Predicting future conservation areas while avoiding competition in two alpine urodele amphibians severely threatened by climate change

Abstract

Climate change will cause important declines in species distributions, especially when living at high altitudes. The Critically Endangered Salamandra lanzai from SW Alps may be severely exposed to future climate change effects and its suitable climate may shrink or shift. Another Alpine salamander (S. atra) is present in the region, which in case of spatial overlap may represent a competitor for S. lanzai. It is urgent to estimate the effect of future climate change on these species and identify priority areas for conservation while accounting for competition between both species. With a Species Distribution Modelling (SDM) approach, we projected the current and future climate suitability of both salamander species. We accounted for uncertainty related to the methods (model replicates) and climate projections (data source, global circulation model and scenario) to provide a consensus map for practitioners. This map also takes into account potential competition with S. atra by penalizing the suitability scores of S. lanzai by the scores of S. atra. We predict a severe effect of climate change on both species. Most of the current habitats are projected to become largely unsuitable by 2070, regardless of the climatology and scenario. We identified important spatial disagreements between projections based on different data sources, mostly due to precipitation projections and daily temperature variation. This highlights the need to account for multiple climatologies in mountainous environments. Both species' habitats are highly fragmented, which is expected to prevent distributional shifts through natural dispersion. We suggest to explore the possibility of translocation for the most threatened populations and simultaneously develop captive breeding programs. Biotic interactions are rarely accounted for in SDMs, and we encourage the documentation of species with similar ecological requirements to improve the relevance of SDMs for future conservation planning.