Understanding the spread and impact of exotic geckos in the greater Caribbean region

Understanding the patterns and drivers of the spread of exotic species is necessary for limiting their distributions and minimizing their impacts on biodiversity. Species that are spread unintentionally versus intentionally present distinct management challenges that must be addressed with unique solutions. We assessed the spread and impact of exotic gecko species in the greater Caribbean region—a taxa and region predicted to be conducive to a high rate of unintentionally spread exotic species. From the literature, we compiled a database of exotic gecko introductions to the greater Caribbean region, recording the year of introduction, introduction pathway, establishment success, habitat use, and ecological impacts. Exotic gecko species introductions have increased exponentially over time and geckos from multiple biogeographic realms are now present in the greater Caribbean region. Species from distant realms were largely introduced intentionally to Florida via the pet trade, whereas Caribbean endemics were mostly introduced to other Caribbean islands through unintentional or unknown pathways. Regardless of the introduction pathway, most introductions resulted in established populations, usually in anthropogenic habitat. Furthermore, the exotics, Hemidactylus mabouia and H. frenatus, appear to be on the ‘winning’ end of most species interactions, including those with other exotics. Overall, our results show exotic geckos are spreading both unintentionally and intentionally with a strong potential to displace native gecko species and impact ecosystems as generalist predators. As eradication success is usually low, future conservation efforts should focus on elucidating ecological impacts and preventing new introductions through pathway-specific trade policy, financial incentives, and education.