Estimating the effect of beach nourishment on Caretta caretta (loggerhead sea turtle) nesting

Caretta caretta (loggerhead sea turtle) nesting activity was recorded daily during three seasons prior to and two seasons immediately following a beac h nourishment (replenishment) project in Palm Beach County, Florida. Survey s were done at the nourished beach (Jupiter/Carlin) and at two natural beac hes (Juno and Tequesta). The size of the nourishment effect on nesting acti vity was estimated using Before-After-Control-Impact Paired Series (BACIPS) models. Nesting declined by 4.4 to 5.4 nests km(-1) day(-1) on the nourish ed beach compared to the two natural beaches in the first season after nour ishment. At the same time, false crawls (FC, non-nesting crawls) increased by 5.0 to 5.6 FC km(-1) day(-1) on the nourished beach. In the second seaso n following nourishment, nesting was reduced by 0.5 to 1.6 nests km(-1) day (-1) on the nourished beach compared to the two natural beaches. The increa se in false crawl frequency in the second season following nourishment was 0.7 to 0.9 FC km(-1) day(-1). These results suggest that beach nourishment significantly decreased loggerhead sea turtle nesting during the first seas on following the project. However, the size of the effect, in terms of nest ing frequency and false crawl frequency, was much reduced by the second sea son following nourishment.