The broad basin that now holds the Okefenokee Swamp, in southeast Georgia, was an arm of the Atlantic Ocean at the end of the Mesozoic Era. While the sea retreated millions of years ago, the basin's landscape has undergone a series of reincarnations, changing in concert with the regional climate. The current swamp ecosystem began to develop 7000 years ago, reflecting the onset of a warm, wet climate, averaging 55 inches of precipitation each year. Over this time, thick deposits of peat, formed by the decay of aquatic and semiaquatic vegetation, settled on the sandy basin floor, setting the stage for today's mosaic of ponds, wet prairies, drier scrub zones and tree islands; the latter, which include stands of blackgum, pond cypress, red bay, red maple and pine, are home to the endangered red-cockaded woodpecker.
The Okefenokee Swamp, covering 700 square miles, is drained primarily by the Suwannee River; the St. Mary's River drains the southeast corner of the refuge. Countless lakes, ponds and channels feed into these rivers and their vast shallows offer prime habitat for herons, egrets, ibis, bitterns, wood storks, gallinules, wood ducks, cottonmouths, snapping turtles and American alligators. River otters, black bear, beaver, mink, gray fox and marsh cottontails are among the resident mammals. More than 620 plant species inhabit the Swamp, including saw palmetto, sedges, water lilies and a fantastic variety of carnivorous plants (sundews, pitcher plants and butter-worts); in addition, coastal plants grow along Trail Ridge, the remnants of a sandy barrier island chain that runs along the eastern edge of the Swamp.
Though protected within the largest National Wildlife Refuge in the eastern U.S., the Okefenokee remains vulnerable to drought and wildfire, as we saw this spring. But these natural forces are vital to the health of this Wilderness, clearing excessive timber and opening new prairies. Without wildfire, this diverse wetland would gradually yield to the expanding forest, eventually becoming the Okefenokee Pinelands.