Invasive reptiles and amphibians (henceforth herpetofauna) impose severe ecological and socio-economic costs. The legal pet trade is a major source of introduced and established herpetofauna, where exotic pets are introduced either accidentally by escaping or deliberately through owner-assisted releases. While introductions are an essential stage in the invasion process, factors that influence the introductions of exotic vertebrates from the pet trade are scarcely researched. Subsequent stages such as establishment and spread have been more thoroughly investigated, though once populations reach these later stages, they become more expensive and difficult to manage. Therefore, it is important to understand what factors influence introductions to help guide policy and management to more efficiently target species that have a high potential of becoming introduced.
Here, we investigate the effects of ten biological and economic factors on introduction probability for pet herpetofauna. We first conduct an inventory of the species for sale on the herpetofauna pet market in the USA. Because such an inventory has yet to be done, we take the opportunity to characterize the herpetofauna pet market. We then compile life history traits, economic data, and introduction status of all species on the pet market. We used boosted regression trees (BRT) to explore the contributions of the factors towards explaining the pattern of exotic herpetofauna introductions.
Results/Conclusions
We identified 478 species of herpetofauna for sale, encompassing all major orders of reptiles and amphibians. The BRT (AUC = 0.82) analysis reveals that introductions of exotic pets are best explained by (i) how large the species grows after purchase, (ii) price, (iii) popularity of pet, and (iv) how long the species lives after purchase, respectively. In addition, our analysis shows that species that live longer than 9 years after purchase or grow more than 3 kg after purchase, have an increased probability of being introduced.
In summary, our analysis revealed that both biological traits and economic factors influence introductions of exotic pet herpetofauna. Our findings can be used by policy makers and practitioners to help target species with high potential for introduction through risk assessments, surveillance, and consumer education. In addition, our results can help decide which current and future species are best suited as pets, defined in relation to invasion risk.