Beschreibung:
Aim Invasive species present negative impacts on native biodiversity at a global scale. A key goal of community ecology is to identify what drives invasiveness, but hypotheses relying on biotic mechanisms remain largely untested for many groups. Here we asked whether source and recipient communities of two highly successful invasive anurans (the bullfrog Lithobates catesbeianus and the cane toad Rhinellla marina) differ consistently from a taxonomic and/or functional standpoint. If affirmative, this pattern could suggest that taxonomic and/or functional distances between an invasive species and a potentially recipient community might influence the alien's invasive potential. Location World-wide. Methods Based on co-occurrence data of 1061 amphibian species, we compared 30 source to 30 recipient communities of bullfrogs and cane toads by means of biotic metrics that summarize taxonomic and functional diversity and the relative position of the invasive species within the community. We also included environmental drivers that reportedly influence invasibility (climate, resource availability, spatial heterogeneity, and propagule pressure). Results Both invasive species were functionally distant to their respective recipient communities; in contrast, community diversity did not explain much variation between source and recipient communities. Climate matching possibly influenced cane toad's but not bullfrog's invasiveness, and landscape factors had little relevance overall. Main conclusion This study advances the notion that the relative position of a recently introduced species within the native functional space may help predicting its invasive potential.