Elevation Controls on Soil Properties and Vegetation Within a Gulf Coast Beach Ridge Complex.

Coastal restoration in Louisiana has assumed greater importance in the wake of recent severe hurricane landfalls.  One area slated for restoration is the Caminda-Moreau maritime beach ridge complex, a series of westard-trending parallel ridge sets formed during the Mississippi River Lafourche delta cycle.  Elevation data was gathered with survey-grade differential GPS techniques and 30 cm surface soil samples were collected at 103 locations varying in elevation from 2.3 – 80.5 cm (NAVD 88).  Dominance data was used to produce a relevant species list and plotted against elevation in five elevation catagories.  Elevation was significantly correlated to a number of soil properties including total C, N, P, salinity, organic matter, pH and bulk density.  Herbaceous species dominance decreased with increasing elevation and shrub dominance increased.  Live trees were only present in the highest elevation category.  Results suggest as coupled subsidence and increasing sea level continue, vegetation will continue to shift to more salt-tolerant herbaceous species with a loss of ecosystem complexity unless restoration efforts input sediment to increase elevation to overcome rising sea level.