Using Pathway Analysis to Inform Prevention Strategies for Alien Reptiles and Amphibians

Alien reptiles and amphibians are deserving of greater attention that has hitherto been bestowed upon them by managers and researchers. Eradication or control of established taxa will generally be infeasible, leaving prevention of introductions as the primary management tool for controlling herpetological invasions. I analyzed >5,700 introductions of alien reptiles and amphibians worldwide to obtain the pathway information necessary for design of informed prevention programs. Six pathways account for the large majority of introductions: accidental introductions via cargo and the nursery plant trade and intentional introductions for biocontrol, food use, the pet trade, and aesthetic purposes. Pathway importance varies taxonomically, temporally, and geographically. Unlike other taxa for which introductions have been dominated by either accidental pathways alone or intentional pathways alone, reptile and amphibian introductions involve a mix of both. Consequently, prevention programs must involve a two-pronged approach for these taxa: risk assessment of pathways for taxa introduced accidentally and risk assessment of species for taxa introduced intentionally. Because of variation in pathway importance, information on how taxonomic, temporal, and geographic variables co-vary with economic and social data may allow for predictive assessment of pathway risk for accidental introductions. In contrast, some predictive assessment of taxon risk was achieved using variables that measure climate-matching between native and introduced ranges, phylogenetic risk, and prior history of successful taxon establishment.