History

The Okefenokee Swamp has a long history of human occupation and man-made alterations. Native American artifacts dating back to 2,500 B.C. have been found in the swamp. The Seminoles were the last Native American tribe to inhabit the area. They were driven from the swamp between 1838-1842, during the Second Seminole War. The name Okefenokee is derived from a Native American term, meaning "land of the trembling earth". The definition refers to the swamp's unstable peat deposits which are known to shake when walking on their surface (U.S. FWS, 2008).

White settlers lived on the fringes of the Okefenokee in the 1800s. After a land lottery in 1820, settlers moved in the eastern, northern and western edges of the swamp. A few families inhabited the islands within the swamp from the 1850s until the early twentieth century. The settlers lived an autonomous lifestyle, making a living by cultivating small gardens, and hunting and fishing (Trowell, 2007).

Two major historical events significantly altered the swamp's habitat in the late 1800s and early 1900s. The Suwannee Canal Company purchased a large portion of the southeastern swamp in order to build a canal from the swamp to the St. Mary's River. The company planned to use the canal to transport virgin cypress to a sawmill on the Atlantic coast. Included in the company's plan was the intent to drain the swamp to enable cultivation of cotton, rice, and sugarcane. The company's attempt at drainage failed, but it succeeded in building eleven miles of the canal and logging cypress. The company ceased operations in 1897. Spoil banks from the dredging still exist today along the remnant of the canal, which serves as an access into the southeastern portion of the swamp (Niemeyer, 2002).

Another attempt at logging the swamp took place in the northwest region of the park. The Hebard Cypress Company built many miles of railroads into the area and by 1927 had removed most of the easily reached cypress trees. The Hebard Company ceased operations by 1927, but some smaller companies continued to log until the 1940s. Only a few stands of old-growth cypress remain in the Okefenokee today (Niemeyer, 2002).

The Hebard Lumber Company sold their property to the federal government in 1937, and the Okefenokee Wildlife Refuge was established by president Franklin D. Roosevelt the same year. The U.S. Fish and Wildlife Service began managing the swamp as the Okefenokee National Wildlife Refuge in the 1950s. Almost ninety percent of the refuge was designated a National Wilderness Area in 1974. In 1986, the refuge was recognized as a Ramsar wetland of international importance (Trowell, 2007).

Geologic and Geographic Features

Geology

The basin upon which the Okefenokee Swamp developed is much older than the wetland itself. The Okefenokee basin formed behind a ridge of the Wicomico Coastal Terrace. This coastal terrace is one of many terraces that formed parallel to the southeast coast when the ocean advanced inland during the Pleistocene intergalacial periods. The terraces often consist of a barrier island ridge on the eastern, seaward side with a marsh or lagoon behind the western edge of the ridge. Trail Ridge is an ancient barrier ridge which forms the eastern border of the Okefenokee Swamp basin. The body of this ridge is composed of coarse sand, comprised of heavy minerals. Ground-water leaching of ilmenite, a heavy mineral found within the ridge, caused the mineral to be enriched in titanium, an element of value to mining operations (Carver, 1986).

Trail Ridge and the Okefenokee basin sediments were deposited over the much older, Miocene age Hawthorn Formation. The Hawthorne Formation, consisting of thick impermeable calcareous clay, retained the water that eventually accumulated in the Okefenokee Swamp. During the Wisconsin glaciation period, the swamp basin was a dry environment; oak forests were common. Later, during the the Holocene, the climate warmed and became more humid. As glaciers receded and sea level and the groundwater level rose, precipitation and groundwater was held in the basin by the Hawthorn clay lining. Upland oak communities were replaced by longleaf pine. Low areas retained water year-round and broadleaved, water loving plants took hold along drainages and in depressions of the basin. Cypress trees moved into the swamp. As peat accumulated and raised the water table, the swamp forest moved away from the streams and lowlands, and spread out laterally and vertically. Higher areas of the basin between ponds and streams were eventually covered by swamp forest (U. S. FWS, 2006).

Topography

The topography within the Okefenokee basin and its drainage basin is mainly gentle, low relief. On the western and northwestern edge of the swamp, the Western Uplands slope toward the swamp's interior. Creeks of the upland area carry much of the precipitation that falls in the region into the swamp basin. The sandy barrier ridge,Trail Ridge, defines the swamp's eastern border. Ground-water from this barrier ridge flows into the swamp. Low islands or island-like ridges are found in the swamp's interior. On the southern border, a low ridge separates the Okefenokee and Pinhook Swamps. The division between the two swamps is barely distinquishable. It is difficult to discern where the Okefenokee Swamp ends and the Pinhook Swamp begins (Carver, 1986).

Habitats

The use of the term "swamp" to describe the Okefenokee is sometimes misleading. Some naturalists refer to the area as a bog swamp, because the mosaic of habitats include more than a tree-filled wetland. The habitats of the Okefenokee Swamp change through time in response to fire and water levels (Niemeyer, 2002).

Peat did not begin to accumulate in the swamp until approximately 7,000 years ago, many thousands of years after the swamp basin formed. Peat accumulations, as thick as 4.4 meters, can be found in the depressions between the islands and ridges of the interior. The peat, consisting of partially decayed plant matter, differs from the peat of northern bogs. Ninety percent of the peat volume in the swamp is comprised of cypress (Taxodium) and water lily (Nymphea). Cypress peat is found under shallow waters, while water lily peat forms under deeper water. The open, watery areas where water lilies thrive are called prairies. These open areas are thought to form when fire burns down through the peat which creates areas of open, deeper water. Fires in the swamp, usually set by lightening, occur often during severe droughts, which are common in the swamp area (Carver, 1986).

The expansive, marshy, prairies, usually lacking trees, are found mainly in the eastern part of the swamp. Scattered among the prairie habitat are deeper water areas such as lakes and watercourses. Thick peat deposits underlie the prairies and during droughts and periods of low rainfall, the peat may be exposed. Aquatic plants such as water lily and and golden club are common in the deeper water prairies and a variety of emergent sedges and grasses dominate shallower prairies. Three kinds of carnivorous plants are found in the prairies habitat. Virginia chain fern is often found in areas where sphagnum moss is prevelant. Numerous birds,alligators, turtles, frogs and snakes are also plentiful in this habitat (Niemeyer, 2002).

Peat sometimes rises from the swamp bottom to the surface and a peat mass, called a battery, will float on top of the prairie surface. The peat rises because methane produced in peat bottom forces unattached peat clumps to the water surface. Alligators may also contribute to the formation of batteries. Eventually, vegetation becomes established on a battery's surface, and the drier habitat supports a great diversity of plants. Batteries become stable when woody plants send down roots and anchor the battery to the swamp bottom. These firmer vegetated islands, called houses, support cypress, bays and a variety of shrubs. Some houses consist of only a small clump of cypress trees, but others are comprised of many vegetated acres. Some have been dated to over five hundred years old (Niemeyer, 2002).

The swamp forest habitat, defined as the wet areas populated with dense stands of trees, covers approximately half of the Okefenokee Swamp. Pond cypress and loblolly bay trees are the most common trees in this habitat, but other trees such as sweetbay, red bay, tupelo, and red maple intermingle in these areas. The northern and western regions of the swamp support most the swamp forest (Niemeyer, 2002).

Drier upland habitats include the higher parts of islands and the sandhill fringes of the swamp. Approximately seventy islands are found within the interior of the swamp, mainly in the southern half. Islands support a variety of vegetation, including slash and pond pine which tolerate the lower, wetter areas of the islands. Live oak and scrub oak are present on island ridges. Shrubby plants such as the saw palmetto and a wiregrass-flowering herb combination cover the forest floor. Longleaf pine stands also occur on the sandier uplands of the islands and on the sandhill uplands fringing the swamp. The longleaf pine was once the most prevalent pine of the Southeast. Extensive timbering of the pine and the control of natural fires has permitted other species to replace the longleaf pine. Longleaf pine environments of the swamp provide important habitats for the Florida black bear and the endangered red-cockaded woodpecker (Niemeyer, 2002).

The natural progression from open water to a forest upland community is not applicable to the Okefenokee Swamp. Natural fires have maintained the varied wetland mosaic. In the Okefenokee, fires interrupt the natural filling in of the swamp. The successional vegetation stages of watery prairie, to cypress swamp, to mixed cypress forest are interrupted when intense natural fires, during periods of drought, burn down through the peat and create open water areas in the prairies. However, fire suppression, prescribed burning, fire control, and canal and dam construction have impacted the fire regime in the wetland (Loftin, 2000).

Habitats in the Okefenokee Swamp. From left to right: A. Exposed peat in prairie. B. Peat rises to the top of the prairie surface to form a battery (center of photo). C. Houses are vegetated islands that form from anchored batteries. D. Swamp forest covers about one-half of the swamp (Photograph D - USGS, 2008).

Hydrology

Many elements play vital roles in a swamp's existence. The region's topography, the water that flows through the area, precipitation, and evapotranspiration all contribute to the Okefenokee Swamp's unique environments. Human alterations have also affected the amount of water flow and its variability in the wetland (Loftin, 1997).

The Okefenokee Swamp's watershed covers approximately 3,700 square kilometers. Seventy percent of the water entering the swamp comes from precipitation and surface runoff from the northwestern uplands. Evapotranspiration accounts for eighty percent of the wetland's water loss. Streams and rivers carry off the remaining percent. Three drainage basins are found within the watershed. The Suwannee River, located in the western region of the swamp, carries eighty five percent of the exiting flow. St. Mary's River in the southeastern area of the swamp carries eleven percent of the flow and a small portion (4%) is carried by Cypress Creek in the southwest corner. The influence of groundwater on water inflow and outflow is minimal (Loftin, 1997).

Most of the region's precipitation fall as rain during the summer months. The area receives approximately fifty inches of average annual precipitation. Autumn and early winter are usually dry. The water in the swamp is very acidic, possessing an average pH value of 3.7. The decaying vegetation of the swamp cause the water to be high in tannins, causing the water to be the color of iced tea. Shallow water depths characterize the swamp, with an average depth of two feet and rarely more than nine feet. (Gibbons, 1997) Water levels reach their lowest in June due to high evapotranspiration demands, and also in December during the region's dry season. Droughts occur approximately every 20 - 30 years, lasting a few weeks to a month. When normal rainfall returns, the areas that have had significant drawdown will respond quickly and return to their seasonal water levels within two to three weeks (Loftin, 1997).

At the end of the 19th century, the swamp was subjected to human alterations which affected its hydrology. Attempts were made to drain the swamp, and timber harvesting and peat mining were common. A more recent, controversial alteration, The Suwanne River sill, was constructed in the 1960s. This low earthen dam was constructed across the major channel where the Suwannee River exists the swamp in the southwestern area of the refuge. The United States Congress ordered the sill to be built in response to extensive wildfires that burned approximately eighty percent of the swamp during 1954 - 1955. The wildfires occurred during a severe drought. Landowners bordering the swamp suffered extensive loss.

The purpose of the sill was to impound water to prevent further fires from occurring. Concerns since the sill's construction have focused on the fact that the dam has had an effect on the vegetation community in the sill's area. Wildlife scientists have determined the sill disrupts the hydrologic environment, specifically the creation of an extended hydroperiod in the area near sill. Recent studies have shown that the sill has not excluded fire from the swamp. Presently, extensive repairs are needed on the sill and refuge officials are facing the dilemma of whether to remove or repair the structure. The provision of fire protection for privately held land surrounding the sill area and the established recreational uses associated with the dam complicates the decision (Loftin, 2000).

Flora and Fauna

Flora

There are roughly 600 species of plants in the Okefenokee Swamp. The plants thrive despite the highly acidic water. The swamp's vegetation depends on the release and conversion of nutrients through physical processes. Fire, UV light mediated decomposition and cycles of drought and floods shape the varied plant communities. Carnivorous plants have adapted well to the Okefenokee's phosphate-nitrogen poor soil. Three kinds of pitcher plants are found here: the hooded pitcher plant, the golden trumpet pitcher and the parrot pitcher plant. Other carnivorous plants include the bladderworts, butterworts and the sundews. Two common aquatic plants in the swamp's prairie are the golden club and the water lilly. Golden clubs, emergent perennials, are also known as neverwets because their waxy leaves repel water. Water lilies, even more common to the wet prairies of the swamp float in large communities on the top of the water.

The pond-cypress, (Taxodium ascendens), is the most common tree in the swamp. It has a broad base emerging from the water and a thin trunk. The tree's laterally growing roots and base knees protruding above the water help it adapt to life in the wet, peaty soils it inhabits. Other common trees include slash pine, loblolly-bay, blackgum, swamp bay, and sweet bay. Spanish moss, not a true moss, is often seen hanging from trees in the swamp. The plant is an epiphyte, an air plant, that is not a parasite. It is provided nourishment from the sun, airborone nutrients, and foliage of the tree. Virginia chain fern adapts well to the watery environment of the swamp. This primitive plant that can grow in standing water can reach up to four feet (Lenz, 1997).

	Left: Hooded Pitcher Plant is one of the three varieties of pitcher plant found in the swamp. Right: Bladderwort is another carnivorous plant found in the prairies.
	Left: Golden club, also called never-wet, is a common plant of the prairies. Right: Masses of beautiful water lilies float in the open wetland prairies.
	Left: Pond-cypress is the most common tree to the area (Photograph by Lenz, R., 1997). Right: Spanish moss, an epiphyte (air plant), can often be seen hanging from cypress trees (Photograph by Lenz, R., 1997).

Fauna

There are many conservation and management issues for the Okefenokee National Wildlife Refuge. Wildlife and habitat issues involve preserving the varied communities of the refuge, surveying and monitoring wildlife population, managing habitats to allow expansion of species, and contolling exotic species and pests. Inventorying perimeter upland communities and parnering with landowners adjacent to the refuge is also a strategy to improve the refuge habitat. Researchers from other countries conduct studies in this world renowned wetland. In addition, the forestry and biology programs of the refuge conduct wildlife surveys to identify population trends and develop wildlife data sets (U.S. FWS, 2008a).

The restoration and management of longleaf pine communities is essential to assure this valuable habitat is preserved. This fire dependent habitat has declined in the area because of clearing, absence of natural fires, timber harvesting and settlements. Understory species invade the longleaf pine habitat when the natural fire regime changes. Only scattered stands of pure longleaf pine communities remain in the upland perimeter of the swamp. The refuge recognizes the importance of these areas to many wildlife species such as the red-cockaded woodpecker, the indigo snake, and the gopher tortoise.

The habitat management of the uplands centers around the red-cockaded woodpecker. Refuge staff oversees the planting of 15,000 to 25,000 longleaf pines each year. Controlled fires are used in the area to promote growth and reproduction of plant life by removing or destroying of old plant life. This is to promote regeneration in areas and kill pine species that are not needed in the area. These measures of planting and preserving the area are done by various organized groups who understand the need for this wildlife habitat. Timber removal is also a routine task that is also performed every year. This removal is done commercially and averages around 6,000 cords of forest products per year that value around $200,000 (U.S. FWS, 2008b).

The swamp forest generates a lot of money for the surrounding area, therefore fire control is important to private land owners as well as the timber industry. In response to a need for a coordinated effort to fight fires, the Greater Okefenokee Association of Landowners (GOAL) was formed. This group focuses on decreasing the response times to the fires that occur in the area by working alongside the U.S. Forest Service and the Fish and Wildlife Service (U.S. FWS, 2000c).

Along with management issues come conservation issues that need to be addressed and carried out. Some of the necessary measures that are being performed in the area are he monitoring of black bear, amphibian, reptile, fish and wildlife population. Water quality and water levels are monitored in the area. An air quality monitoring site and a mercury deposition site is also maintained. The refuge staff also works at controlling exotic species and other invasive pests in the refuge (U.S. FWS, 2000c).

There are two future issues that concern the Okefenokee area. These two are the DuPont threat to the mining of Trail Ridge and the Suwannee River Sill. The Suwannee River Sill was built to impound water in the swamp to prevent wildfire damage that could spread to property owned by individuals that lived in the area bordering the refuge. The debate is whether to repair or remove the dam. Many believe that the manipulation of the natural flooding of the area around the sill is a problem. Others think that removal of this structure could result in greater complications that will affect the established recreational uses in the area. (Holliday, 1997) The goals and strategies of the Okefenokee refuge include maintaining the swamp's native wetland communities and restoring the river flood plain of the Suwanee River that has been affected by the sill. The refuge plans to remove concrete water control structures and breach the sill in four places (U.S. FWS, 2006).

The DuPont mining proposal has been the most recent major threat to the Okefenokee Swamp. In the 1990s the DuPont chemical company made plans mine for titanium in Trail Ridge, the sandy ridge on the eastern edge of the refuge. DuPont owns or leases about thirty-eight thousand acres in the vicinity. Their plans were met with an strong opposition from the local public, refuge staff, biologists and environmentalists. Concerned experts and public protested that the mining would damage the wetlands through altered surface and groundwater flow, increase air pollution and destoroy wildlife habitat. Eventually, DuPont decided to withdraw its plans to mine in the area with the stipulation the company be compensated for their land investment and the potential income that would have earned from the mine (Niemeyer, 2002).

Conclusion

The Okefenokee Swamp is known for its varied habitats and diversity of plant and animal species. The abundance of flora and fauna living within one refuge is a unique characteristic of the wetland. Protecting and managing the refuge from private development and industrial pressures is an important goal. Maintaining and restoring the many natural ecosytems is essential.

In conclusion the U.S. Fish and Wildlife Service, as well as other organizations and volunteers are working to preserve and maintain the Okefenokee Swamp. There are many measures that have to be implemented in order to resolve the conservation and management issues of the area.

References

Carver, R. E. 1986. Trail Ridge and Okefenokee Swamp. Geological Society of America Centennial Field Guide-Southeastern Section, 1986pp 331-334.

Gibbons, W. 1997. The Natural History of the Okefenokee Swamp, in: Okefenokee, The Natural Georgia Series, Issue 1. Georgia Wildlife Federation, URL: http://www.sherpaguides.com/georgia/okefenokee_swamp/natural_history/index.html

Holliday, P. 1997. The State of the Swamp: The Suwannee River Sill and DuPont's Mining Proposal Grab attention and Concern in the Okefenokee, in Okefenokee, The Natural Georgia Series, Issue 1. Georgia Wildlife Federation, URL: http://www.sherpaguides.com/georgia/okefenokee_swamp/suwannee_river_sill/index.html

Lenz, R. J. 1997. Flora and Fauna of the Okefenokee Swamp, in Okefenokee, The Natural Georgia Series, Issue 1. Georgia Wildlife Federation, URL: http://www.sherpaguides.com/georgia/okefenokee_swamp/wildnotes/index.html

Loftin, C. S., Aicher, Sara B. and Kitchens, W. M. 2000. Effects of the Suwanee River Sill on the Hydrology of the Okefenokee Swamp: Application of Research Results in the Environmental Assessment Process. USDA Forest Service Proceedings RMRS-P-15-VOL-3. URL: http://www.fs.fed.us/rm/pubs/rmrs_p015_3/rmrs_p015_3_102_110.pdf

Loftin, C. S. 1997. Okefenokee Swamp Hydrology. Proceedings of the 1997 Georgia Water Resource Conference, March, 1997. University of Gerogia, Athens, Georgia, URL: http://cms.ce.gatech.edu/gwri/uploads/proceedings/1997/LoftinC-97.pdf

Niemeyer, L. and Folkerts, G.W. 2002. Okefenokee. University Press of Mississippi, Jackson, Mississippi, 166p.

Okefenokee Swamp Park. 2008. Georgia's Natural Wonder Animals. URL: http://www.okeswamp.com/animals.htm

Trowell, C.T. 2007. Human History of the Okefenokee Swamp. The New Georgia Enclyclopedia.Georgia Humanities Council, University of Gerogia Press, URL: http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-691&hl=y

U. S. Fish and Wildlife Service. 2009. National Wildlife Refuge System Profiles, Okefenokee National Wildlife Refuge. U.S. Fish and Wildlife Service, URL: http://www.fws.gov/refuges/profiles/index.cfm?id=41590

U. S. Fish and Wildlife Service. 2009a. Okefenokee at a Glance. Okefenokee National Wildlife Refuge, U.S. Fish and Wildlife Service, URL: http://www.fws.gov/okefenokee/Okefenokee%20at%20a%20Glance%20webpage.pdf

U.S. Fish and Wildlife Service. 2009b. Federally Threatened and Endangered Birds found in Georgia. Georgia Ecological Services Field Offices, URL: http://www.fws.gov/athens/endangered/tebirds.html

U. S. Fish and Wildlife Service. 2008. Okefnokee National Wildlife Refuge, History of the Okefenokee Swamp. U.S. Fish and Wildlife Service, URL: http://www.fws.gov/okefenokee/History.html

U. S. Fish and Wildlife Service. 2008a. Okefenokee National Wildlife Refuge, Wildlife and Habitat Management. U. S. Fish and Wildlife Service, URL: http://www.fws.gov/okefenokee/biology.pdf

U. S. Fish and Wildlife Service. 2008b. Okefenokee National Wildlife Refuge, Upland Forest Management. U. S. Fish and Wildlife Service, URL: http://www.fws.gov/okefenokee/uplands.pdf

U. S. Fish and Wildlife Service. 2008c. Okefenokee National Wildlife Refuge, Greater Okefenokee Association of Landowners. U.S. Fish and Wildlife Service, URL: http://www.fws.gov/okefenokee/Goal.pdf

U. S. Fish and Wildlife Service. 2006. Okefenokee National Wildlife Refuge Comprehensive Conservation Plan.U.S. Department of the Interior Fish and Wildlife Service Southeast Region, URL: http://www.fws.gov/southeast/planning/PDFdocuments/OkefenokeeFinalCCP/Okefenokee%20Final%20CCP%20edited%20.pdf

U. S. Geological Survey. 2008. Ongoing Field Work at Okefenokee National Wildlife Refuge (2/5/01). U. S. Department of the Interior, U.S. Geological Survey, URL: http://fl.biology.usgs.gov/armi/Okefenokee/Okefenokee_Field_Work/fw.jpg