BGR Bundesanstalt für Geowissenschaften und Rohstoffe

Giraf

 

Coming soon: GIRAF 2011 Workshop

5. - 9. December 2011
Dar es Salaam, Tanzania
Organised by the IUGS-CGI and UNESCO
Hosting Organisation: SEAMIC

 

GIRAF: Geoscience InfoRmation AFrica. Logo

Swamp

 

A swamp is a wetland that is forested. Many swamps occur along large rivers where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation or soil saturation. The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps. In the boreal regions of Canada, the word swamp is colloquially used for what is more correctly termed a bog, fen, or muskeg. The water of a swamp may be fresh water, brackish water or seawater. Some of the world's largest swamps are found along major rivers such as the Amazon, the Mississippi, and the Congo.

A marsh is a wetland composed mainly of grasses and reeds found near the fringes of lakes and streams, serving as a transitional area between land and aquatic ecosystems. A swamp is a wetland composed of trees and shrubs found along large rivers and lake shores.

Historically, humans have drained swamps to provide additional land for agriculture and to reduce the threat of diseases borne by swamp insects and similar animals. Many swamps have also undergone intensive logging, requiring the construction of drainage ditches and canals. These ditches and canals contributed to drainage and, along the coast, allowed salt water to intrude, converting swamps to marsh or even to open water. Large areas of swamp were therefore lost or degraded. Louisiana provides a classic example of wetland loss from these combined factors. Europe has probably lost nearly half its wetlands. New Zealand lost 90 percent of its wetlands over a period of 150 years. Ecologists recognise that swamps provide valuable ecological services including flood control, fish production, water purification, carbon storage, and wildlife habitat. In many parts of the world authorities protect swamps. In parts of Europe and North America, swamp restoration projects are becoming widespread. Often the simplest steps to restoring swamps involve plugging drainage ditches and removing levees.

Swamps and other wetlands have traditionally held a very low property value compared to fields, prairies, or woodlands. They have a reputation for being unproductive land that cannot easily be utilized for human activities, other than perhaps hunting and trapping. Farmers, for example, typically drained swamps next to their fields so as to gain more land usable for planting crops.

Many societies now realize that swamps are critically important to providing fresh water and oxygen to all life, and that they are often breeding grounds for a wide variety of species. Indeed, floodplain swamps are extremely important in fish production. Government environmental agencies (such as the United States Environmental Protection Agency) are taking steps to protect and preserve swamps and other wetlands. In Europe, major effort is being invested in the restoration of swamp forests along rivers. Conservationists work to preserve swamps such as those in northwest Indiana in the United States Midwest that were preserved as part of the Indiana Dunes. The problem of invasive species has also been put into greater light such as in places like the Everglades.

The Atchafalaya Swamp at the lower end of the Mississippi River is the largest swamp in the United States. It is an important example of southern cypress swamp but it has been greatly altered by logging, drainage and levee construction. Other famous swamps in the United States are the forested portions of the Everglades, Okefenokee Swamp, Barley Barber Swamp, Great Cypress Swamp and the Great Dismal Swamp. The Okefenokee is located in extreme southeastern Georgia and extends slightly into northeastern Florida. The Great Cypress Swamp is mostly in Delaware but extends into Maryland on the Delmarva Peninsula. Point Lookout State Park on the southern tip of Maryland contains a large amount of swamps and marshes. The Great Dismal Swamp lies in extreme southeastern Virginia and extreme northeastern North Carolina. Both are National Wildlife Refuges. Another swamp area, Reelfoot Lake of extreme western Tennessee and Kentucky, was created by the 181112 New Madrid earthquakes. Caddo Lake, the Great Dismal and Reelfoot are swamps that are centered at large lakes. Swamps are often called bayous in the southeastern United States, especially in the Gulf Coast region.

Contact

    
Dr. Kristine Asch
Phone: +49-(0)511-643-3324
Fax: +49-(0)511-643-3782