Predicting establishment success for alien reptiles and amphibians: a role for climate matching

Abstract

We examined data comprising 1,028 successful and 967 failed introduction records for 596 species of alien reptiles and amphibians around the world to test for factors influencing establishment success. We found significant variations between families and between genera. The number of jurisdictions where a species was introduced was a significant predictor of the probability the species had established in at least one jurisdiction. All species that had been introduced to more than 10 jurisdictions (34 species) had established at least one alien population. We also conducted more detailed quantitative comparisons for successful (69 species) and failed (116 species) introductions to three jurisdictions (Great Britain, California and Florida) to test for associations with climate match, geographic range size, and history of establishment success elsewhere. Relative to failed species, successful species had better climate matches between the jurisdiction where they were introduced and their geographic range elsewhere in the world.Successful species were also more likely to have high establishment success rates elsewhere in the world. Cross-validations indicated our full model correctly categorized establishment success with 78-80% accuracy. Our findings may guide risk assessments for the import of live alien reptiles and amphibians to reduce the rate new species establish in the wild.

Establishment of introduced reptiles increases with the presence and richness of native congeners

“…Snakes showed a higher proportion of failed establishment in the presence and in the absence of native congeners than lizards. In general, snakes are considered the most harmful reptile taxa for humans, so governmental efforts may target snakes, which may influence their rates of establishment (Bomford et al, 2009). …”

“…This database has been used by other studies (e.g., Bomford et al, 2009;Tingley, Phillips and Shine, 2011;Richardson, 2011, 2012) and contains the large majority of the world's published accounts of introductions involving reptiles. Only introductions that took place outside of a species' native geographic range are included in the database.…”

“…Within the database, many records consist of multiple introductions of the same species to the same locality, but we considered establishment successful if at least one of these introductions was successful (as in Bomford et al, 2009). Taxa lacking identification at the species-level and unknown outcomes of the introduction (established or failed) were removed from our analysis.…”

First record of the exotic channel catfish Ictalurus punctatus (Rafinesque 1818) (Siluriformes: Ictaluridae) in the Rio dos Sinos basin, RS, Brazil

“…Of approximately 1,678 documented introductory events of 280 species of freshwater fish in the world, 70.9% resulted in the establishment of the species in the new environment (Bomford et al 2010). The introduction or transference of exotic and/or allochthonous species can result in the decline or extinction of native species (Rahel 2000).…”

Weighing empirical and hypothetical evidence for assessing potential invasive species range limits: a review of the case of Burmese pythons in the USA

“…Bomford et al (2009) proposed that climate matching can be a valuable tool for assessing risk of establishment by alien herpetofauna, and many researchers have been exploring and evaluating attributes for assessing establishment risk (Bomford et al 2009;Hayes and Barry 2008;Stohlgren and Schnase 2006). As with all statistics and modeling, the data upon which a model is generated and the analytical methods used to produce the results determine the accuracy and utility of inferences (Engeman et al 2011).…”