Thijs van den Burg, University of Amsterdam
Duration: February 2015-June 2016

The Lesser Antillean iguana (Iguana delicatissima) is an endangered species that is threatened by habitat loss and hybridization with the invasive Green iguana (Iguana iguana). I. delicatissima has been extirpated on several islands and only few populations have not been invaded by the Green iguana. Information about these last remaining strongholds is essential to protect this species from extinction. Focussing on St. Eustatius, we caught nearly 80% of the known population and used genetic data to assess our research questions. We test if hybridization historically and/or currently occurs using mitochondrial and nuclear gene RFLPs. Data from 16 microsatellite loci is analysed to determine genetic diversity, population structure and effective population size. Molecular and morphological data were consistent, indicating all captured iguanas as pure I. delicatissima. However, compared to populations on Dominica and Chancel, extremely low levels of genetic diversity were found on St. Eustatius (HE=0.057). This indicates that this population is genetically depleted, probably caused by several bottleneck events. Furthermore, there is significant evidence for inbreeding (FIS=0.115) and weak structure (FST=0.019) within this population. Although free of hybridization, this population's low genetic diversity and low levels of recruitment could indicate that it suffers from inbreeding depression threatening its long-term survival