Alien Reptiles and Amphibians: Early Progress Toward Predicting Risk Session 2: Science and Economics of Pre-Import Screening for Animal Species

Alien reptiles and amphibians have been relatively little studied compared to other classes of vertebrates. This appears largely due to the fact that most species are cryptic and difficult to notice and because they do not often directly impact humans or their domesticated animals. I compiled a global database of alien reptile and amphibian introductions (with an “introduction” being the human transport and release of an organism outside of its native range and, hence, not under direct human control) in order to better assess how these species are being introduced and to use the data to identify parameters useful for risk assessment (Kraus, in review). These data indicate that reptiles and amphibians have been widely introduced by humans, with at least 5745 introductions of 675 taxa documented in the literature, of which 1060 populations of 322 species have become successfully established. The rate of introduction is increasing exponentially, with a doubling time of just over 27 years (Kraus, in review). Furthermore, although only five populations of alien herpetofauna can be characterized as having been well studied ecologically, a broad diversity of damage is documented to attend the introduction of alien herpetofauna, including ecological, evolutionary, economic, and human-health impacts. As a result of both the rapid growth rate in introductions and the diversity of documented impacts, alien herpetofauna merit sustained management and research attention.