© 1990 by The Society for Integrative and Comparative Biology
Landscape Development and Coastal Wetland Losses in the Northern Gulf of Mexico1
Coastal Ecology Institute, Louisiana State University Baton Rouge, Louisiana 70803
The causes of the extensive (0.86%/yr; 288,414 ha/yr) and well documented dramatic and accelerating rate of coastal wetland loss in the northern Gulf of Mexico were investigated by an interdisciplinary university research team to discern the role of outer continental shelf development. The landscape changes and potential causal agents are emphasized herein. Natural driving factors include sea level rise and geological compaction, which appear to remain constant this century, and sediment supply from the Mississippi River which has declined by 50%,since the 1950s. Man-made influences include hydrologic changes from river diversions, flood protection levees, an extensive canal and spoil bank network, belowground fluid withdrawal and accidental and intentional impoundments. Wetland loss is not simply a geological phenomenon. Wetland plants hold sediments together, add to vertical accretion rates, withstand storm winds and waves, and assist in sediment trapping. Plant physiologic stress is documented where hydrologic changes occur, and much of the wetland loss could be attributed to the effects of soil waterlogging on plants, not to sediment deprivation.