patrickbdevaney/mia9 · Datasets at Hugging Face

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locations, are nearly all Miami Limestone, a formation produced in the most recent interglacial
period of the Pleistocene Epoch when sea level was about 25 feet above today’s level. The
interglacial period gradually ended about 100,000 years before present. The parent material
deposited during the interglacial time was grains of calcium carbonate, formed by two shallowmarine processes. Along the eastern edge of the county’s mainland where accumulations were
thicker, the material consisted of small (but visible) egg-shaped grains of calcium carbonate
called “ooids.” These oolitic deposits thinned westward, away from the deeper waters of the
Atlantic, where they intergraded with fine-grained (microscopic) calcium carbonate particles
deposited from marine algae and the shells of tiny animals called bryozoans in a calmer shallow
marine interglacial environment away from more turbulent coastal waters. (Lodge 2005)
The most recent glacial period (with the glacial maximum occurring approximately 20,000 years
ago), caused much lower sea levels that exposed the sediments. The oolites were initially sand-
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 4
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 5
like and subject to wind redistribution and dune formation. Percolation of rainwater gradually
solidified the grains by recrystallization into the soft rock we now recognize as Miami
Limestone. (Lodge 2005)
2.2.2 Soils
The presence of a limestone substrate is a major defining character of the pine rockland
ecosystem which differentiates it from other types of pine-dominated ecosystems in Florida.
Soils in pine rocklands, when present, are usually nutrient-poor sand or loam in a matrix of
exposed oolitic limestone. Soil type varies with geographic location on the Miami Rock Ridge.
There are two main soil types in Miami-Dade’s pine rocklands outside of ENP. The USDA
(1996) has mapped these as Cardsound Rock Outcrop Complex and Opalocka Rock Outcrop
Complex. Each of these soils, when present, typically occurs as thin layers over the oolitic
limestone substrate, with much of the limestone breaking the surface of the soil deposit.
Opalocka Rock Outcrop Complex soil occurs north of the Goulds region. Robertson (1955)
referred to the region covered by this soil as the northern Biscayne pinelands. This soil is a
highly permeable quartz sand, which is usually white to brown in color (USDA 1996) and
slightly basic (Craighead 1971, USFWS 2000). The amount and depth of the quartz sands varies
with latitude. To the north, where the Miami Rock Ridge formerly merged with the sandy
Atlantic Coastal Ridge, sands were probably very extensive and deep (examples are now
destroyed). On some more northerly pine rockland fragments that currently exist, such as the
Ludlam Pineland and Rockdale Pineland EEL sites, the sands can be several feet thick and have
areas with little or no exposed limestone. In contrast, pine rocklands further south, such as those
at Larry and Penny Thompson Park, have thinner deposits of sand, which cover less area.
Cardsound Rock Outcrop Complex soil occurs south of the Goulds Region. Robertson (1955)
referred to the region covered by these soils as the southern Biscayne pinelands. This silty loam
soil is slightly basic (Craighead 1971, USFWS 2000) and dark reddish to brown in color
(typically called “Redland Soil”) (USDA 1996). It was from the color of this soil that the
“Redlands” area of southern Miami-Dade County derived its name. Cardsound soil is usually
only about four (4) inches thick and soil permeability is moderately slow (USDA 1996). Unlike
Opalocka soil, there is very little visible Cardsound soil in pine rocklands. The existing deposits
usually cover very small areas of a few square meters or less.
Pine rocklands are also known to contain features called solution holes. Solution holes are
“steep-sided pits of varying sizes formed by the dissolution of rock below the surface followed
by collapse at the top” (Myers and Ewel 1990). Deeper deposits of typically organic soil, noncharacteristic of the typical nutrient-poor sand or loam found in pine rocklands, may be found
within these holes.
2.2.3 Hydrology
Pre-drainage hydrology of pine rocklands varied greatly depending upon elevation. Some pine
rocklands, especially those further north in the county, probably never flooded, or flooded for
only very brief periods during major high water events. Other pine rocklands, such as those
along the west edge of the western Miami Rock Ridge or along the edges of the Transverse
Glades, probably flooded annually for short periods during the summer wet season. Pine
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 6
rocklands on Long Pine Key in ENP may flood for 20 to 60 days per year (Duever et al. 1979),
because these are at lower elevations than most pine rocklands outside of ENP.
2.3 Climate
Miami-Dade County has a subtropical climate that can be divided into two distinct seasons: a
mild dry season and a hot rainy season. The dry season is characterized by mild temperatures,
relatively low humidity, and very little rain. This season usually ranges from late October to mid
May. Occasional cold fronts arriving from Canada are the primary force of weather during the
dry season, disrupting a mild easterly flow off the Atlantic Ocean. High temperatures are
generally around 80 degrees and low temperatures can vary from the low 30s inland to the low
60s near the coast. Temperatures below 32 degrees occur some years. Humidity levels are
generally low with dew points below 60 degrees. The start of the wet season is different every
year, but it generally starts in mid May and lasts through October. The average temperatures
during the wet season range from the upper 80s along the coast to the mid 90s inland.
Precipitation amounts can be copious with monthly totals ranging from five (5) to nine (9) inches
and an annual average of 58 inches. The distinct mark of the wet season is consecutive days of
high humidity with dew points at or well above 60 degrees.
June 1 through November 30 marks the annual hurricane season. During this period Miami-Dade
County may be crossed by one or more tropical cyclones, including tropical depressions, tropical
storms, and hurricanes. The main impact of these storms is the strong winds. Hurricanes have
winds in excess of 74 miles per hour and can bring large amounts of rainfall in very short time
periods, causing regional flooding.
2.4 Vegetation Structure and Composition
Typically pine rocklands consist of three vegetation layers that vary in importance and diversity
according to specific local conditions. A canopy normally dominated by pine trees is followed by
a subcanopy composed of an array of temperate and tropical hardwoods and palms and a diverse
herb layer of a combination of forbs, grasses, ferns, and sedges. Details of the structure and
species richness of each of these layers is provided in the following paragraphs. Please refer to
Appendix B for pictures of historical vegetation structure and composition.
2.4.1 Canopy
The canopy of pine rocklands is dominated by a single species, South Florida slash pine, which
historically ranged in height from approximately 65 to 90 feet (Craighead 1971, Snyder et al.
1990). Diameters of pines historically ranged up to 24 to 30 inches (Craighead 1971, Robertson
1955). Platt et al. (2002) reported pre-Hurricane Andrew pine densities on fragmented pine
rockland sites of between 211 and 975 trees per acre. In the Long Pine Key area of ENP, preHurricane Andrew slash pine densities were recorded at 185 to 477 trees per acre (Snyder et al.
1990) and 294 to 863 trees per acre (Platt et al. 2002). Germination of South Florida slash pine
occurs from October to December. Seedling survival is higher where there is more soil moisture
(McMinn 1970). Seedlings will remain in a fire resistant “grass stage” for two (2) to five (5)
years. While in this grass stage the pines can re-sprout from the root collar after a fire (Ketcham
and Bethune 1963), allowing some to survive. Hofstetter (1973) reported that fires cause an 87%
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 7
mortality of seedlings less than five (5) feet tall and 50% mortality for those 6.6 to 19.8 feet tall.
Seedlings have improved survivability in areas with less duff accumulation (Klukas 1973).

locations, are nearly all Miami Limestone, a formation produced in the most recent interglacial

period of the Pleistocene Epoch when sea level was about 25 feet above today’s level. The

interglacial period gradually ended about 100,000 years before present. The parent material

deposited during the interglacial time was grains of calcium carbonate, formed by two shallowmarine processes. Along the eastern edge of the county’s mainland where accumulations were

thicker, the material consisted of small (but visible) egg-shaped grains of calcium carbonate

called “ooids.” These oolitic deposits thinned westward, away from the deeper waters of the

Atlantic, where they intergraded with fine-grained (microscopic) calcium carbonate particles

deposited from marine algae and the shells of tiny animals called bryozoans in a calmer shallow

marine interglacial environment away from more turbulent coastal waters. (Lodge 2005)

The most recent glacial period (with the glacial maximum occurring approximately 20,000 years

ago), caused much lower sea levels that exposed the sediments. The oolites were initially sand-

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 4

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 5

like and subject to wind redistribution and dune formation. Percolation of rainwater gradually

solidified the grains by recrystallization into the soft rock we now recognize as Miami

Limestone. (Lodge 2005)

2.2.2 Soils

The presence of a limestone substrate is a major defining character of the pine rockland

ecosystem which differentiates it from other types of pine-dominated ecosystems in Florida.

Soils in pine rocklands, when present, are usually nutrient-poor sand or loam in a matrix of

exposed oolitic limestone. Soil type varies with geographic location on the Miami Rock Ridge.

There are two main soil types in Miami-Dade’s pine rocklands outside of ENP. The USDA

(1996) has mapped these as Cardsound Rock Outcrop Complex and Opalocka Rock Outcrop

Complex. Each of these soils, when present, typically occurs as thin layers over the oolitic

limestone substrate, with much of the limestone breaking the surface of the soil deposit.

Opalocka Rock Outcrop Complex soil occurs north of the Goulds region. Robertson (1955)

referred to the region covered by this soil as the northern Biscayne pinelands. This soil is a

highly permeable quartz sand, which is usually white to brown in color (USDA 1996) and

slightly basic (Craighead 1971, USFWS 2000). The amount and depth of the quartz sands varies

with latitude. To the north, where the Miami Rock Ridge formerly merged with the sandy

Atlantic Coastal Ridge, sands were probably very extensive and deep (examples are now

destroyed). On some more northerly pine rockland fragments that currently exist, such as the

Ludlam Pineland and Rockdale Pineland EEL sites, the sands can be several feet thick and have

areas with little or no exposed limestone. In contrast, pine rocklands further south, such as those

at Larry and Penny Thompson Park, have thinner deposits of sand, which cover less area.

Cardsound Rock Outcrop Complex soil occurs south of the Goulds Region. Robertson (1955)

referred to the region covered by these soils as the southern Biscayne pinelands. This silty loam

soil is slightly basic (Craighead 1971, USFWS 2000) and dark reddish to brown in color

(typically called “Redland Soil”) (USDA 1996). It was from the color of this soil that the

“Redlands” area of southern Miami-Dade County derived its name. Cardsound soil is usually

only about four (4) inches thick and soil permeability is moderately slow (USDA 1996). Unlike

Opalocka soil, there is very little visible Cardsound soil in pine rocklands. The existing deposits

usually cover very small areas of a few square meters or less.

Pine rocklands are also known to contain features called solution holes. Solution holes are

“steep-sided pits of varying sizes formed by the dissolution of rock below the surface followed

by collapse at the top” (Myers and Ewel 1990). Deeper deposits of typically organic soil, noncharacteristic of the typical nutrient-poor sand or loam found in pine rocklands, may be found

within these holes.

2.2.3 Hydrology

Pre-drainage hydrology of pine rocklands varied greatly depending upon elevation. Some pine

rocklands, especially those further north in the county, probably never flooded, or flooded for

only very brief periods during major high water events. Other pine rocklands, such as those

along the west edge of the western Miami Rock Ridge or along the edges of the Transverse

Glades, probably flooded annually for short periods during the summer wet season. Pine

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 6

rocklands on Long Pine Key in ENP may flood for 20 to 60 days per year (Duever et al. 1979),

because these are at lower elevations than most pine rocklands outside of ENP.

2.3 Climate

Miami-Dade County has a subtropical climate that can be divided into two distinct seasons: a

mild dry season and a hot rainy season. The dry season is characterized by mild temperatures,

relatively low humidity, and very little rain. This season usually ranges from late October to mid

May. Occasional cold fronts arriving from Canada are the primary force of weather during the

dry season, disrupting a mild easterly flow off the Atlantic Ocean. High temperatures are

generally around 80 degrees and low temperatures can vary from the low 30s inland to the low

60s near the coast. Temperatures below 32 degrees occur some years. Humidity levels are

generally low with dew points below 60 degrees. The start of the wet season is different every

year, but it generally starts in mid May and lasts through October. The average temperatures

during the wet season range from the upper 80s along the coast to the mid 90s inland.

Precipitation amounts can be copious with monthly totals ranging from five (5) to nine (9) inches

and an annual average of 58 inches. The distinct mark of the wet season is consecutive days of

high humidity with dew points at or well above 60 degrees.

June 1 through November 30 marks the annual hurricane season. During this period Miami-Dade

County may be crossed by one or more tropical cyclones, including tropical depressions, tropical

storms, and hurricanes. The main impact of these storms is the strong winds. Hurricanes have

winds in excess of 74 miles per hour and can bring large amounts of rainfall in very short time

periods, causing regional flooding.

2.4 Vegetation Structure and Composition

Typically pine rocklands consist of three vegetation layers that vary in importance and diversity

according to specific local conditions. A canopy normally dominated by pine trees is followed by

a subcanopy composed of an array of temperate and tropical hardwoods and palms and a diverse

herb layer of a combination of forbs, grasses, ferns, and sedges. Details of the structure and

species richness of each of these layers is provided in the following paragraphs. Please refer to

Appendix B for pictures of historical vegetation structure and composition.

2.4.1 Canopy

The canopy of pine rocklands is dominated by a single species, South Florida slash pine, which

historically ranged in height from approximately 65 to 90 feet (Craighead 1971, Snyder et al.

1990). Diameters of pines historically ranged up to 24 to 30 inches (Craighead 1971, Robertson

1955). Platt et al. (2002) reported pre-Hurricane Andrew pine densities on fragmented pine

rockland sites of between 211 and 975 trees per acre. In the Long Pine Key area of ENP, preHurricane Andrew slash pine densities were recorded at 185 to 477 trees per acre (Snyder et al.

1990) and 294 to 863 trees per acre (Platt et al. 2002). Germination of South Florida slash pine

occurs from October to December. Seedling survival is higher where there is more soil moisture

(McMinn 1970). Seedlings will remain in a fire resistant “grass stage” for two (2) to five (5)

years. While in this grass stage the pines can re-sprout from the root collar after a fire (Ketcham

and Bethune 1963), allowing some to survive. Hofstetter (1973) reported that fires cause an 87%

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 7

mortality of seedlings less than five (5) feet tall and 50% mortality for those 6.6 to 19.8 feet tall.

Seedlings have improved survivability in areas with less duff accumulation (Klukas 1973).