Measuring the effects of morphological changes to sea turtle nesting beaches over time with LiDAR data Kristina H. Yamamoto a, ⁎, Sharolyn J. Anderson b , Paul C. Sutton a,b a University of Denver, 2050 E. Iliff Ave., Denver, CO 80208-0710, United States b Barbara Hardy Institute and School of Natural and Built Environments, University of South Australia, Mawson Lakes, Adelaide, SA 5001, Australia abstract article info Article history: Received 14 November 2014 Received in revised form 30 June 2015 Accepted 1 July 2015 Available online 26 July 2015 Keywords: LiDAR Sea turtle Habitat Change analyses Coastal Sea turtle nesting beaches in southeastern Florida were evaluated for changes from 1999 to 2005 using LiDAR datasets. Changes to beach volume were correlated with changes in several elevation-derived characteristics, such as elevation and slope. In addition, these changes to beach geomorphology were correlated to changes in nest success, illustrating that beach alterations may affect sea turtle nesting behavior. The ability to use LiDAR datasets to quickly and efficiently conduct beach comparisons for habitat use represents another benefit to this high spatial resolution data. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Marine species that depend on beaches have adapted to the constant changes in beach morphology, but at some point the habitat may be altered too drastically to be available as suitable habitat. Sea turtles show strong natal homing (e.g. Green turtles, Chelonia mydas, Bowen et al. 1992, loggerhead, Caretta caretta Bowen et al. 1993). However, in- dividuals stray from these natal beaches (Carr and Carr, 1972; Tucker, 2010; Hays and Sutherland, 1991), indicating that fidelity to the natal beach, though strong, is not absolute. Entire populations may change nesting beach preferences, especially when changes to the beaches have caused the beach to become unsuit- able for nesting activities. The year immediately following artificial beach nourishment from imported sand, C. caretta and C. mydas showed a decrease in nesting activity (Brock et al., 2009). Factors such as erosion and deposition of offshore mud banks in French Guiana can result in the complete loss of sandy beaches suitable for nesting, while changes in river paths can create new nesting areas (Kelle et al., 2007). In such dy- namic areas, previously well-used nesting beaches can be abandoned, and other lesser-used beaches will suddenly support large numbers of nesting females (Kelle et al., 2007). It appears that slope, and the change of slope, in nesting beaches can also influence nesting activity. For C. caretta, higher nest densities are found in beaches with greater beach slopes, and for these nesting beaches, slope was inversely corre- lated with beach width (Provancha and Ehrhart, 1987). Mortimer (1982) hypothesized that slope and offshore configuration of the beach may be of importance to sea turtle nesting activity, although the values have been quantified. Nesting success, or the number of successful crawls (i.e. crawls that result in a nest), divided by the total number of crawls (Brock et al., 2009) is used to determine how changes in beach morphology affect sea turtle nesting behavior. The lower the nesting success, the less suit- able the nesting area, and the change in nesting success can serve as a method to establish beach suitability from one year to another (Brock et al., 2009). For a stretch of nesting beaches in Florida, post-hurricane dramatic restoration efforts (50–99% and 100% restoration) resulted in decreases in nesting success. These results were correlated with changes to beach profiles, in particular for slope and volume (Long et al., 2011). Nesting success is a preferable value to nesting numbers for beach suitability, as individual female C. mydas turtles most often nest every two or more years, and never consecutively (Broderick et al., 2001). Female C. caretta, however, can nest in subsequent years, or return every two to three years (Broderick et al., 2001). As a result of climate change and sea level rise, the low-lying beaches used by sea turtles for nesting are at risk of inundation, which may cause the extinction of entire populations (Fish et al., 2005, Fuentes et al., 2010). In addition, warming temperatures may skew the sex ratios, as a sea turtle's gender is determined by the temperature of the sand Journal of Sea Research 104 (2015) 9–15 ⁎ Corresponding author. E-mail addresses: khyamamoto@gmail.com (K.H. Yamamoto), Sharolyn.Anderson@unisa.edu.au (S.J. Anderson), paul.sutton@du.edu (P.C. Sutton). http://dx.doi.org/10.1016/j.seares.2015.07.001 1385-1101/© 2015 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Journal of Sea Research journal homepage: www.elsevier.com/locate/seares