved with this study.However, one of the most important takeaways from the research is what was missing from the core samples. The area surrounding the impact crater is full of sulfur-rich rocks. But there was no sulfur in the core.That finding supports a theory that the asteroid impact vaporized the sulfur-bearing minerals present at the impact site and released it into the atmosphere, where it wreaked havoc on the Earth's climate, reflecting sunlight away from the planet and causing global cooling. Researchers estimate that at least 325 billion metric tons would have been released by the impact. To put that in perspective, that's about four orders of magnitude greater than the sulfur that was spewed during the 1883 eruption of Krakatoa -- which cooled the Earth's climate by an average of 2.2 degrees Fahrenheit for five years.Although the asteroid impact created mass destruction at the regional level, it was this global climate change that caused a mass extinction, killing off the dinosaurs along with most other life on the planet at the time."The real killer has got to be atmospheric," Gulick said. "The only way you get a global mass extinction like this is an atmospheric effect."The research was funded by a number of international and national support organizations, including the National Science Foundation.
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Extinction
| 2,019 |
September 9, 2019
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https://www.sciencedaily.com/releases/2019/09/190909113028.htm
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Identity crisis for fossil beetle helps rewrite beetle family tree
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There are more different kinds of beetle than just about any other kind of animal -- scientists have described about 5,800 different species of mammals, compared with nearly 400,000 species of beetles. Of those 400,000 kinds of beetles, more than 64,000 species are members of the rove beetle family,
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The beetle at the center of this mix-up, about the size of Franklin D. Roosevelt's nose on the U.S. dime, is Until 2012, the only public information on the fossils was two images, published in 1996 and 2005, but no formal description. Anyone who didn't have direct access to the fossils of the species could only make guesses about its placement in the tree of life based on those photos.So, when a formal description of the beetle was finally published, beetle scientists around the world were excited to read it."When "I happened to be at the museum when I first read the paper, so I went and looked through the specimens in our collection to compare," said Alfred Newton, also a Field Museum scientist and paper author. His hunch was that this beetle might be more closely related to Hydroscaphidae, a living family of miniature insects known as skiff beetles, placed in a different suborder from rove beetles.Across the Atlantic, Martin Fikáček recalled a similar feeling upon comparing the description and photos with the classification of One of the clues that Another hallmark of Given the hidden mandibles, distinct antennal shape, and other features, including "paratergites" -- little plates on the sides of most Thanks to the power of the internet, the scientists were able to collaborate freely and quickly across four continents. "The international collaboration that occurred here was really important to the success of the study," said Shûhei Yamamoto, a Field Museum scientist and paper author who studies As the group's hunch turned to a theory, then a study, then a formal analysis, the tests they ran showed Misclassification of extinct species happens all the time in science, for a variety of reasons.For one, fossils can be extremely difficult to decipher. Since compression fossils like Lack of comparative data also causes problems for researchers. Not only are many characteristics of the insects lost in fossils, but until 2011, the large amount of data used here to test "Our analysis made use of a huge data set of morphological characters of beetles gathered for the 'Beetle Tree of Life' [BToL] project," says Thayer. "That project was really crucial to our analysis and provided a framework upon which we were able to analyze Testing and revising the placement of living things in the tree of life is like working on a huge sudoku puzzle with contributors from all over the world. You have methods to figure out where the numbers should go, but if they're incorrectly placed, you only know -- eventually -- based on their relationships to the surrounding numbers. If you carry on with the puzzle for too long with an incorrect placement, numbers filled in after the fact might also be incorrect. Revisiting For the "The re-classification of At a time in the Earth's history when life was still recovering after a mass extinction, the appearance of "Throughout history, beetles have survived conditions that other animals have not," says Fikáček. "As we study these insects, we might reveal some secret to evolutionary success that beetles possess."
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Extinction
| 2,019 |
August 30, 2019
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https://www.sciencedaily.com/releases/2019/08/190830150801.htm
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Oxygen depletion in ancient oceans caused major mass extinction
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Late in the prehistoric Silurian Period, around 420 million years ago, a devastating mass extinction event wiped 23 percent of all marine animals from the face of the planet.
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For years, scientists struggled to connect a mechanism to this mass extinction, one of the 10 most dramatic ever recorded in Earth's history. Now, researchers from Florida State University have confirmed that this event, referred to by scientists as the Lau/Kozlowskii extinction, was triggered by an all-too-familiar culprit: rapid and widespread depletion of oxygen in the global oceans.Their study, published today in the journal Unlike other famous mass extinctions that can be tidily linked to discrete, apocalyptic calamities like meteor impacts or volcanic eruptions, there was no known, spectacularly destructive event responsible for the Lau/Kozlowskii extinction."This makes it one of the few extinction events that is comparable to the large-scale declines in biodiversity currently happening today, and a valuable window into future climate scenarios," said study co-author Seth Young, an assistant professor in the Department of Earth, Ocean and Atmospheric Science.Scientists have long been aware of the Lau/Kozlowskii extinction, as well as a related disruption in Earth's carbon cycle during which the burial of enormous amounts of organic matter caused significant climate and environmental changes. But the link and timing between these two associated events -- the extinction preceded the carbon cycle disruption by more than a hundred thousand years -- remained stubbornly opaque."It's never been clearly understood how this timing of events could be linked to a climate perturbation, or whether there was direct evidence linking widespread low-oxygen conditions to the extinction," said FSU doctoral student Chelsie Bowman, who led the study.To crack this difficult case, the team employed a pioneering research strategy.Using advanced geochemical methods including thallium isotope, manganese concentration, and sulfur isotope measurements from important sites in Latvia and Sweden, the FSU scientists were able to reconstruct a timeline of ocean deoxygenation with relation to the Lau/Kozlowskii extinction and subsequent changes to the global carbon cycle.The team's new and surprising findings confirmed their original hypothesis that the extinction record might be driven by a decline of ocean oxygenation. Their multiproxy measurements established a clear connection between the steady creep of deoxygenated waters and the step-wise nature of the extinction event -- its start in communities of deep-water organisms and eventual spread to shallow-water organisms.Their investigations also revealed that the extinction was likely driven in part by the proliferation of sulfidic ocean conditions."For the first time, this research provides a mechanism to drive the observed step-wise extinction event, which first coincided with ocean deoxygenation and was followed by more severe and toxic ocean conditions with sulfide in the water column," Bowman said.With the oxygen-starved oceans of the Lau/Kozlowskii extinction serving as an unnerving precursor to the increasingly deoxygenated waters observed around the world today, study co-author Jeremy Owens, an assistant professor in the Department of Earth, Ocean and Atmospheric Science, said that there are still important lessons to be learned from ecological crises of the distant past."This work provides another line of evidence that initial deoxygenation in ancient oceans coincides with the start of extinction events," he said. "This is important as our observations of the modern ocean suggest there is significant widespread deoxygenation which may cause greater stresses on organisms that require oxygen, and may be the initial steps towards another marine mass extinction."
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Extinction
| 2,019 |
August 30, 2019
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https://www.sciencedaily.com/releases/2019/08/190830112815.htm
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What if we paid countries to protect biodiversity?
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Researchers from Sweden, Germany, Brazil and the USA have developed a financial mechanism to support the protection of the world's natural heritage. In a recent study, they developed three different design options for an intergovernmental biodiversity financing mechanism. Asking what would happen if money was given to countries for providing protected areas, they simulated where the money would flow, what type of incentives this would create -- and how these incentives would align with international conservation goals.
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After long negotiations, the international community has agreed to safeguard the global ecosystems and improve on the status of biodiversity. The global conservation goals for 2020, called the Aichi targets, are an ambitious hallmark. Yet, effective implementation is largely lacking. Biodiversity is still dwindling at rates only comparable to the last planetary mass extinction. Additional effort is required to reach the Aichi targets and even more so to halt biodiversity loss."Human well-being depends on ecological life support. Yet, we are constantly losing biodiversity and therefore the resilience of ecosystems. At the international level, there are political goals, but the implementation of conservation policies is a national task. There is no global financial mechanism that can help nations to reach their biodiversity targets," says lead author Nils Droste from Lund University, Sweden.Brazil has successfully implemented Ecological Fiscal Transfer systems that compensate municipalities for hosting protected areas at a local level since the early 1990's. According to previous findings, such mechanisms help to create additional protected areas. The international research team has therefore set out to scale this idea up to the global level where not municipalities but nations are in charge of designating protected areas. They developed and compared three different design options:An ecocentric model: where only protected area extent per country counts -- the bigger the protected area, the better;A socio-ecological model: where protected areas and Human Development Index count, adding development justice to the previous model;An anthropocentric model: where population density is also considered, as people benefit locally from protected areas.The socio-ecological design was the one that proved to be the most efficient. The model provided the highest marginal incentives -- that is, the most additional money for protecting an additional percent of a country's area -- for countries that are the farthest from reaching the global conservation goals. The result surprised the researchers."While we developed the socio-ecological design with a fairness element in mind, believing that developing countries might be more easily convinced by a design that benefits them, we were surprised how well this particular design aligns with the global policy goals," says Nils Droste."It would most strongly incentivize additional conservation action where the global community is lacking it the most," he adds.As the study was aimed at providing options, not prescriptions for policy makers, the study did not detail who should be paying or how large the fund should exactly be. Rather, it provides a yet unexplored option to develop a financial mechanism for biodiversity conservation akin to what the Green Climate Fund is for climate change."We know that we need to change land use in order to preserve biodiversity. Protecting land from degradation and providing healthy ecosystems, clean air or clean rivers is a function of the state. Giving a financial reward to governments for such public ecosystem services will ease the provision of corresponding conservation efforts and will help to put this on the agenda," concludes Nils Droste.
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Extinction
| 2,019 |
August 30, 2019
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https://www.sciencedaily.com/releases/2019/08/190830112813.htm
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Amazon deforestation has a significant impact on the local climate in Brazil
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The loss of forest cover in the Amazon has a significant impact on the local climate in Brazil, according to a new study.
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The UN Environment Programme has said warned that the Amazon wildfires threaten ." ..this precious natural resource..." and that the forest helps mitigate the effects of climate change.Insight into the effects of deforestation in the Amazon -- and the way it can intensify climate change, particularly at a local level -- has been published open access in the journal Using satellite data, Jess Baker and Professor Dominick Spracklen from the University of Leeds, evaluated the climatic consequences of deforestation in the Amazon between 2001 and 2013.They found that deforestation causes the local climate to warm -- and that warming intensified as the severity of deforestation increased.Intact forests in the region, with less than 5% canopy loss, had the most climate stability over the ten years, showing only small increases in temperature.Areas that had tree cover reduced to below 70% warmed 0.44°C more than neighbouring intact forests during the study period.The differences between intact and disturbed forests were most pronounced during the driest part of the year, when temperature increases of up to 1.5°C were observed in areas affected by severe deforestation. This increase is additional to global temperature rises driven by climate change.Study co-author Jess Baker from the School of Earth and Environment at Leeds said: "The Amazon wildfires have reminded us all of the important role that forests play in our global systems. But it cannot be overlooked that intact Amazon forests are also crucially important for Brazil's own local climate."A healthy intact Amazon forest helps regulate the local climate and can even act as a buffer to the warming effects of climate change, compared with disturbed forests."Study co-author Dominick Spracklen, Professor of Biopshere-Atmosphere Interactions at Leeds said: "Deforestation decreases the amount of water emitted to the atmosphere from the forest through a process called evapotranspiration."Evapotranspiration can be thought of as the forest 'sweating'; when the moisture emitted by the forests evaporates it cools the local climate. Deforestation reduces evapotranspiration, taking away this cooling function and causing local temperatures to rise."As temperatures rise this increases drought stress and makes forests more susceptible to burning."
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Extinction
| 2,019 |
August 29, 2019
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https://www.sciencedaily.com/releases/2019/08/190829101057.htm
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Plant diversity and endemism in China: Unreachable locations and diverse microclimates
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A new issue of the scholarly, open-access and peer-reviewed journal
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In China, biodiversity-rich landscapes vary from the dry Northwest region, through the surrounded by massive mountain ranges of the Qinghai-Tibet Plateau, to the tropical and subtropical southern China. The combination of remote and hard to reach mountain areas and diverse microclimates promises high levels of endemism."With extended collaboration among Chinese scientists and coordination of networks on plant conservation and taxonomy across China, we synthesize a special issue entitled "Revealing the plant diversity in China's biodiversity hotspots," to present the latest findings by Chinese botanists, and to update knowledge of the flora for China and adjacent countries," explained De-Zhu Li, professor of botany at Kunming Institute of Botany (KIB), Chinese Academy of Sciences (CAS), in the editorial.Among the newly described species, four new members of the African violet family were found from a subtropical forest in Yunnan province in southern China, discovered by researchers from Xishuangbanna Tropical Botanical Garden, CAS and their collaborators. Half of them were found only from a sole population and require further botanical examinations to deploy the conservation priorities, remark the scientists.In another paper, scientists Yun-Feng Huang and Li-Na Dong and Wei-Bin Xu, representatives of Guangxi Institute of Botany, revealed the discovery of a new species from the primrose family. Found nowhere outside the limestone areas in Liucheng county (Guangxi, China), this rare plant species is currently facing serious threats of extinction because of the fragility and sensitivity of its habitat to the environmental changes associated with the rapid economic development of China.Another team from the Guizhou University of Traditional Chinese Medicine and KIB describes a new representative of the parachute flowers. "More conservation efforts are needed in this region to counteract the increasing anthropogenic disturbance and destruction," state the leading authors from KIB, who discovered a new species of orchid in the Eastern Himalaya biodiversity hotspot.The special issue features the description of additional two orchid species, discovered in Motuo, located at the Himalayan border between China, Myanmar and India. The region is well known for its vertical vegetation system, varying from tropical forest to permanent glaciers. Ji-Dong Ya and Cheng Liu from the KIB and Xiao-Hua Jin from the Institute of Botany, CAS underline that the difficult access to the area allows the thriving and diversification of plants.
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Extinction
| 2,019 |
August 29, 2019
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https://www.sciencedaily.com/releases/2019/08/190829081352.htm
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Extreme mangrove corals found on the Great Barrier Reef
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The first documented discovery of "extreme corals" in mangrove lagoons around Australia's Great Barrier Reef is yielding important information about how corals deal with environmental stress, scientists say. Thirty four species of coral were found to be regularly exposed to extreme low pH, low oxygen and highly variable temperature conditions making two mangrove lagoons on the Woody Isles and Howick Island potential "hot-spots" of coral resilience.
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Although coral cover was typically low and somewhat patchy in the lagoon waters, DECRA Research Fellow Dr Emma Camp, from the University of Technology Sydney (UTS) said the discovery was important because it "provides novel information on the mechanisms that support coral resilience to stressors such as climate change and pollution.""This highlights the need to study environments that would usually be considered unfavourable to corals in order to understand how stress tolerance in corals works."There is a lot we don't know. For example are these extreme corals already at their limit, can they survive more stress, if we transplant them to more stable environments will they maintain their stress tolerance?," Dr Camp said.Dr Camp is no stranger to searching for corals in unexpected places. Camp and colleagues were the first to recognise that the corals they found in the murky lagoon waters of New Caledonia could provide answers to help support coral reef survival in the face of unprecedented global coral reef bleaching events.With the support of Wavelength Reef Charters and funding from Waitt Foundation/National Geographic the research team surveyed 250km of the northern GBR visiting eight lagoons located on five off-shore islands.Analysis of coral samples showed that a combination of photosynthetic "strategy" (physiological plasticity) and microbial diversity supports coral survival. However with survival comes a trade-off -- the corals had reduced calcification rates, meaning they are growing more slowly than their reef counterparts.Team Leader of the UTS Climate Change Cluster Future Reefs Research Group, Associate Professor David Suggett, said the study outcomes were important "as we look for innovative ways to support coral survival into the future.""It's likely these mangrove lagoon corals have the best chance to persist into the future given that they are already conditioned to the complex interaction of warmer waters, ocean acidification and deoxygenation predicted for reefs under climate change" he said.Having just discovered these "tough" examples of one of nature's most extraordinary symbiotic relationships the researchers say there is a need to help coral survival by giving enhanced protection to these special places on the Great Barrier Reef where corals persist into mangrove lagoons.The researchers say that because these habitats carry previously unrecognised ecosystem service value for corals, spanning from acting as places of refuge to stress preconditioning, "this makes their protection even more important."
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Extinction
| 2,019 |
August 28, 2019
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https://www.sciencedaily.com/releases/2019/08/190828180437.htm
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Ancient die-off greater than the dinosaur extinction
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Clues from Canadian rocks formed billions of year ago reveal a previously unknown loss of life even greater than that of the mass extinction of the dinosaurs 65 million years ago, when Earth lost nearly three-quarters of its plant and animal species.
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Rather than prowling animals, this die-off involved miniscule microorganisms that shaped the Earth's atmosphere and ultimately paved the way for those larger animals to thrive."This shows that even when biology on Earth is comprised entirely of microbes, you can still have what could be considered an enormous die-off event that otherwise is not recorded in the fossil record," said Malcolm Hodgskiss, co-lead author of a new study published in Proceedings of the National Academy of Sciences.Because this time period preceded complex life, researchers cannot simply dig up fossils to learn what was living 2 billion years ago. Even clues left behind in mud and rocks can be difficult to uncover and analyze.Instead, the group turned to barite, a mineral collected from the Belcher Islands in Hudson Bay, Canada, that encapsulates a record of oxygen in the atmosphere. Those samples revealed that Earth experienced huge changes to its biosphere -- the part of the planet occupied by living organisms -- ending with an enormous drop in life approximately 2.05 billion years ago that may also be linked to declining oxygen levels."The fact that this geochemical signature was preserved was very surprising," Hodgskiss said. "What was especially unusual about these barites is that they clearly had a complex history."Looking at the Earth's productivity through ancient history provides a glimpse into how life is likely to behave over its entire existence -- in addition to informing observations of atmospheres on planets outside our solar system."The size of the biosphere through geologic time has always been one of our biggest questions in studying the history of the Earth," said Erik Sperling, an assistant professor of geological sciences at Stanford who was not involved with the study. "This new proxy demonstrates how interlinked the biosphere and levels of oxygen and carbon dioxide in the atmosphere are."This relationship between the proliferation of life and atmospheric oxygen has given researchers new evidence of the hypothesized "oxygen overshoot." According to this theory, photosynthesis from ancient microorganisms and the weathering of rocks created a huge amount of oxygen in the atmosphere that later waned as oxygen-emitting organisms exhausted their nutrient supply in the ocean and became less abundant. This situation is in contrast to the stable atmosphere we know on Earth today, where the oxygen created and consumed balances out. The researchers' measurements of oxygen, sulfur and barium isotopes in barite support this oxygen overshoot hypothesis.The research helps scientists hone their estimates of the size of the oxygen overshoot by revealing the significant biological consequences of oxygen levels above or below the capacity of the planet."Some of these oxygen estimates likely require too many microorganisms living in the ocean in Earth's past," said co-lead author Peter Crockford, a postdoctoral researcher at the Weizmann Institute of Science and Princeton University. "So we can now start to narrow in on what the composition of the atmosphere could have been through this biological angle."The research was supported by Stanford University McGee and Compton Grants, the Northern Scientific Training Program, NSERC, National Geographic, the American Philosophical Society, Geological Society of America and the Agouron Institute.
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Extinction
| 2,019 |
August 28, 2019
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https://www.sciencedaily.com/releases/2019/08/190828140106.htm
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Climate change, human activity lead to nearshore coral growth decline
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New research from the University of North Carolina at Chapel Hill compares the growth rates between nearshore and offshore corals in the Belize Mesoamerican Barrier Reef System, the world's second-largest reef system. While nearshore corals have historically grown faster than those offshore, over the past decade there was a decline in the growth rates of two types of nearshore corals, while offshore coral growth rates in the same reef system stayed the same.
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Coral reefs are a critical source of food, income and storm protection for millions of people worldwide. Nearshore corals grow in warmer and more nutrient-rich waters than their offshore counterparts and, because of their warmer temperatures, are believed to give a glimpse into the coral reefs of the future. This growth decline leads researchers to believe that any previous environmental advantage that came from corals being located closer to shore has now diminished. This is likely due to climate change and human activities, like coastal development that introduces excess sediment and nutrients to the water, subjecting corals close to shore to higher levels of stress. The findings also suggest that over time climate change will slow the growth of nearshore and offshore corals throughout the world."This research leaves us with troubling questions, like whether or not corals will be able to adapt to future conditions, and, if not, how that will impact the health and well-being of the millions of people around the world who rely on reefs for their food, income and protection from storms," said Justin Baumann, postdoctoral researcher in marine sciences and biology at the University of North Carolina at Chapel Hill. "Since we don't know the answer to these questions, it remains crucial that we carefully manage and protect reefs so that they will have the best possible chance to acclimate, adapt, and, hopefully, survive the impacts of climate change."Baumann is lead author of the paper, which was published in The research team looked at the relationship between growth rates and specific acute stress events, such as coral bleaching. Coral bleaching happens when corals become stressed by pollution or increased ocean temperature and the colorful algae living inside of coral tissue are expelled, causing the coral to turn white. They found that while coral bleaching events can slow the growth of coral, the long-term declines in nearshore coral growth appear to be driven by the chronic stress of rising water temperatures due to climate change combined with increasing land-based stresses like development along the coast.The study evaluated corals that were located along a 300-kilometer stretch of the Belize portion of the Mesoamerican Barrier Reef System. The nearshore coral reefs were within 10 kilometers of Belize's coast and the offshore coral reefs were 30-60 kilometers away from mainland Belize. Scuba divers collected 124 coral core samples for the study. A coral's core has growth bands that show its age, similar to the rings on a tree. The cores were taken from 19 sites, providing a sample size large enough to represent the entire reef system.In the lab, the research team performed CT scans on the cores to measure the yearly vertical growth rate of the coral skeletons for each core. Reefs that have lower vertical growth rates are expected to be less diverse and complex. They also offer less protection to the shoreline and provide less area for fish and other invertebrates to live. The extent to which these reef changes will harm the communities that rely on them for food, income and protection against storms is yet to be seen."Local action to mitigate stress from coastal development and global action to reduce greenhouse gas emissions will both be necessary to ensure a sustainable future for both nearshore and offshore coral reefs," said Baumann.
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Extinction
| 2,019 |
August 26, 2019
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https://www.sciencedaily.com/releases/2019/08/190826104844.htm
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Beaver reintroduction key to solving freshwater biodiversity crisis
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Reintroducing beavers to their native habitat is an important step towards solving the freshwater biodiversity crisis, according to experts at the University of Stirling.
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New research from the Faculty of Natural Sciences has provided further support to previous work that has shown beavers have an important impact on the variety of plant and animal life.The latest study, led by Dr Alan Law and Professor Nigel Willby, found that the number of species only found in beaver-built ponds was 50 percent higher than other wetlands in the same region.Dr Law, Lecturer in Biological and Environmental Sciences, said: "Beavers make ponds that, at first glance, are not much different from any other pond. However, we found that the biodiversity -- predominantly water plants and beetles -- in beaver ponds was greater than and surprisingly different from that found in other wetlands in the same region."Our results also emphasise the importance of natural disturbance by big herbivores -- in this case, tree felling, grazing and digging of canals by beavers -- in creating habitat for species which otherwise tend to be lost."Reintroducing beavers where they were once native should benefit wider biodiversity and should be seen as an important and bold step towards solving the freshwater biodiversity crisis."Beavers are one of the only animals that can profoundly engineer the environment that they live in -- using sticks to build dams across small rivers, behind which ponds form. Beavers do this to raise water levels to avoid predators, such as wolves and bears: however, numerous other plants and animals also benefit from their work.The research team surveyed water plants and beetles in 20 wetlands in a small area of southern Sweden -- 10 created by beavers and 10 that were not -- to understand whether beavers might provide a solution to the current biodiversity crisis by creating novel habitats.Professor Willby added: "The loss of large mammals from modern landscapes is a global conservation concern. These animals are important in their own right, but our research emphasises the added biodiversity benefits that go with them."We are best reminded of this effect when large herbivores, such as beavers, are reintroduced to places where they have been lost."This research follows the team's 2018 study that found that 33 percent more plant species and 26 percent more beetles were living in wetlands created by beavers, compared to those that were not. Another previous study, from 2017, showed that -- over a period of 12 years -- local plant richness in a Tayside wetland rose by 46 percent following the introduction of beavers. They created 195 metres of dams, 500 metres of canals and a hectare of ponds.
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Extinction
| 2,019 |
August 15, 2019
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https://www.sciencedaily.com/releases/2019/08/190815143212.htm
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Extinct Caribbean bird yields DNA after 2,500 years in watery grave
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Scientists have recovered the first genetic data from an extinct bird in the Caribbean, thanks to the remarkably preserved bones of a Creighton's caracara from a flooded sinkhole on Great Abaco Island.
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Studies of ancient DNA from tropical birds have faced two formidable obstacles. Organic material quickly degrades when exposed to heat, light and oxygen. And birds' lightweight, hollow bones break easily, accelerating the decay of the DNA within.But the dark, oxygen-free depths of a 100-foot blue hole known as Sawmill Sink provided ideal preservation conditions for the bones of Florida Museum of Natural History postdoctoral researcher Jessica Oswald extracted and sequenced genetic material from a 2,500-year-old "I was super excited. I would have been happy to get that amount of coverage from a fresh specimen," said Oswald, lead author of a study describing the work and also a postdoctoral researcher at the University of Nevada, Reno. "Getting DNA from an extinct bird in the tropics is significant because it hasn't been successful in many cases or even tried."The mitochondrial genome showed that At least six species of caracara once cleaned carcasses and picked off small prey in the Caribbean. But the retreat of glaciers 15,000 years ago and the resulting rise in sea levels triggered extinctions of many birds, said David Steadman, Florida Museum curator of ornithology."This species would still be flying around if it weren't for humans," Steadman said. "We're using ancient DNA to study what should be modern biodiversity."Today, the islands host only a fraction of the wildlife that once flourished in the scrubland, forests and water. But blue holes like Sawmill Sink can offer a portal into the past. Researchers have collected more than 10,000 fossils from the sinkhole, representing nearly 100 species, including crocodiles, tortoises, iguanas, snakes, bats and more than 60 species of birds.Sawmill Sink's rich store of fossils was discovered by cave diver Brian Kakuk in 2005 in his quest for horizontal passages in the limestone. The hole was not a popular diving spot: Thirty feet below the surface lay a 20-foot-thick layer of saturated hydrogen sulfide, an opaque mass that not only smells of rotten egg, but also reacts with the freshwater above it to form sulfuric acid, which causes severe chemical burns.After multiple attempts, Kakuk, outfitted with a rebreather system and extra skin protection, punched through the hydrogen sulfide. His lamp lit up dozens of skulls and bones on the blue hole's floor.Soon after, Kakuk and fellow cave diver Nancy Albury began an organized diving program in Sawmill Sink."This was found by someone who recognized what it was and never moved anything until it was all done right," Steadman said.Though the hydrogen sulfide layer presented a foul problem for divers, it provided excellent insulation for the fossils below, blocking UV light and oxygen from reaching the lower layer of water. Among the crocodile skulls and tortoise shells were the "For birds, having an entire head of an extinct species from a fossil site is pretty mind-blowing," Oswald said. "Because all the material from the blue hole is beautifully preserved, we thought at least some DNA would probably be there."Since 2017, Oswald has been revitalizing the museum's ancient DNA laboratory, testing methods and developing best practices for extracting and analyzing DNA from fossils and objects that are hundreds to millions of years old.Ancient DNA is a challenging medium because it's in the process of degradation. Sometimes only a minute quantity of an animal's original DNA -- or no DNA at all -- remains after bacteria, fungi, light, oxygen, heat and other environmental factors have broken down an organism."With ancient DNA, you take what you can get and see what works," Oswald said. "Every bone has been subjected to slightly different conditions, even relative to other ones from the same site."To maximize her chance of salvaging genetic material, Oswald cleans a bone, freezes it with liquid nitrogen and then pulverizes it into powder with a rubber mallet."It's pretty fun," she said.While previous studies required large amounts of bone, Oswald's caracara work showed ancient DNA could be successfully recovered at a smaller scale."This puts an exclamation point on what's possible with ancient DNA," said Robert Guralnick, Florida Museum curator of bioinformatics. "We have new techniques for looking at the context of evolution and extinction. Beyond the caracara, it's cool that we have an ancient DNA lab that's going to deliver ways to look at questions not only from the paleontological perspective, but also at the beginnings of a human-dominated planet."Steadman, who has spent decades researching modern and extinct biodiversity in the Caribbean, said some questions can only be answered with ancient DNA."By understanding species that weren't able to withstand human presence, it helps us better appreciate what we have left -- and not just appreciate it, but understand that when these species evolved, there were a lot more things running and flying around than we have today."Other co-authors are Julia Allen of the University of Nevada, Reno; Kelsey Witt of the University of California, Merced; Ryan Folk of the Florida Museum and Nancy Albury of the National Museum of the Bahamas.
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Extinction
| 2,019 |
August 14, 2019
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https://www.sciencedaily.com/releases/2019/08/190814090712.htm
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Unique dietary strategy of a tropical marine sponge
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Research conducted at the University of Hawaiʻi (UH) at Mānoa School of Ocean and Earth Science and Technology (SOEST) on a marine sponge in Kāneʻohe Bay, O?ahu revealed a unique feeding strategy, wherein the sponge animal acquires important components of its diet from symbiotic bacteria living within the sponge.
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Coral reefs are one of Hawaiʻi's most important natural resources and support fisheries and the state's economy. Marine sponges are important components of coral reef ecosystems, but in Hawaiʻi, the Indo-Australian sponge Mycale grandis is an invasive alien species that was only first documented in the islands in the late 1990s. M. grandis is now found in and near major harbors of the Main Hawaiian Islands as well as within Kāneʻohe Bay.Alien and invasive species are one of the threats to endemic and native species, which are vulnerable due to their evolution in the remote archipelago. M. grandis competes with coral for space on the reef, but unlike coral, which build hard rocky substrate with their skeletons, M. grandis is a soft, non-reef building animal and does not provide the same habitat for other reef organisms.In a study led by Dr. Joy Leilei Shih for her doctoral research at UH Mānoa, the diet of M. grandis sponges collected from Kāneʻohe Bay was elucidated by using a new application of a technique that relies on naturally occurring stable isotopes to understand the origin of specific compounds in the tissues of plants and animals. In this case, the team tested where amino acids, the building blocks of proteins in tissues, in the sponge came from. Did they originate from food caught and filtered from seawater or were they supplied to the sponge from the microbes living within the sponge itself?When one organism consumes another, elemental properties in the prey are conserved and leave behind a unique chemical pattern with the predator. By assessing the chemical difference between predator and prey tissues, Shih and colleagues found the diet of sponges did not originate from photosynthesizing microbes (such as seen in corals) and M. grandis feeding did not follow general patterns of other multicellular animals. Instead, the isotopic patterns of the sponge and its symbiotic microbes were not different from one another, indicating the sponge obtains nutrition through the uptake of amino acids originating from their symbiotic microbes."While we knew that the symbionts of sponges play an important role in their diet, the mechanism by which it occurred was unknown," said Shih. "The only way to produce the observed amino acid isotopic pattern, or fingerprint, if you will, is through the direct transfer of amino acids from their symbiotic bacteria.""The patterns we detected in M. grandis and its symbionts are very interesting, as they suggest sponges may be actively capturing materials in seawater to support the needs of their microbial community, which in turn supply the sponge with essential tissue building blocks," said Dr. Chris Wall, a postdoctoral researcher at UH Mānoa and a co-author on the study."The symbiosis we see between the sponge and its microbial community is remarkable," said Shih. "We know that sponges rely on their symbionts for a variety of purposes including chemical defense, metabolite removal, and now we have insight into this well-tuned and efficient feeding strategy and the major role these microbial symbionts play in sponge nutrition. The intimate relationship between sponges and their symbionts developed over their long evolutionary history. Sponges are the oldest multi-cellular animal on earth. That's why they are so well-adapted and resilient."Marine sponges in Hawaiʻi are not well studied. A study by the Smithsonian Institution-organized MarineGEO Hawaiʻi program in 2017 identified 150 previously unseen sponge species in Hawaiʻi, roughly one third of which are new species. Previously, only about 10 sponge species were known to exist in Kāneʻohe Bay. The researchers' new approach to investigating sponge feeding strategies can be applied to future research on other marine sponges in Hawai'i and elsewhere. Sponges play an important role in the nutrient dynamics of coral reefs, and in the future, sponges may rise to dominate coral reefs as corals decline from direct pressure from human activity and climate change. This work provides new insights into the biology of sponges and shows the importance of marine microbes to the diet of an invasive sponge.
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Extinction
| 2,019 |
August 13, 2019
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https://www.sciencedaily.com/releases/2019/08/190813170729.htm
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Non-native invasive insects, diseases decreasing carbon stored in US forests
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In addition to cleaning the air and water, forests hold a tremendous amount of sequestered carbon. When trees die and then decay on the forest floor, that carbon is released into the atmosphere, a phenomenon that is one of the drivers of climate change. A first-of-its-kind study by a team that included the United States Department of Agriculture's Forest Service and Purdue University scientists finds that non-native invasive insects and diseases are reducing the amount of carbon stored in trees across the United States.
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The study by Forest Service scientists Randall Morin, Chris Oswalt and Andrew Liebhold with lead author Songlin Fei of Purdue University used data from 92,978 field plots sampled by the Forest Service's Forest Inventory and Analysis (FIA) program in is the first attempt to comprehensively quantify the cumulative losses of trees following invasion by all species of non-native insects and diseases at a national scale.In North America, forests account for an estimated 76 percent of carbon sequestration, or removal from the atmosphere and storage globally. "The key impact of the tree-killing alien insects and diseases is that they are greatly increasing the rate at which trees die on average," Liebhold said. "This transfers carbon stored in live trees to dead material and much of this carbon will likely return to the atmosphere."Scientists emphasized that the study does not suggest that insect-killed trees become instant sources of carbon emissions. "Carbon transfers from living trees and plants to dead organic matter, and the release of carbon occurs gradually with decomposition of organic matter," Fei said. "However, the total amount of carbon in these dead materials are substantial, which is comparable to carbon emissions from 4.4 million cars or nearly one-fifth of all wildfires in the United States annually."More than 430 non-native insects and diseases have found their way to U.S. forests. Most of these species have little known effects on forests, however 83 have caused noticeable damage. In their study, Fei and Forest Service scientists examined the impacts of these 83 known damaging non-native forest insect and disease species and estimated the rate at which live tree biomass has been killed by the 15 species that have had the greatest impacts on forests. Insects such as the emerald ash borer, gypsy moth, and hemlock woolly adelgid and diseases including Dutch elm disease, beech bark disease and laurel wilt disease are among the 15 most damaging non-native species.As these insects and diseases continue to spread and tree mortality increases, the toll on forested landscapes and associated carbon storage will continue; the study suggests that 41 percent of the total live forest biomass remaining in the conterminous United States is threatened.For more than 80 years, FIA has been collecting data that informs forest management. Historically the large dataset has been used by states and private groups to monitor forest area, health, and conditions. Recent collaborations have demonstrated novel, interdisciplinary applications. "This study demonstrates the power of the FIA data to quantify the impact that non-native forest pests are having in the United States," Morin said.
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Extinction
| 2,019 |
August 13, 2019
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https://www.sciencedaily.com/releases/2019/08/190813105439.htm
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Poo's clues: Moose droppings indicate Isle Royale ecosystem health
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Given the choice between ice cream and vegetables, for many people it'll be the ice cream. But sometimes it depends on the situation. If you'd eaten ice cream every day for a week, you might prefer the salad. Human preferences for different foods often depend on what's common fare and what's rare.
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For non-human animals, like moose, the situation is equally complicated. An adult moose must eat approximately 40 pounds of vegetation per day just to keep itself going. Yet despite their need to consume large volumes of food every day, moose do not eat everything they come across. Instead, moose are considerably more selective than is obvious when deciding which plant species to eat.Sarah Hoy, assistant research professor, and John Vucetich, distinguished professor, in the School of Forest Resources and Environmental Science at Michigan Technological University, in collaboration with scientists from the United States Geological Survey (USGS) and the University of Wyoming, have developed a method to analyze why moose choose to eat what they do, how their choices change in the presence of predation and how moose diets actually affect the stability of entire ecosystems.The results appear in "Negative frequency-dependent foraging behaviour in a generalist herbivore ("The research shows how what you would think is a simple decision -- what to eat -- is a complex process that depends on many environmental factors, such as how common food types are, how likely a moose is to be killed by a predator and how difficult deep snow makes it to move around and find food," Hoy said. "The moose eat upwards of 40 pounds each day. You'd think if you had such dietary requirements you'd stuff your face with anything you can find, but that doesn't appear to be the case.""Something one might consider small, even trivial -- what a moose chooses to eat -- appears to have a stabilizing effect on the whole food web." -- Sarah Hoy, assistant research professorThe advantage to moose of taking the time to seek out and eat plant species that are relatively rare is a well-balanced diet, which requires nutrients that might be found only in those rarer plants. Many plants also contain chemicals that are toxic to moose in large quantities, which means that moose can ingest them only in limited amounts. However, a moose whose palate is too discerning pays a price; a cost of focusing too much on the rare plants is the time spent on the search. Additionally, a moose in search of a delicacy might be a more likely target for a wolf."Moose have a choice: eat the rare stuff at risk of not eating enough food overall, or eat what is most common in the forest at risk of missing out on a well-balanced diet," Hoy said. "We hadn't really known how moose manage that choice until now."By analyzing a decade's worth of moose droppings under a polarized light microscope -- a technique known as microhistology, which is further explored on Michigan Tech's Unscripted science and research blog -- to determine what exactly moose are eating on Isle Royale, the researchers concluded that moose preferred to eat what was relatively rare in their home range. If balsam fir is rare, they prefer it; if balsam fir is common, they show less preference -- even passing it up in many cases to find a less common plant. However, moose appeared to become less fussy eaters in years when the risk of being killed by wolves was high and in years when deep snow likely made it more difficult for moose to move around and find food.By combining the evidence of years of meticulous fieldwork with a mathematical model representing the Isle Royale system, Hoy and her fellow scientists were able to draw conclusions about why it's important that moose are choosy eaters in the context of the ecosystem.Enter Rongsong Liu, associate professor of mathematics at the University of Wyoming. Liu built a mathematical food chain model that she said, "demonstrates that the selective foraging strategies of moose can have an important stabilizing effect on community dynamics and provide a useful framework for assessing the influence of the other aspects of foraging behavior on community stability."The model further illuminates the strength of the connections across three trophic levels of the Isle Royale landscape: vegetation, herbivore, carnivore."The mathematical model is a way to test how important the patterns in moose behavior we observed are for the community as a whole," Hoy said. "Moose may change their diet in response to a harsh winter or a high risk of being killed by wolves, but how important is that to the ecosystem?"Don DeAngelis, a research ecologist for the USGS, has worked with Liu to develop and analyze models of herbivores of the boreal forest, including moose. One factor influencing what a moose prefers to eat is the aforementioned toxins in certain plants and how those toxins can effectively skew moose diets toward better overall balance."The data implied the moose were deliberately limiting their intake of coniferous vegetation, and also that this effect was related to the level of other environmental conditions, probably the level of predation by wolves," DeAngelis said. "My role was to work with Liu to translate the way that we think wolves, moose and forest vegetation all interact with each other into mathematical equations, and then use these equations to build a model that reflects the way that the Isle Royale ecosystem works."Ecological theory indicates that simple food chains, such as that of Isle Royale National Park, are prone to extinction. Where there is a single predator -- wolves -- and a single herbivore -- moose, which eats two basic kinds of plants: deciduous and conifer trees -- there can be erratic population fluxes. However, Hoy, Vucetich and colleagues discovered that the foraging behavior of the moose might be one factor that favors the persistence of wolves, moose and the different tree species in the food chain.This distinctive combination of theoretical models and field observations from the predator-prey study on Isle Royale provides ecologists with more insight about how and why populations tend to persist where basic theories of ecology otherwise suggest that they should not.
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Extinction
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August 13, 2019
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https://www.sciencedaily.com/releases/2019/08/190813102403.htm
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Coca and conflict: The factors fuelling Colombian deforestation
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Deforestation in Colombia has been linked to armed conflict and forests' proximity to coca crops, the plant from which cocaine is derived.
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A University of Queensland-led study found that conflict between illegal groups and the governmental military forces, proximity to coca plantations, mining concessions, oil wells and roads were all associated with increased deforestation.UQ PhD student Pablo Negret said the study identified how local drivers of deforestation in tropical countries affect deforestation risk."The relationship between conflict and deforestation is far from simple," he said."Many factors interact to increase or decrease deforestation risk, but stable governance can help forest retention."Mr Negret said establishing governmental control where Colombia's largest dissident group, the Revolutionary Armed Forces of Colombia (FARC), was present was essential to avoiding further deforestation."We need clear policy and action to stop the uncontrolled deforestation that has occurred since the official peace treaty between the Colombian Government and FARC was signed in 2016."Our research shows that conservation projects need to work in parallel with social projects and substituting illegal coca crops."One way to do this is to work with the communities in Indigenous reserves and Afro-Colombian collective lands to reach conservation objectives, while fostering economic activity."The researchers used forest cover information collected from satellites between 2000 and 2015, analysing the association of 17 variables with deforestation patterns in the country.Fellow study author Professor Martine Maron said by determining the drivers of deforestation the study could help prompt action to save at-risk forests."We must stop the full-scale destruction of the world's forests if we are to control the biodiversity and climate crisis," she said."And by teasing out the complex factors that threaten forests in a country like Colombia, we may be able to find effective solutions for addressing social and environmental ills across the globe."Peace and sustainability make good bedfellows."The study involved an international team from UQ, Wildlife Conservation Society, The Nature Conservancy, the Alexander von Humboldt Biological Resources Research Institute and the World Wide Fund for Nature.
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Extinction
| 2,019 |
August 12, 2019
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https://www.sciencedaily.com/releases/2019/08/190812144926.htm
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Study examines a million corals one by one in urgent call to save reefs
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When Joleah Lamb strapped on a scuba tank and plunged into the ocean over a decade ago, it was the first of many expeditions to examine the effects of climate change and other human-produced factors on coral.
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Now, 13 years after that foray, she has contributed one of the largest amounts of data to a landmark study on how to save coral reefs in the Indian and Pacific Oceans. Lamb, an assistant professor of ecology & evolutionary biology at the University of California, Irvine School of Biological Sciences, is among more than 80 marine researchers worldwide who produced the report. It has been published in The research encompassed over 2,500 reefs across 44 countries. Lamb provided its fourth-largest dataset, containing details on more than a million individual corals. Gathering the information required painstaking visual inspection, with Lamb and colleagues swimming underwater for as much as six hours each day. Armed with special measuring tapes, waterproof paper and pencils, they recorded information on each coral, meticulously identifying the size and health of more than 300 unique species.Key to this study were observations of bleaching, a visible indication water is too warm. When temperatures rise, corals expel algae they normally depend on for energy. The depletion robs the corals of their color and turns them white. It also eventually starves them."There are efforts to use drones or satellites to collect this information, but you cannot get the high resolution needed to assess the vital complex architecture of reefs unless you are in the water," said Lamb.The scientists involved in the report say it's not too late to save reefs if three strategies are immediately enacted in the Indo-Pacific. One is protecting from human impact those that are functioning, representing 17 percent of the reefs studied. Another is helping the 54 percent that are damaged but have the potential to recover. For 28 percent, it may be too late for rescue, which suggests some coastal societies will need to transition away from depending on them.Lamb says Americans should be concerned about the research results. "There are a lot of reefs in our territories, such as Hawaii, American Samoa and Guam," she said. "They all face severe impacts from the loss of coral reefs, including on coastal protection, food and income from tourism. And even if you don't live close to a reef, carbon emissions contribute to climate change that harms corals worldwide."Besides university scientists, researchers with the Wildlife Conservation Society, other non-profit organizations and governmental agencies participated in the study. The massive project demonstrates the need for collaboration in combatting environmental threats, she said."As scientists, we can tend to work in small domains and become microscopic in what we examine," she added. "We can't be that way anymore. We must work together on large global solutions that protect our world."
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Extinction
| 2,019 |
August 8, 2019
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https://www.sciencedaily.com/releases/2019/08/190808111429.htm
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Marine heatwaves a bigger threat to coral reefs than previously thought, scientists find
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Marine heatwaves are a much bigger threat to coral reefs than previously thought, research revealing a previously unrecognized impact of climate change on coral reefs has shown.
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In the study, scientists show for the first time what really happens to corals during marine heatwaves, and they reveal that it's not just coral animals that are affected -- their skeletons start to decay within weeks, too. This means that the 3D coral framework which provides home to many other animals on the reef is also at risk.The study by a team of researchers from UNSW Sydney, The University of Newcastle, The University of Technology Sydney, James Cook University and The National Oceanographic and Atmospheric Administration (NOAA), USA was published today in journal In 2016 the team's research showed that just a 0.5OC increase in ocean temperature changes the extent of mortality that happens in coral during bleaching.In this study, the team now find that severe marine heatwaves not only trigger bleaching events as we have known them -- a breakdown of symbiosis -- but in fact can lead to heat-induced mortality of the coral animal itself. They suggest that severe heatwave-induced mortality events should therefore be considered a distinct biological phenomenon, with more direct damage different from coral bleaching."Until now, we have described coral bleaching as an event where the symbiotic relationship between coral and its microbes breaks down and corals lose their main source of nutrition, and the coral can die if the symbiosis is not restored," author Associate Professor Tracy Ainsworth from UNSW says."But what we are now seeing is that severe marine heatwave events can have a far more severe impact than coral bleaching: the water temperatures are so warm that the coral animal doesn't bleach -- in terms of a loss of its symbiosis -- the animal dies and its underlying skeleton is all that remains.""We find that the skeleton is immediately overgrown by rapid growth of algae and bacteria," says Associate Professor Bill Leggat of the University of Newcastle, a co-author on the paper."We were able to study the consequences of this process of rapid colonisation using CT scanning of the coral skeleton -- as would be used in medical imaging. We show that this process is devastating not just for the animal tissue, but also for the skeleton that is left behind, which is rapidly eroded and weakened."University of Technology Sydney scientists A/Professor David Suggett and Dr Emma Camp explain how they were also able to use novel bio-optical techniques that allow them to visualise and study the rapid transition in the coral microbiome for the first time."With this technique, we can see Dr Scott Heron from James Cook University says this rapid dissolving of coral skeletons following severe heatwaves hasn't been known to date."Climate scientists talk about 'unknown unknowns' -- impacts that we haven't anticipated from existing knowledge and experience. This discovery fits into this category. As we begin now to understand this impact, the question is how many more of these 'unknown unknowns' might there still be that could bring faster and greater damage to coral reefs from climate change," he says.Dr Mark Eakin, Coordinator of NOAA's Coral Reef Watch, says such events are predictable."We already use climate models and satellite data to predict and detect conditions that cause coral bleaching. By focusing on especially severe marine heatwaves, we should be able to predict this direct coral death, too."A/Prof Ainsworth says that the team hopes that this research will motivate the public to tell decision makers how important coral reefs are to them, and voice the immediate need to preserve coral reefs now."Across the globe coral reefs are still a source of inspiration and awe of the natural world, as well as being critically important to the communities that rely upon them. Given that the degradation of coral reefs will result in the collapse of ecosystem services that sustain over half a billion people, we urgently need actions both globally and locally that protect and conserve these truly wonderful places."
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Extinction
| 2,019 |
August 7, 2019
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https://www.sciencedaily.com/releases/2019/08/190807142233.htm
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Permian lizard-like animal suffered from a bone condition similar to Paget's disease
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A lizard-like animal that lived 289 million years ago suffered from a bone condition similar to Paget's disease, according to a study published August 7, 2019 in the open-access journal
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The animal in question belonged to an extinct group of lizard-like creatures called varanopids, relatives of the earliest ancestors of mammals or reptiles. The authors identified the disease in an isolated pair of tail vertebrae discovered in an Early Permian cave at Richards Spur, Oklahoma. Micro-CT scanning allowed examination of both the external and internal structure of the elements, revealing that in some places the bone had been thinned by abnormally high levels of reabsorption, while in other areas excessive bone growth had resulted in abnormal bone thickening and the ultimate fusion of the two vertebrae.According to the researchers, this condition is most similar to Paget's disease, a bone metabolic disorder marked by a breakdown in communication between bone building cells and bone destroying cells. Paget's disease is commonly seen today in the hips and vertebrae of humans and has been diagnosed in other living mammals and reptiles as well as one Early Jurassic dinosaur fossil. The disease has been linked to both genetic and viral factors, though its precise cause remains controversial.With only two vertebrae preserved, it is impossible to say how widespread the disease was in this animal's body. If it was restricted to the tail, the animal may only have suffered minor pain and stiffness. This discovery marks the oldest known occurrence of a Paget-like disease and suggests that susceptibility to such disorders was already present in our early Permian cousins.Haridy adds: "Paleopathology is the study of ancient diseases, here we scanned a pair of fused tail bones from a permian (280 million years ago) Varanopid (a superficially-lizard like animal), what we found was evidence of a bone disease similar to modern day Paget's disease. This enigmatic disease is still not well understood in humans, however finding something similar in an ancient animal likely links it to something deep in our bone biology. This study is a great example of how when palaeontologists have well preserved fossils we can tell a lot more than just what animals were present, we can explore their biology, physiology and even what diseases ailed them!"
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Extinction
| 2,019 |
August 7, 2019
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https://www.sciencedaily.com/releases/2019/08/190807092340.htm
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The surprising merit of giant clam feces
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Coral reefs are a hotspot of biodiversity, hosting numerous species of animals and fish that help one another maintain a harmonious environment. One of these species is the giant clam. They are the biggest shellfish in the world, with 13 species found so far. One of the most famous species, Tridacna gigas, can live more than 100 years and grow to more than a meter wide. Their size and beautiful shells have led to their popularity as ornaments and as a delicacy, but this has resulted in their endangerment.
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Impressive size and beauty and are not the only notable facts about giant clams, they also play host to symbiotic algae: Zooxanthellae. These algae have a very important role in the maintenance of the coral reef, they provide food for the coral and clam through products of photosynthesis. About 80% of coral reef nutrition and 65-70% of giant clam nutrition comes from the symbiotic relationship with zooxanthellae. However, these algae are not able to survive without a host and don't appear to be present in large amounts in the water or sediment surrounding the coral reef."In the coral reef the water is very clear, this means there is no food floating around. The zooxanthellae feed the coral reefs." explains Professor Kazuhiko Koike, Graduate School of Integrated Sciences for Life at Hiroshima University and leader of this study.Although these algae are vital to the coral reef, they must be obtained through the environment somehow because most of corals and giant clams do not obtain zooxanthellae from their parents."The only big mystery of coral reefs is where do the zooxanthellae come from?" says Koike.To try and solve this mystery researchers from Hiroshima University, in a collaboration with The Fisheries Research and Education Agency Okinawa, Okinawa Prefectural Fisheries Research and Extension Center, and the National University of Singapore tried to find the mode of transmission of algae from clam to clam."One of my former students, Shato Ikeda, found that if a coral reef is very healthy the giant clams are always there." describes Koike. "There are many scientists with big research budgets already looking at coral. So, we changed our [research] model to the giant clam."While researching the giant clams, a member of the research team (Shinya Morishima) noticed that the fecal pellets were full of zooxanthellae. When the algae were studied under a fluorescent microscope, the scientists observed that they were alive and active, with intact chloroplasts (parts of the cell that perform photosynthesis). The team then grew juvenile clams in the laboratory and fed them fecal pellets from adult giant clams originally harvested in Okinawa. 34% of the larvae took up the zooxanthellae from the fecal pellets and 5% of larvae established symbiosis with feces-borne zooxanthellae reached, a rate higher than current experimental methods.The types of zooxanthellae contained in the larvae were similar to those in the fecal pellets and were photosynthetically active.Although this is a preliminary study, Koike believes that this could help solve a big mystery to coral reef maintenance."This is the first step to expand our research to coral reefs." hopes Koike.Under elevating temperature, due to global warming, more heat-resistant zooxanthella grow in the clams and so more are expelled in their fecal pellets. In the future Koike thinks that giant clams could provide these heat-resistant zooxanthellae to coral reefs to mitigate against coral bleaching caused by climate change.
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Extinction
| 2,019 |
August 6, 2019
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https://www.sciencedaily.com/releases/2019/08/190806101528.htm
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Strange coral spawning improving Great Barrier Reef's resilience
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A phenomenon that makes coral spawn more than once a year is improving the resilience of the Great Barrier Reef.
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The discovery was made by University of Queensland and CSIRO researchers investigating whether corals that split their spawning over multiple months are more successful at spreading their offspring across different reefs.Dr Karlo Hock, from UQ's School of Biological Sciences, said coral mass spawning events are one of the most spectacular events in the oceans."They're incredibly beautiful," Dr Hock said."On Australia's Great Barrier Reef, all coral colonies typically spawn only once per year, over several nights after the full moon, as the water warms up in late spring."Study co-author Dr Christopher Doropoulos from the CSIRO Oceans & Atmosphere said sometimes however, coral split their spawning over two successive months."This helps them synchronise their reproduction to the best environmental conditions and moon phases," he said."While reproductive success during split spawning may be lower than usual because it can lead to reduced fertilisation, we found that the release of eggs in two separate smaller events gives the corals a second and improved chance of finding a new home reef."The research team brought together multi-disciplinary skills in modelling, coral biology, ecology, and oceanography, simulating the dispersal of coral larvae during these split spawning events, among the more than 3800 reefs that make up the Great Barrier Reef.They looked at whether the split spawning events more reliably supply larvae to the reefs, as well as whether the ability to exchange larvae among the reefs is enhanced by them.UQ's Professor Peter J. Mumby said split spawning events can increase the reliability of larval supply as the reefs tend to be better connected and have more numerous, as well as more frequent, larval exchanges."This means that split spawning can increase the recovery potential for reefs in the region."A more reliable supply of coral larvae could particularly benefit reefs that have recently suffered disturbances, when coral populations need new coral recruits the most."This will become more important as coral reefs face increasingly unpredictable environmental conditions and disturbances."Dr Hock said the research also revealed that the natural processes of recovery can sometimes be more resilient than originally thought."However, even with such mechanisms in place, coral populations can only withstand so much pressure," he said."It all ends up being the matter of scale: any potential benefits from split spawning might be irrelevant if we don't have enough coral on these reefs to reproduce successfully."Mitigating well-established local and global threats to coral reefs -- like river runoffs and carbon dioxide emissions -- is essential for their continued survival."The study between UQ, CSIRO and ARC Centre of Excellence for Coral Reef Studies was published in
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Extinction
| 2,019 |
August 6, 2019
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https://www.sciencedaily.com/releases/2019/08/190806101522.htm
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New species of dinosaur discovered after lying misidentified in fossil vaults for 30 years
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A PhD student of the University of the Witwatersrand, South Africa, has discovered a new dinosaur species in the University's vaults, after it has been laying misidentified in a collection for 30 years.
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The team of scientists, led by PhD Student Kimberley Chapelle, recognised that the dinosaur was not only a new species of sauropodomorph, but an entirely new genus. The specimen has now been named Ngwevu intloko which means "grey skull" in the Xhosa language, chosen to honour South Africa's heritage. She was joined in the research by her PhD supervisors: Prof Jonah Choiniere (Wits), Dr Jennifer Botha (National Museum Bloemfontein), and Professor Paul Barrett (Natural History Museum, London). Together, Kimberley and these world-leading researchers have been improving knowledge of South African palaeontology for the last six years. The dinosaur has been described in the academic journal, Professor Paul Barrett, Chapelle's PhS supervisor and researcher at the Natural History Museum in the UK explains, "This is a new dinosaur that has been hiding in plain sight." "The specimen has been in the collections in Johannesburg for about 30 years, and lots of other scientists have already looked at it. But they all thought that it was simply an odd example of Massospondylus."Massospondylus was one of the first dinosaurs to reign at the start of the Jurassic period. Regularly found throughout southern Africa, these animals belonged to a group called the sauropodomorphs and eventually gave rise to the sauropods, a group containing the Natural History Museum's iconic dinosaur cast Dippy. Researchers are now starting to look closer at many of the supposed Massospondylus specimens, believing there to be much more variation than first thought.Kimberley Chapelle explains why the team were able to confirm that this specimen was a new species, "In order to be certain that a fossil belongs to a new species, it is crucial to rule out the possibility that it is a younger or older version of an already existing species. This is a difficult task to accomplish with fossils because it is rare to have a complete age series of fossils from a single species. Luckily, the most common South African dinosaur Massospondylus has specimens ranging from embryo to adult. Based on this, we were able to rule out age as a possible explanation for the differences we observed in the specimen now named Ngwevu intloko."The new dinosaur has been described from a single fairly complete specimen with a remarkably well-preserved skull. The new dinosaur was bipedal with a fairly chunky body, a long slender neck and a small, boxy head. It would have measured three metres from the tip of its snout to the end of its tail and was likely an omnivore, feeding on both plants and small animals.The findings will help scientists better understand the transition between the Triassic and Jurassic period, around 200 million years ago. Known as a time of mass extinction it now seems that more complex ecosystems were flourishing in the earliest Jurassic than previously thought."This new species is interesting," says Prof Barrett, "because we thought previously that there was really only one type of sauropodomorph living in South Africa at this time. We now know there were actually six or seven of these dinosaurs in this area, as well as variety of other dinosaurs from less common groups. It means that their ecology was much more complex than we used to think. Some of these other sauropodomorphs were like Massospondylus, but a few were close to the origins of true sauropods, if not true sauropods themselves."This work shows the value of revisiting specimens in museum collections, as many news species are probably sitting unnoticed in cabinets around the world.
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Extinction
| 2,019 |
August 5, 2019
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https://www.sciencedaily.com/releases/2019/08/190805112148.htm
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Long-lasting effects of ironwork on mammal distributions over the last millennium
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Awareness is growing among scientists about the significance of pre-modern anthropogenic impacts prior to the Industrial Revolution on present-day patterns of biodiversity. In particular, pre-modern energy-intensive industries, such as ironwork, of the sort depicted in the 1997 anime film Princess Mononoke directed by Hayao Miyazaki, were major drivers of ecosystem alteration and have had long-lasting impacts on the distributions of many species. However, the phenomenon remains insufficiently studied and the empirical evidence is quite limited.
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Millennial-scale effects of past energy-intensive anthropogenic activities are the subject of a new study led by two Japanese researchers from the National Institute for Environmental Studies and Obihiro University of Agriculture and Veterinary Medicine, published in The researchers used a statistical framework to estimate the impact of pre-modern ironwork during four historical periods in the last millennium on the current distributions of 29 mammalian genera native to Japan, taking into account other potential factors such as paleoclimate and modern-day land use. Past ironwork impacts were quantified using site records from a national archaeological database.The c urrent distributions of 21 of 29 mammalian genera were significantly affected by the impacts of past ironwork activities. In particular, the impacts of ironwork in the Kofun period (about 1700-1300 years ago), when iron production originally began in Japan, were significant for 13 genera. Medium-to-large mammals, such as the fox and wild boar, showed positive responses to the impacts of ironwork, but small mammals, such as the flying squirrel and dormouse, were negatively impacted in many different historical periods. The difference in response between small and medium-to-large mammals could be explained by traits related to body size, such as dispersal ability and habitat generalism, which are important for survival in a disturbed, heterogeneous landscape."Ironwork brought long-term environmental change in multiple ways," says lead author Keita Fukasawa of the National Institute for Environmental Studies. "It required large quantities of charcoal, and the mountains around ironworking sites were often stripped bare due to intensive logging. Moreover, mining of iron sand resulted in soil erosion, which sometimes led to irreversible habitat degradation for small mammals dwelling in old-growth forests. However, such habitat alterations also contributed to the development of the traditional rural landscape in Japan, called satoyama, which consists of patches of various types of habitats such as grassland and secondary forest, which are suitable for medium-to-large mammals.""Today in Japan , iron production relies on imported iron ore and fossil fuels, so the exploitation of domestic resources for iron production has ended. On a global scale, however, over-exploitation of firewood and mining remain drivers of biodiversity loss. Studies examining the long-lasting effects of pre-industrial Anthropogenic activities on biodiversity will offer insights into the historical background to macro-ecological patterns and provide practical knowledge for the development of sustainable societies in the Anthropocene that mitigate impacts on ecosystems. For example, if we can identify species that may be negatively impacted over the long term by the exploitation of a specific resource, it will help us to establish appropriate zoning for conservation and resource use."
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Extinction
| 2,019 |
August 5, 2019
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https://www.sciencedaily.com/releases/2019/08/190805111913.htm
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Intense look at La Brea Tar Pits explains why we have coyotes, not saber-toothed cats
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The most detailed study to date of ancient predators trapped in the La Brea Tar Pits is helping Americans understand why today we're dealing with coyotes dumping over garbage cans and not saber-toothed cats ripping our arms off.
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Larisa DeSantis, a Vanderbilt University paleontologist, grew up visiting the one-of-a-kind fossil site in Los Angeles, which contains fossils of predators that tried to eat horses, bison and camels stuck in the tar over the past 50,000 years and themselves became trapped, offering the best opportunity to understand Ice Age animals facing climate change. The Pleistocene Epoch spanned 2.6 million years ago to about 10,000 years ago, encompassing multiple glacial and interglacial periods and the arrival of humans, one or both of which forced predators to adapt their diets or die.DeSantis spent the last decade visiting La Brea, studying the teeth of extinct species such as American lions, saber-toothed cats and dire wolves; and teeth from ancient animals whose offspring are still alive today, such as gray wolves, cougars and coyotes. Her work revealed that competition for prey among carnivores wasn't a likely cause of the Pleistocene megafaunal extinction as formerly believed, because, like dogs and cats of today, one preferred running after herbivores in the open fields, while the other preferred stalking them in forested areas."Isotopes from the bones previously suggested that the diets of saber-toothed cats and dire wolves overlapped completely, but the isotopes from their teeth give a very different picture," said DeSantis, an associate professor of biological sciences at Vanderbilt. "The cats, including saber-toothed cats, American lions and cougars, hunted prey that preferred forests, while it was the dire wolves that seemed to specialize on open-country feeders like bison and horses. While there may have been some overlap in what the dominant predators fed on, cats and dogs largely hunted differently from one another."To study these ancient predators, she employs dentistry -- taking molds of the teeth and shaving off tiny bits of enamel for chemical analysis. Information about everything the animal ate lies within the isotopes, she said. Further, the microscopic wear patterns on teeth can clarify who was eating flesh or scavenging on bones.It's likely that those giant predators went extinct due to climate change, the arrival of humans to their environment or a combination of the two, she said, and her team is working to clarify the cause of the extinction with multiple colleagues across six institutions as part of a separate on-going study.What they know is predators alive today in the Americas were better able to adapt their diets. Instead of only feeding on large prey, they could effectively hunt small mammals, scavenge what they could from carcasses or do both."The other exciting thing about this research is we can actually look at the consequences of this extinction," DeSantis said. "The animals around today that we think of as apex predators in North America -- cougars and wolves -- were measly during the Pleistocene. So when the big predators went extinct, as did the large prey, these smaller animals were able to take advantage of that extinction and become dominant apex-predators."An even more detailed picture of ancient life at La Brea is contained in the paper "Causes and consequences of Pleistocene megafaunal extinctions as revealed from Rancho La Brea mammals," published today in the journal The work was supported by National Science Foundation grant EAR1053839.
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Extinction
| 2,019 |
August 2, 2019
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https://www.sciencedaily.com/releases/2019/08/190802092429.htm
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Eleven new species of rain frogs discovered in the tropical Andes
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Eleven new to science species of rain frogs are described by two scientists from the Museum of Zoology of the Pontifical Catholic University of Ecuador in the open-access journal
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On the one hand, the publication is remarkable because of the large number of new species of frogs. Regarding vertebrate animals, most studies only list between one and five new to science species, because of the difficulty of their collection and the copious amount of work involved in the description of each. To put it into perspective, the last time a single article dealt with a similar number of newly discovered frogs from the western hemisphere was in 2007, when Spanish scientist Ignacio de la Riva described twelve species from Bolivia.On the other hand, the new paper by Nadia Paez and Dr Santiago Ron is astounding due to the fact that it comes as part of the undergraduate thesis of Nadia Paez, a former Biology student at the Pontifical Catholic University, where she was supervised by Professor Santiago Ron. Normally, such a publication would be the result of the efforts of a large team of senior scientists. Currently, Nadia Paez is a PhD student in the Department of Zoology at the University of British Columbia in Canada.Unfortunately, amongst the findings of concern is that most of the newly described frog species are listed as either Data Deficient or Threatened with extinction, according to the criteria of the International Union for Conservation of Nature (IUCN). All of the studied amphibians appear to have very restricted geographic ranges, spanning less than 2,500 km2. To make matters worse, their habitats are being destroyed by human activities, especially cattle raising, agriculture, and mining.Amongst the newly described species, there is the peculiar Multicolored Rain Frog, where the name refers to its outstanding color variation. Individuals vary from bright yellow to dark brown. Initially, the studied specimens were assumed to belong to at least two separate species. However, genetic data demonstrated that they represented a single, even if highly variable, species.The rest of the previously unknown frogs were either named after scientists, who have made significant contributions in their fields, or given the names of the places they were discovered, in order to highlight places of conservation priority.
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Extinction
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July 31, 2019
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https://www.sciencedaily.com/releases/2019/07/190731102157.htm
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Biodiversity highest on Indigenous-managed lands
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More than one million plant and animal species worldwide are facing extinction, according to a recent United Nations report. Now, a new UBC-led study suggests that Indigenous-managed lands may play a critical role in helping species survive.
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The researchers analyzed land and species data from Australia, Brazil and Canada -- three of the world's biggest countries -- and found that the total numbers of birds, mammals, amphibians and reptiles were the highest on lands managed or co-managed by Indigenous communities.Protected areas like parks and wildlife reserves had the second highest levels of biodiversity, followed by randomly selected areas that were not protected.The study, which focused on 15,621 geographical areas in Canada, Brazil and Australia, also found that the size of an area and its geographical location did not affect species diversity."This suggests that it's the land-management practices of many Indigenous communities that are keeping species numbers high," said lead author Richard Schuster, the Liber Ero Postdoctoral Fellow at Carleton University, who undertook the research while at UBC. "Going forward, collaborating with Indigenous land stewards will likely be essential in ensuring that species survive and thrive."The study is the first to compare biodiversity and land management on such a broad geographic scale, the researchers say."We looked at three countries with very different climates and species, to see if the pattern held true across these different regions -- and it did," said co-author Ryan Germain, a postdoctoral fellow at Cornell University. "From frogs and songbirds right up to large mammals like grizzly bears, jaguars and kangaroos, biodiversity was richest in Indigenous-managed lands."Traditional conservation programs relied on designating certain areas as parks and reserves, and these results highlight the importance of expanding conservation beyond its typical boundaries, says the study's senior author, UBC forestry professor Peter Arcese."Protected areas are a cornerstone of biodiversity conservation globally, but current levels of protection will be insufficient to halt the planetary extinction crisis," said Arcese, the Forest Renewal B.C. Chair in Conservation Biology at UBC. "We must manage a larger fraction of world's area in ways that protect species and leads to positive outcomes for people and the species they've relied on for millennia."The researchers noted that in the past, when protected areas were established, Indigenous peoples were sometimes excluded from using land they had previously relied on for food and materials. This was harmful to many Indigenous communities and did not necessarily achieve the original goals of conservation."Indigenous-managed lands represent an important repository of biodiversity in three of the largest countries on Earth, and Indigenous peoples currently manage or have tenure to roughly one-quarter of the planet's land area," said co-author Nick Reo, an associate professor of environmental studies and Native American studies at Dartmouth College and a citizen of the Sault Ste. Marie, Ontario tribe of Chippewa Indians."In light of this, collaborating with Indigenous governments, communities and organizations can help to conserve biodiversity as well as support Indigenous rights to land, sustainable resource use and well-being."
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Extinction
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