PARENT SESSION
Poster Session 3: Aquatic Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 210 D, Level 2, Palais des congrès de Montréal
Fifty Years of vegetation change in estuarine coastal transitions across the northern Gulf of Mexico.
Shirley, Laura*,1, Battaglia, Loretta 1, Platt, William2, 1 Southern Illinois University-Carbondale, Carbondale, IL2 Louisiana State University, Baton Rouge, LA
ABSTRACT- Estuarine wetlands are some of the most productive and diverse ecosystems on earth and also some of the most threatened. Estuaries receive the cumulative impacts of watershed influences and are impacted locally by natural and anthropogenic disturbances. In addition, these systems at the marine-terrestrial interface are directly impacted by sea-level rise and coastal subsidence making them useful as first responders and gauges of future change. We compared 50 years of vegetation change at two contrasting coastal sites. Jean Lafitte National Historical Park and Preserve (JLNHPP), LA is located in the rapidly subsiding Mississippi Deltaic Plain, and Weeks Bay National Estuarine Research Reserve (WBNERR), AL is on the Gulf Coastal Plain. Spatiotemporal changes in vegetation zones were determined using two series of aerial photography and GIS analysis. Initial results indicate that the two sites are similar in physiognomy, but differ in the pattern and rate of vegetation change. Forests and marsh at JLNHPP are retreating, possibly due to relative sea-level rise. In addition, break-up of the marsh and canal-building have facilitated internal exposure to saltwater. In both sites, shrub species are encroaching upon the marsh, likely due to fire suppression. Altered fire regimes displace the marsh at both sites, while seaward losses further restrict the marsh at JLNHPP. Our comparative study shows that vegetation changes are not uniform along the Gulf of Mexico and suggests the need for process-based work that includes a wide array of sites representing geographic differences in land use, rates of subsidence, and disturbance regimes.
Key words: wetlands, coastal transitions, Gulf of Mexico, relative sea-level rise