Nesting ecology and interactions between local and international priorities for hawksbill sea turtle (Eretmochelys imbricata) conservation on the Pacific Coast of Central America.

摘要

Despite human interaction with the biophysical environment since the beginning of human history, traditional research generally studied human and natural systems separately when addressing human-nature interactions. The purpose of my research is to better understand the nesting ecology and interactions between local and international priorities for hawksbill sea turtle (Eretmochelys imbricata) conservation in El Salvador and Nicaragua, where >90% of eastern Pacific hawksbill nesting occurs. In the first study, I explained the realities experienced by coastal residents who share habitat with hawksbills in El Salvador and then identified and clarified implications of discrepancies between these realities and international priorities for hawksbill conservation. The main findings were 1) primary importance of hawksbills is economic value attached to egg sales, but deeper cultural connections exist, 2) egg purchase by hatcheries benefits hawksbills and humans and 3) opportunities for local residents to participate in decision-making are limited and should be increased. In the second study, I characterized the microhabitat preferences and repeatability of nest-site choice by hawksbills, and then clarified the implications of doomed egg relocation programs on gene pools of hawksbills. I found 1) hawksbills preferred nest sites with abundant vegetation on dynamic beaches in mangrove estuaries, 2) female hawksbills exhibited local adaptations to differences in nesting habitat and 3) individual hawksbills consistently placed nests under high percentages of overstory vegetation, but were inconsistent in nest placement related to woody vegetation borders. In the third study, I generated and analyzed thermal profiles of hawksbill nest environments and estimated the sex ratios and physical condition of hatchling hawksbills under natural and artificial conditions. The primary findings were 1) minimal differences in temperature existed between sand depths, 2) adjustment of nest depth is unlikely to compensate for climate change, 3) in situ clutches incubated at higher temperatures and produced less fit offspring and 4) egg relocation can contribute to recovery efforts. The findings of these studies offer insight into interactions between hawksbill population dynamics and local community development on the Pacific coast of Central America, and demonstrate the value of implementing an evidence-based approach to guide public policy and conservation strategies.