These forests form on limestone outcrops with very thin soil;[2] the higher elevation separating them from other habitats such as coastal marshes and marl prairies.
[2] The pine rocklands are a critically imperiled ecosystem located in southern Florida, the Bahamas, Turks and Caicos Islands, and Cuba.
Its location in south Florida and throughout the Caribbean Archipelago straddles the southern and northern ends of the temperate and tropical flora ranges, respectively.
densa), a patchy subcanopy of palms and shrubs, and an extremely diverse herbaceous layer, growing atop Miami oolitic limestone.
[7] Limited reserves found in the Lower Keys are decreasing due to fire suppression and salt-water intrusion via rising sea levels.
[9] The pine rocklands in Miami-Dade County and Everglades National Park are found on limestone substrates along the Miami Rock Ridge, an exposed oolitic limestone matrix 2–7 meters above sea level that extends from northern Miami to the southern Everglades with disjunct sections in the Lower Keys.
The limestone of the Miami Rock Ridge was perfect for development, and subsequent drainage has led to a significant decrease in the water table.
The shrub layer near wet prairies and marshes is composed of wetland species such as Acacia pinetorum, Sambucus canadensis, and Taxodium ascendens.
The herbaceous layer is extremely diverse and home to several species considered rare, endangered, threatened or critically imperiled by one or more agencies.
[8] Many species found in rocklands throughout south Florida are restricted to individual plots or to specific regions due to changes in soil type, extreme fragmentation, and fire suppression.
[23] These fires help curb hardwood encroachment, spur pine regeneration, and allow light to reach the herbaceous layer.
Presently, many isolated pine rockland sites throughout Miami-Dade County and the lower Keys suffer from fire suppression, leading to drastically altered plant compositions.
[30] Canopy species include gumbo-limbo (Bursera simaruba), paradise tree (Simarouba glauca), pigeonplum (Coccoloba diversifolia), Florida strangler fig (Ficus aurea), false mastic (Sideroxylon foetidissimum), willow bustic (Dipholis salicifolia), short-leaf fig (Ficus citrifolia), false tamarind (Lysiloma latisiliquum), West Indian mahogany (Swietenia mahagoni), and pepperleaf sweetwood (Licaria triandra).
Plants such as black ironwood (Krugiodendron ferreum), inkwood (Exothea paniculata), lancewood (Damburneya coriacea), marlberry (Ardisia escallonoides), poisonwood (Metopium toxiferum), satinleaf (Chrysophyllum oliviforme), white stopper (Eugenia axillaris), shiny oysterwood (Gymnanthes lucida), wild coffee (Psychotria nervosa), shortleaf wild coffee (Psychotria tenuifolia), and pale lidflower (Calyptranthes pallens) grow in the understory.
The clearing of large tracts for development has now reduced the pine rocklands to about 20,000 acres (81 km2), most of which are now protected inside the Everglades National Park.