LiDAR-derived measures of hurricane- and restoration-generated beach morphodynamics in relation to sea turtle nesting behaviour

Abstract

Coastal ecosystems provide sea turtle nesting habitat, and thus their maintenance is vital to promote conservation of the species. Before and after a very active hurricane season, airborne Light Detection and Ranging (LiDAR) was used to quantify the topographic dynamics of a critical nesting beach in east central Florida, USA, that was subjected to erosion and restoration. The surface area and volume of the beaches along a 41 km stretch, which is home to the highest concentration of loggerhead and green turtle nests in North America, differed significantly between pre- and post-hurricane and between pre-hurricane and post-restoration periods. Sea turtle nesting success (nesting emergences : total emergences) in the season after the hurricanes was correlated with various LiDAR-detected characteristics to determine how sea turtles responded to beach dynamics resulting from the storms and subsequent restoration. We found that the more the shape of the beach profile was altered from its pre-hurricane morphology, the more nesting success decreased.

Acknowledgements

Thanks to NOAA, the SJRWMD, the Joint Airborne LiDAR Bathymetry Center of Expertise of the US Army Corps of Engineers and the University of Central Florida Marine Turtle Research Group, directed by L.M. Ehrhart, for the use of their data, to L. McCauley for ArcGIS support and to K.M. Borrowman, D.A. Bagley, J.M. Fletcher and S. Ceriani for additional guidance.