Coastal berm is a short forest or shrub thicket found on long narrow storm-deposited ridges of loose sediment formed by a mixture of coarse shell fragments, pieces of coralline algae, and other coastal debris. These ridges parallel the shore and may be found on the seaward edge or landward edge of the mangroves or further inland depending on the height of the storm surge that formed them. They range in height from 1 to 10 feet. Structure and composition of the vegetation is variable depending on height and time since the last storm event. The most stable berms may share some tree species with rockland hammocks, but generally have a greater proportion of shrubs and herbs.345 Tree species may include gumbo limbo (Bursera simaruba), seagrape (Coccoloba uvifera), silver palm (Coccothrinax argentata), blolly (Guapira discolor), milkbark (Drypetes diversifolia), sevenyear apple (Genipa clusiifolia), and poisonwood (Metopium toxiferum). Characteristic tall shrub and short tree species include Spanish stopper (Eugenia foetida), hog plum (Ximenia americana), white indigoberry (Randia aculeata), Florida Keys blackbead (Pithecellobium keyense), and saffron plum (Sideroxylon celastrinum). Short shrubs and herbs include perfumed spiderlily (Hymenocallis latifolia), bayleaf capertree (Capparis flexuosa), buttonsage (Lantana involucrata), and rougeplant (Rivina humilis).
Coastal strand is an evergreen shrub community growing on stabilized coastal dunes in the peninsula of Florida, often with a smooth canopy due to pruning by salt spray. It usually develops as a band between dunes dominated by sea oats (Uniola paniculata) along the immediate coast, and maritime hammock, scrub, or mangrove swamp communities further inland. On broad barrier islands or prograding coasts, it may also occur as patches of shrubs within a coastal grassland matrix. Soils are deep well-drained sands and may be somewhat alkaline, consisting of quartz sand mixed with varying proportions of shell fragments.
Along the Atlantic coast, species composition of coastal strand changes from north to south. Temperate species dominate from the Georgia border south to Cape Canaveral, with dense saw palmetto (Serenoa repens) and scattered dwarfed cabbage palm (Sabal palmetto) on the seaward edge, which are gradually joined inland by taller shrubs, including tough bully (Sideroxylon tenax), yaupon (Ilex vomitoria), Hercules’ club (Zanthoxylum clava-herculis), and shrubby forms of red bay (Persea borbonia), red cedar (Juniperus virginiana), and live oak (Quercus virginiana). From Canaveral southward tropical species become more prevalent, including seagrape (Coccoloba uvifera) nearest the coast, joined further inland by Florida swampprivet (Forestiera segregata), myrsine (Rapanea punctata), buttonsage (Lantana involucrata), white indigoberry (Randia aculeata), snowberry (Chiococca alba), Spanish stopper (Eugenia foetida), blolly (Guapira discolor), wild lime (Zanthoxylum fagara) Florida Keys blackbead (Pithecellobium keyense), coco plum (Chrysobalanus icaco), coinvine (Dalbergia ecastaphyllum), yellow necklacepod (Sophora tomentosa var. truncata), and gray nicker (Caesalpinia bonduc). Joewood (Jacquinia keyensis) is found only on the west coast and saffron plum (Sideroxylon celastrinum), of limited occurrence on the east coast, is common here.
Maritime hammock occurs on deep well-drained acid quartz sands or well-drained, moderately alkaline quartz sands mixed with shell fragments. It is a predominantly evergreen hardwood forest growing on stabilized coastal dunes lying at varying distances from the shore. Species composition changes from north to south with temperate species dominating from the Georgia border to Cape Canaveral and tropical species increasingly prevalent south of Cape Canaveral.
From the Georgia border to north of Cape Canaveral, live oak (Quercus virginiana), cabbage palm (Sabal palmetto), and red bay (Persea borbonia) combine to form a dense canopy. Additional canopy species include pignut hickory (Carya glabra) and southern magnolia (Magnolia grandiflora). Characteristic subcanopy species are red cedar (Juniperus virginiana) and American holly (Ilex opaca). Yaupon (Ilex vomitoria), tough bully (Sideroxylon tenax), wax myrtle (Myrica cerifera), and saw palmetto (Serenoa repens) are typical shrubs.
South of Cape Canaveral, tropical trees found in the canopy include gumbo limbo (Bursera simaruba), false mastic (Sideroxylon foetidissimum), inkwood (Exothea paniculata), white stopper (Eugenia axillaris), strangler fig (Ficus aurea) seagrape (Coccoloba uvifera), Spanish stopper (Eugenia foetida), poisonwood (Metopium toxiferum), blolly (Guapira discolor), and Florida Keys blackbead (Pithecellobium keyense); tropical shrubs include myrsine (Rapanea punctata), Simpson’s stopper (Myrcianthes fragrans), marlberry (Ardisia escallonioides), wild coffee (Psychotria nervosa), snowberry (Chiococca alba), and white indigoberry (Randia aculeata).
On the Gulf coast from Pasco to Lee counties, temperate canopy species exist with tropical understory shrubs. Farther south, more tropical trees are found in the canopy, including Jamaican dogwood (Piscidia piscipula) which is absent from the east coast. Along the Florida Panhandle, maritime hammock is found only in isolated pockets, often where shell is mixed with the sandy substrate.
Shell mounds are small hills, usually in coastal locations, composed entirely of shells (clams, oysters, whelks) discarded by generations of Native Americans. A rich calcareous soil develops on the deposited shells which supports a diverse hardwood forest on undisturbed mounds. Central Florida mounds are often characterized by tropical species occurring north of their normal range. On Turtle Mound at Canaveral National Seashore in Volusia County tropical trees such as white stopper (Eugenia axillaris), sea torchwood (Amyris elemifera), wild lime (Zanthoxylum fagara), false mastic (Sideroxylon foetidissimum), inkwood (Exothea paniculata), and lancewood (Ocotea coriacea) were recorded at or near their northern range limits. Shell mounds on the Cedar Keys in Levy County on the Gulf coast are also northern outposts for tropical species including white stopper, Florida swampprivet (Forestiera segregata), snowberry (Chiococca alba), and saffron plum (Sideroxylon celastrinum). Shell mounds in the Florida Panhandle support temperate canopy trees such as live oak (Quercus virginiana) and cabbage palm (Sabal palmetto) as well as calcium-loving temperate species not found in nearby maritime hammocks on sand, including soapberry (Sapindus saponaria) and Carolina buckthorn (Rhamnus caroliniana).
Source: Guide to the Natural Communities of Florida, 2010 Edition