Natural History of the Okefenokee Swamp
The largest swamp in North America, the Okefenokee Swamp covers roughly 700 square miles and is located in the southeastern corner of Georgia,
A mix of geological events, environmental variables, and human impact has shaped the character of the Okefenokee Swamp. More than sixty-five million years ago, during the Cretaceous geological period, the region was beneath the sea. Marine sediments produced a deep layer of sandy, nutrient-poor soils. In more recent geologic times the depression forming the basin of the present-day Okefenokee Swamp was presumably created by wave action associated with an offshore sandbar. Today the depression is filled with fresh water and peat to create what Seminoles called the "land of trembling earth."
In logging operations beginning in 1910 and lasting for a quarter of a century, thousands of cypress, pine, and red bay trees were removed from the swamp. Some were among the largest and oldest individuals of their kind left in the country. In 1937 U.S. president Franklin D. Roosevelt provided official protection from logging and development by establishing the Okefenokee National Wildlife Refuge, which constitutes about 80 percent of the swamp. The absence of roads helps to maintain the integrity of the swamp ecosystem; canoe trails are the primary travel routes through the swamp.
In the subtropical climate, rainfall is approximately fifty inches a year and is the source of most of the water entering the swamp from the more than 1,400 square miles of upland watershed. The clear, tannin-stained, highly acidic waters of the Okefenokee generally are shallow, normally ranging up to depths of less than ten feet and averaging only two feet.
Most (about 85 percent) of the water leaving the Okefenokee is carried by the Suwannee River to the Gulf Coast of Florida. The St. Marys River, which flows into the Atlantic, drains the remainder of the swamp.
Because of its immensity and its physical and chemical attributes, the Okefenokee Swamp has a blend of habitats
The combination of physical and chemical features also has molded the swamp's natural history. The low-nutrient and acidic conditions have created ideal habitats for carnivorous plants, which attract, capture, and digest animals to compensate. Several species of large pitcher plants as well as smaller sundews and butterworts, which capture insects with a gluelike surface film on their leaves, are scattered throughout the swamp. Also present are bladderworts, aquatic carnivorous plants with tiny air-filled traps, called bladders, which snap shut when mosquito larvae or zooplankton trip the hair trigger.
Birds and Mammals
The terrestrial and aquatic portions of the swamp support about thirty species of native mammals. Large terrestrial mammals include black bears, white-tailed deer, and bobcats. Smaller terrestrial carnivores are gray foxes, opossums, and raccoons.
Reptiles, Amphibians, and Fish
After birds, reptiles make up the most diverse group of vertebrates. American alligators and five species of venomous snakes are indigenous to the swamp, the most obvious and ecologically dominant being the alligator. The vocal communications of alligators during both day and night, coupled with protective maternal behavior,
The Okefenokee, with its continual array of
A diverse assemblage of freshwater fishes, representing fourteen different families, is also known to inhabit the swamp. Among the species are Florida gars, American eels, and Okefenokee pygmy sunfish. Bowfins, pickerel, and several varieties of catfishes are found throughout the swamp's waterways and standing wetlands.
Although every species of plant or animal in the Okefenokee Swamp also can be found in other regions of the Southeast, the collective biodiversity creates a wildlife array of natural history that is unparalleled. All life forms in the swamp and its surrounding areas have adaptations that permit the existence of high biodiversity living under the singular environmental conditions of the Okefenokee Swamp.
A. D. Cohen, D. J. Casagrande, M. J. Andrejko, and G. R. Best, The Okefenokee Swamp: Its Natural History, Geology, and Geochemistry (Los Alamos, N.M.: Wetland Surveys, 1984).
Whit Gibbons, "The Natural History of the Okefenokee Swamp," Georgia Wildlife 6, no. 1 (1997): 4-16.
Whit Gibbons, "The Spirit of Southeast Georgia," in The New Georgia Guide (Athens: University of Georgia Press, 1996), 565-93.
Frances Harper and Delma Presley, Okefinokee Album (Athens: University of Georgia Press, 1981).
Joshua Laerm and B. J. Freeman, Fishes of the Okefenokee Swamp (Athens: University of Georgia Press, 1986).
Joseph Michael Meyers, Community Structure and Habitat Associations of Breeding Birds in the Okefenokee Swamp, Okefenokee Ecosystem Investigations, Technical Report no. 11 (Athens: University of Georgia, Department of Zoology and Institute of Ecology, 1982).
Megan Kate Nelson: Trembling Earth: A Cultural History of the Okefenokee Swamp (Athens: University of Georgia Press, 2005).
Whit Gibbons, Savannah River Ecology Laboratory
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