Climate change disproportionately threatens alpine species, by reducing available habitat and by isolating their populations. These pressures are particularly relevant for rear-edge populations, which typically occupy more marginal habitat compared to populations at the core of species’ ranges. We studied Caucasian grouse Lyrurus mlokosiewiczi in the Caucasus ecoregion, a global biodiversity hotspot where this species is endemic, to understand potential climate change impacts on the species. Specifically, we assessed how climate change impacts rear-edge populations and how important these populations are for understanding range shifts and adaptive capacity under climate change. We used maximum entropy modelling to assess changes in the distribution of climatically-suitable habitat under present and 2070 climate conditions for the representative concentration pathways 8.5 (RCP8.5). Our results revealed that ignoring rear-edge populations leads to a significant underestimation of the future range (by about 14,700 km²). Rear-edge populations were better adapted to warmer climates compared to core populations, and ignoring them therefore also underestimates adaptive capacity. Preventing the loss of rear-edge populations should therefore be a priority for conservation planning in the face of climate change. Because the Caucasian grouse is associated with alpine mountain tops, conservation should focus on establishing connectivity between rear-edge and core populations (e.g., via transboundary corridors or assisted colonizations). Our study reveals how species distribution modelling can highlight the importance of rear-edge populations for mitigating climate change impacts on species of conservation concern.

Three datasets are provided:

1. A table of Caucasiain grouse (Lyrurus mlokosiewiczi) occurence locations used as input to the species dsitribution modelling (Caucasian-grouse-occurence-points.zip)

2. Maps of the current distribution of climatically-suitable areas for the Caucasian grouse using all occurence points for the full mode and core-population model (Current-habitat-distribution.zip)

3. A map of the future distribution of climatically-suitable areas for the Caucasian grouse using all occurence points for the full mode and core-population model (Future-habitat-distribution.zip)

Distributional maps were generated using Maxent, with future conditions represented by bioclimateic variables derived for 2070 using the Representative Concentration Pathway (RCP) 8.5 scenario and the Community Climate System Model version 4 (CCSM4). Each ZIP-file contains a readme file with further detail. We refer to the methods section and supporting information of the paper for a full description of the data collection and processing methods.