Identifying climatic niche shifts and their drivers is important for the accurate prediction of the risk of biological invasions. The niches of non-native plants and birds have recently been assessed in large-scale multispecies studies, but such large-scale tests are lacking for non-native reptiles and amphibians (herpetofauna). Furthermore, little is known about the factors that contribute to niche shifts when they occur. Based on the occurrence of 71 reptile and amphibian species, we compared native and non-native realized niches in 101 invaded ranges at a global scale and identified the factors that affect niche shifts.
Global except the Antarctic.
We assessed climatic niche dynamics in a gridded environmental space that allowed niche overlap and expansion into climatic conditions not colonized by the species in their native range to be quantified. We analysed the factors that affect niche shifts using a model-averaging approach, based on generalized linear mixed-effects models.
Approximately 57% of the invaded ranges (amphibians, 51%; reptiles, 61%) showed niche shifts (≥ 10% expansion in the realized climatic niche). Island endemics, species introduced to Oceania and invaded ranges outside the native biogeographical realm all showed a higher proportion of niche shifts. Niche shifts were more likely for species that had smaller native range sizes, were introduced earlier into a new range or invaded areas located at lower latitudes than the native range.
The proportion of niche shifts for non-native herpetofauna was higher than those for Holarctic non-native plants and European non-native birds. The ‘climate-matching hypothesis’ should be used with caution for species undergoing niche shifts, because it could underestimate the risk of their establishment.