The Coastal Wetlands of Louisiana
Wetlands are found in poorly drained areas along the edges of all continents. They are subject to sea level changes, storms, river discharges, and tides and may be directly and indirectly affected by humans. These productive and valuable ecosystems can be an important habitat for aquatic and avian species, are often capable of preventing flood damage, and may affect water quality. In order to qualify as a wetland for regulatory purposes in the U.S., the substrate is required to be saturated or covered by shallow water for a specific period during the growing season. Also, the substrate must be composed of hydric soils that support hydrophytes at least periodically (Cowardin et al. 1979).
The Louisiana coast contains 40% of the coastal wetlands in the United States (Boesch et al. 1994) and is where the Mississippi River debouches into the Gulf of Mexico. This is one of the largest rivers in the world, and drains some or all of 32 states as well as the southernmost portions of Canada (LeBlanc 1987). Over the last 7,000 years, the Mississippi River shifted east and west at least 5 times as the river found a less resistant path to the sea (Turner 1990). It transported and deposited sediments to create the Teche, Lafourche, Saint Bernard, Modern, and the Atchafalaya delta lobes (LCWCRTF & WCRA 1998). These deltaic substrates may overlay each other or become open water once again. The remaining portions are now wetlands covering thousands of hectares of wetland over the southeast part of Louisiana (LeBlanc 1987). At its maximum growth, the riverine delta covered 14,000 km2. Only about 7,000 km2 remains today. (THE LOUISIANACOAST) America's largest wetland community is losing its marshes and swamps to the Gulf of Mexico..................
