PARENT SESSION
Symposium 5: Ecological Forces and Land Management Challenges for the Southeastern Landscape
Organized by: D De Steven and BS Collins
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Chatham Ballroom B.
Multiple disturbances and the dynamics of Southeastern coastal ecosystems.
Yoder, Carrie1, Platt, William *,1, Stanton, L.1, 1 Louisiana State University, Baton Rouge, LA
ABSTRACT- Large-scale disturbances that occur in close association may produce effects different from those of isolated disturbances. Novel effects on important species may result in long-term changes, especially in ecotones between plant communities. Although disturbances are often hypothesized to structure communities, predictions of combined effects of different types of disturbances do not exist for communities and ecotones in most landscapes. We develop concepts for interactive effects of hurricanes, fires, and sea level rise as the most prominent disturbances in current southeastern coastal landscapes. We initially summarize studies conducted in isolation, focusing on effects of wind damage during hurricanes, fire damage, prolonged flooding and increased salinity from sea level rise. We then combine the known effects to explore potential effects of interactions among these disturbances. Throughout we focus on predictions of short- and long-term effects of single and multiple disturbances that influence coastal fresh-water marshes and bottomland forests, as well as the ecotone between these communities. We apply these concepts to a gradual topographic gradient from a soft bottom marine community along a tidal creek through an open estuarine marsh, fresh water marsh, into bottomland and mesic hardwood forest in the Weeks Bay National Estuarine Research Reserve in Baldwin County, Alabama. We explore relationships between disturbances and their effects on dominant species in the ecotone between fresh-water marsh and bottomland hardwood forest, focusing on the dominant herbaceous species, Cladium jamaicense, and the dominant tree species, Acer rubrum. We apply the concepts regarding potential interactions between natural disturbances to predict community and landscape patterns expected at Weeks Bay National Estuarine Research Reserve.
Key words: Fire and hurricane disturbance, Ecotone, Multiple disturbances, Southeastern coastal ecosystem