ABSTRACT
Coastal Louisiana contains vast wetlands that have a range of plant associations that reflect differences in freshwater inflow (Figure 6.1). Louisiana’s coastal marshes account for 44% of all coastal wetlands in the conterminous United States, including 39% of all coastal salt marshes (Field et al. 1988). Coastal ecosystems vary from place to place primarily because of differences in riverine inflow. For example, the Mississippi-Atchafalaya River system discharges 610 km3 freshwater into the Gulf of Mexico each year, representing approximately 80% of its freshwater inflow. The river system also carries a large quantity of sediment, nutrients, and carbon that affect physical and chemical conditions in those wetlands and adjacent coastal waters (Coleman 1989). On the other hand, the Florida panhandle receives much less freshwater, sediment, nutrients, and carbon; river deltas are smaller and beaches prevail there. Thus, spatial differences among areas within ecosystems (e.g., a salt or freshwater marsh) are a result of differences in freshwater inflow among these areas. The remainder of this chapter focuses on vegetation and nekton in coastal marshes with most examples coming from coastal Louisiana.
