Coastal species around the world face habitat loss from accelerated sea level rise, subsidence, and erosion due to wave action. Coastal marsh habitat and barrier islands are already beginning to disappear, and with them prime habitat for colonial nesting waterbirds. Even remaining habitat may not be ideal, with decreasing elevation leading to frequent overwash events which can wipe out whole colonies. We collected data on the location, elevation, primary vegetation type, nest height, and nest success of four species of colonial nesting waterbirds in Coastal Louisiana. Preliminary data show that island overwash is a primary cause of nest loss for all species, especially Forster’s Terns (Sterna forsteri), a species of concern in Louisiana.
Results/Conclusions
Approximately 30% of the 291 Brown Pelican (Pelecanus occidentalis) nests observed were overwashed, 28% of the 25 Roseate Spoonbill (Platalea ajaja) nests, and 100% of the 149 Forster’s Tern nests. Only Tricolored Heron (Egretta tricolor) nests were relatively safe from overwash, although the toll on chicks old enough to leave the nest but not yet fledged was difficult to assess. We also analyzed past data from a nearby NOAA station to model potential flood risk for these colonies with the intention of finding an ideal elevation for a future restoration project.