Of Mississippi’s original 9.87 million acres of natural wetlands, only about 4.07 million acres remain. Despite this loss of more than 58 percent of its wetlands, Mississippi still has such diverse habitats as marshes, swamps, riverbank pioneer habitats, bottomland hardwood forests, bayheads, coastal flatwoods, and savannahs.
Bottomland hardwood forests, swamps (forested or shrub wetlands), riverine wetlands, and fresh marshes (emergent herbaceous wetlands) account for the majority of Mississippi’s wetlands. Estuarine wetlands are the second-most-common wetlands in Mississippi and include tidal and estuarine marshes, freshwater marshes, salt pannes, sea grass beds, mud flats, and cypress–tupelo gum swamps.
Mississippi’s main wetland areas include the Gulf Coast, areas in the Lower Central Plain, and the Yazoo-Mississippi River Delta. The coastal area is level to gently sloping and is at sea level on the Gulf of Mexico. These wetlands are dominated by irregularly flooded black needlerush brackish marshes, patches of tidal salt marshes of cordgrasses, and farther inland, freshwater marshes with mixed plant species. In addition, the Gulf Coastal region has pond cypress–coastal evergreen swamps, wet pine flatwoods, and large marshy or boggy areas dominated by carnivorous plants, wax myrtle, and pine.
Inland from the coast, hilly Lower Coastal Plain upland depressions and river edges support tupelo gum and various broadleaf evergreens such as sweet bay magnolia, swamp bay, and titi (swamp cyrilla) in headwater bayheads, swamps, and stream margins. The soils are mostly sandy to loamy and are typically acidic. The shallow clear waters to the north of the extensive barrier islands support submerged beds of sea grasses—underwater meadows of grass-like plants.
The Yazoo-Mississippi River floodplain, known as the Delta, is home to some of the state’s major wetlands. It is delineated by the Mississippi River to its west, the Yazoo River to its southeast and south, and the Loess Hills to its east and northeast. The landscape aspect is low and very level (about 75 to 160 feet above mean sea level), and the entire region is dominated by bottomland hardwood forests composed variously of wetland oaks, sugarberry, hickory, pecan, sweet gum, elm, green ash, and red maple.
The Delta area also supports floodplain hardwood swamps, bald cypress–swamp tupelo–buttonball strands and swampy oxbow remnants, buttonball shrub swamps, and willow thickets. Pioneer communities of black and sandbar willows and cottonwood develop on sandy shoals and mudflats in its streams. The soils are alluvial in origin and vary from sandy to clayey and tend to be slightly acidic to alkaline.
- M. M. Brinson, A Hydrogeomorphic Classification of Wetlands (1993)
- L. M. Cowardin, V. Carter, F. C. Goulet, and E. T. LaRoe, Classification of Wetlands and Deepwater Habitats of the United States (1979)
- W. J. Mitsch and J. G. Gosselink, Wetlands (1986)
- Public Law 100–4, Federal Clean Water Act of 1987, sec. 404
- US Army Corps of Engineers, Environmental Laboratory, Corps of Engineers Wetland Delineation Manual: Technical Report Y-87-1 (1987)