A swamp is any wetland dominated by woody plants. There are many different kinds of swamps, ranging from the forested red maple, (Acer rubrum), swamps of the Northeast, to the extensive bottomland hardwood forests found along the sluggish rivers of the Southeast. Swamps are characterized by saturated soils during the growing season, and standing water during certain times of the year. The highly organic soils of swamps form a thick, black, nutrient-rich environment for the growth of water-tolerant trees such as cypress (Taxodium spp.), Atlantic white cedar (Chamaecyparis thyoides), and tupelo (Nyssa aquatica). Some swamps are dominated by shrubs, such as buttonbush or smooth alder. Plants, birds, fish, and invertebrates such as freshwater shrimp, crayfish, and clams require the habitats provided by swamps. Many rare species, such as the endangered American crocodile depend on these ecosystems as well. Swamps may be divided into two major classes, depending on the type of vegetation present: shrub swamps, and forested swamps.
Functions & Values
Swamps serve vital roles in flood protection and nutrient removal. Floodplain forests are especially high in productivity and species diversity because of the rich deposits of alluvial soil from floods. Many upland creatures depend on the abundance of food found in the lowland swamps, and valuable timber can be sustainably harvested to provide building materials for people.
Due to the nutrient-rich soils present in swamps, many of these fertile woodlands have been drained and cleared for agriculture and other development. Over 70 percent of the United States' floodplain forested swamps have been lost. Many of the remaining mangrove swamps in Florida are threatened by residential development. Historically, swamps have been portrayed as frightening no-man's-lands. This perception led to the vast devastation of immense tracts of swampland over the past 200 years, such as the destruction of more than half of the legendary Great Dismal Swamp of southeastern Virginia.
Types of Swamps
Forested swamps are found throughout the United States. They are often inundated with floodwater from nearby rivers and streams. Sometimes, they are covered by many feet of very slowly moving or standing water. In very dry years they may represent the only shallow water for miles and their presence is critical to the survival of wetland-dependent species like wood ducks (Aix sponsa), river otters (Lutra canadensis), and cottonmouth snakes (Agkistrodon piscivorus). Some of the common species of trees found in these wetlands are red maple (Acer rubrum) and pin oak (Quercus palustris) in the Northern United States, overcup oak (Quercus lyrata) and cypress in the South, and willows (Salix spp.) and western hemlock (Tsuga heterophylla) in the Northwest. Bottomland hardwood swamp is a name commonly given to forested swamps in the south central United States.
Shrub swamps are similar to forested swamps, except that shrubby vegetation such as buttonbush, willow, dogwood (Cornus sp.), and swamp rose (Rosa palustris) predominates. In fact, forested and shrub swamps are often found adjacent to one another. The soil is often water-logged for much of the year, and covered at times by as much as a few feet of water because this type of swamp is found along slow-moving streams and in floodplains. Mangrove swamps are a type of shrub swamp dominated by mangroves In the United States, mangrove swamps are found only along the coast of the Gulf of Mexico, with the vast majority occurring in Florida. Small areas of mangrove swamp are found in Texas and Louisiana. In the United States, mangrove swamps are dominated by three species of mangrove: red mangrove (Rhizophera mangle), black mangrove (Avicennia spp.), and white mangrove (Laguncularia racemosa). Mangrove swamps are critically important as nurseries for many species of fish and shellfish, including many recreationally and commercially important species. Mangrove swamps also help reduce shoreline erosion and can shield inland areas from some of the damaging effects of hurricanes.
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