Verified non-indigenous amphibians and reptiles in Florida from 1863 through 2010: Outlining the invasion process and identifying invasion pathways and stages

Abstract

We follow a biological invasion model that consists of a series of five consecutive obligatory stages, concluding with stages 4a and 5 (i.e., widespread = invasive species). The State of Florida is infamous for having the most introduced (stages 2–5) amphibians and reptiles in the United States. However, there is disagreement regarding their numbers as well as identification in some cases. Unverified claims of species being introduced (stage 2), or established (stages 3–5) without evidence (i.e., a voucher specimen or photograph) are prevalent in the literature. It is crucial to provide data on all known non-indigenous herpetofaunal species via vouchers to help keep numbers of species consistent, accurately identify species, document when and where a particular species is found, and identify the invasion pathway and current invasion stage of each species. In this study, we use vouchers to confirm interceptions and introductions of all known non-indigenous amphibians and reptiles in Florida from 1863 through 2010, provide a list of these species along with their invasion pathways and current ecological status (i.e., invasion stage), and provide a species account for each newly confirmed species. We include species that were previously reported in the literature but lacking an associated voucher and provide greater details on previously reported species and those species whose invasion stage has been upgraded to established (stages 3–5). Based on nearly two decades of field work along with examination of museum records and literature, we confirm three intercepted and 137 introduced amphibian and reptile taxa in Florida. Of these, 56 are established (i.e., reproducing; stages 3–5), including three frogs, four turtles, one crocodilian, 43 lizards, and five snakes. Of 149 total independent introduction pathways (i.e., including a different pathway one time only for each taxon) for the 140 total non-indigenous taxa above, two (1.34%) are related to the biological control pathway, four (2.68%) to the zoo pathway, 18 (12.08%) to the cargo pathway, and 125 (83.89%) to the pet trade pathway. Florida now ranks as having the largest number of established non-indigenous herpetofaunal species in the entire world. Despite current state laws that make it illegal to release any non-indigenous animal in Florida without first obtaining a permit from the Florida Fish and Wildlife Conservation Commission, enforcement is difficult, and no person has ever been prosecuted for the establishment of a non-indigenous animal species in Florida. Because current state and federal laws have not been effective in curtailing the ever-increasing number of illegal introductions, laws need to be modified and made enforceable. At the very least, those responsible for introductions should be held accountable for compensation to clean up (= extermination) of those species for which they are responsible. Lastly, we strongly support the creation of an Early Detection and Rapid Response program to quickly identify newly found introduced species for eradication attempts. This paper will also serve as a baseline to document future introductions.