A swamp is a type of wetland characterized by relatively deep and widespread areas of water when compared to other wetland varieties, such as a marsh. A wetland is an ecosystem that is intermediate between terrestrial (land) and aquatic (water) environments, with features of both types. In the United States, woody vegetation is considered characteristic of a swamp, but this feature is not necessarily present in those around the world. In addition to the United States, there are swamps in Brazil, Barbados, Indonesia, Russia, and several African countries. These wetlands can be broken into two main categories: forested and shrub swamps.
Often associated with a certain body of water, such as a lake or river, swamps typically have very low elevation. The water is usually slow-moving and tannic due to the presence of decaying plant matter. A swamp may feature several elevated areas of dry land known as hummocks. Some are dry during part of the year, and the soil quality varies widely.
Swamps are sometimes characterized according to the type of trees they feature. In the United States, there are conifer, hardwood, cypress, and mangrove swamps. One of the largest and best known in the country, the Okefenokee Swamp of Georgia and northeastern Florida, is a cypress swamp, while mangrove swamps are characteristic of Florida.
Because the swamp is a specialized and relatively rare ecosystem worldwide, it is home to many interesting and unusual varieties of plant and animal life, many of which have adapted to the environment. Trees and plants characteristic of the particular wetland environment are able to thrive in standing water, and typical fauna include the American Alligator and the African Lechwe, a type of antelope. Many areas are the target of conservation campaigns, although quite a few have already been destroyed, including 70% of those that once flourished in the United States. Both the Okefenokee and the Great Dismal Swamp of Virginia and North Carolina are National Wildlife Refuges.