Predicting climate change effects on distributions of four amphibians at their southern margin and gap analysis for future nature reserve design

Background/Question/Methods

Climate change is among the proposed explanations for observed declines of amphibians. Moreover, climate change is likely to alter geographical distributions of protected species which may then overlap less with current nature reserves networks. This is particularly true for many amphibians due to relatively poor dispersal ability and strong philopatry. Typical climate models used for predicting future species distributions generally ignore local abiotic factors, and do not consider how future distributions will overlap with current nature reserves. Here, we employed bioclimatic envelope modelling that included local abiotic factors for studying climate change effects on distributions of four amphibians- Triturus vittatus vittatus, Salamandra infraimmaculata, Pelobates syriacus and Rana bedriagae- under different dispersal scenarios. The first three species are under conservation concern and are at their southern-most edge of distributions. Theory suggests that shifts in marginal populations should be one of the first signs of future responses to environmental changes. The aims of this study were to evaluate the effect of climate change on the availability of suitable habitat of the four amphibian species, identify the gaps in the existing Israeli nature reserves network, and evaluate potential future gaps due to shifts in distribution that may result from climate change.

Results/Conclusions

Our models predict range shifts and a decrease in both the extent and quality of the habitable area for these species due to climate change. Less than 10% of the highly suitable areas of T. v. vittatus and S. infraimmaculata are protected in the future scenario. In addition, regions that have the highest average probabilities of all four species co-occurring have little overlap with protected areas, both currently (26.1% overlap) and in the future (7.9%).  Under certain conditions, R. bedriagae is expected to disappear from this area. Our results highlight the importance of incorporating local abiotic variables into climate change modelling and for analysing the resultant distribution patterns with the current protected area network to account for species range shifts and improve connectivity between protected areas for facilitating dispersal.