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Basin Swamp - (synonyms: gum swamp, bay, bayhead, swamp).
Basin Swamp is
generally characterized as a relatively large and irregularly shaped basin that is not associated
with rivers, but is vegetated with hydrophytic trees and shrubs that can withstand an extended
hydroperiod. Dominant plants include blackgum, cypress, and slash pine. Other typical plants
include red maple, swamp redbay, sweetbay magnolia, loblolly bay, Virginia willow, fetterbush,
laurel greenbrier, Spanish moss, wax myrtle, titi, sphagnum moss, and buttonbush. Typical
animals include southern dusky salamander, cricket frog, little grass frog, chicken turtle, striped
mud turtle, ringneck snake, scarlet kingsnake, crayfish snake, cottonmouth, wood duck, hawks,
turkey, great horned owl, barred owl, pileated woodpecker, songbirds, gray squirrel, black bear,
raccoon, mink, river otter, bobcat, and white-tailed deer.
Soils in Basin Swamps are generally acidic, nutrient poor peats, often overlying a clay
lens or other impervious layer. The resulting perched water table may act as a reservoir releasing
groundwater as adjacent upland water tables drop during drought periods. The typical
hydroperiod is approximately 200-300 days. Basin Swamps are thought to have developed in
oxbows of former rivers or in ancient coastal swales and lagoons that existed during higher sea
Infrequent fire is essential for the maintenance of cypress dominated Basin Swamps.
Blackgum and hardwood dominated Basin Swamps burn less often, while pine dominated Basin
Swamps burn more frequently. Without fire, hardwood invasion and peat accumulation will
eventually create a Bottomland Forest or Bog. Typical fire intervals in Basin Swamps may be
anywhere from 5 to 150 years. Cypress and pines are very tolerant of light surface fires, but
muck fires burning into the peat can kill the trees, lower the ground surface, and transform a
swamp into a pond or lake.
Small Basin Swamps may be difficult to distinguish from large Dome Swamps. Basin
Swamps are often associated with and may grade into Wet Flatwoods, Hydric Hammock, or
Bottomland Forest. The species composition of Basin Swamps frequently overlaps with
Floodplain Swamp, Strand Swamp, and Baygall.
Like other wetland communities, normal hydroperiods must be maintained in Basin
Swamps. If water levels must be artificially manipulated, somewhat deeper than normal water is
not likely to do much harm, but extended hydroperiods will limit tree growth and prevent
reproduction. Shortened hydroperiods will permit invasion of mesophytic species and change
the character of the understory or will allow a devastating fire to enter which would drastically
alter the community. Occasional fires are necessary to maintain the cypress and pine
Basin Swamps are unsuitable for construction because of their extended hydroperiods
and peaty soils. Most have been degraded by timber harvests, and many have been drained or
polluted. Thus, very few pristine examples of Basin Swamp communities exist. Those that
remain should be adequately protected and properly managed.
Source: Florida Natural Areas Inventory and Florida Dept. of Natural Resources. 1990. Guide to the natural communities of Florida. Florida Natural Areas Inventory and Florida Dept. of Natural Resources, Tallahassee, FL. iv, 111 p.