Swamps are forested or shrub-dominated wetlands, usually associated with low-lying, periodically or permanently flooded areas around streams and rivers. Water flows through swamps, although the movement can sometimes be imperceptible. In southeastern North America, alluvial and floodplain swamp forests are sometimes extensive, and are typically dominated by such tree species as bald cypress (Taxodium distichum), water tupelo (Nyssa sylvatica), swamp tupelo (N. sylvatica), and eastern white cedar (Chamaecyparis thyoides). More northern temperate swamps are usually dominated by red maple (Acer rubrum), silver maple (Acer saccharinum), American elm (Ulmus americana), and green or swamp ash (Fraxinus pennsylvanica). Freshwater tropical swamps can support much-more diverse species of angiosperm trees, while tropical mangrove swamps support only a few tree species that are tolerant of the brackish water.
Swamps provide habitat for numerous species of animals, many of which have a specific requirement for this type of habitat. For example, swamps of bald cypress in southeastern North America used to support the now-extinct American ivory-billed woodpecker (Campephilus principalis principalis), and they still provide habitat for the pileated woodpecker (Dryocopus pileatus), red-shouldered hawk (Buteo lineatus), prothonotary warbler (Protonotaria citrea), Carolina wren (Thryothorus ludovicianus), and many other small birds. These swamps also provide nesting habitat for wood duck (Aix sponsa) and for colonies of wading birds such as herons and egrets (e.g., great blue heron, Ardea herodias, and common egret, Casmerodius albus) and wood stork (Mycteria americana). Cypress swamps also support mammals, including swamp rabbit (Sylvilagus aquaticus), white-tailed deer (Odocoileus virginianus), and panther (Felis concolor), along with many species of amphibians and reptiles, including the American alligator (Alligator mississippiensis).