Barrier shoreline ecosystems are valuable components of the coastal landscape that are subject to a significant number of acute perturbations (e.g., tropical storm events) and chronic pressures (e.g., sea-level rise), and as a result often necessitate management efforts to maintain their functions and extent as desired by coastal managers. A critical aspect of such management efforts is to effectively establish appropriate vegetation species so that soils and sediments are not lost to erosional forces and that suitable habitat is provided to support key faunal species. Understanding how vegetation communities develop over time in created barrier shoreline habitats is important for determining overall project success and informing best practices for implementing management actions. To facilitate such understanding, an analysis of historic monitoring data for selected habitat types of three Louisiana barrier shoreline management projects (Trinity Island, New Cut, and West Belle Pass) was undertaken. Data was acquired through the State of Louisiana’s online data portal, filtered appropriately, and analyzed for key vegetation characteristics such as total vegetation cover, species richness, and vegetation community composition.
Results/Conclusions
Vegetation community characteristics appeared to vary as a function of time at all three restoration sites, but trends are particularly notable at Trinity Island, which was the oldest of the restoration projects included in this analysis. For Trinity Island, total vegetation cover in dune habitats was similar for the first two sampling periods as plants established in this harsh environment. A significant reduction in total vegetation cover was detected in the third sampling period, reflecting substantial impacts to the dune habitats due to the passage of two hurricanes in the previous year. Subsequent sampling periods indicated a return to a pre-hurricane extent of total vegetation cover, followed by total vegetation cover reaching its highest level approximately 14 years post restoration. Species richness at Trinity Island closely mirrored the pattern exhibited by total vegetation cover. Interestingly, ordination of dune habitat vegetation at Trinity Island clearly delineated a gradient of age post restoration, with cover from planted species (e.g., Panicum amarum and Cynodon dactylon) decreasing through time and cover of natural colonizers (e.g., Strophystyles helova and Rayjacksonia phyllocephala) increasing through time. These results demonstrate the utility of recurrent monitoring and integrated analysis to elucidate trends in key vegetation community characteristics at restoration sites.