Ski resorts threaten climate refugia for high-elevation biodiversity under current and future conditions in the Alps

Climate and environmental changes are dramatically impacting mountain ecosystems, species and livelihoods. Alpine species are contracting as a response to global change and human impacts. Climate refugia are crucial sites for conservation, because they will preserve suitable conditions for biodiversity in the face of climate change. Outdoor recreational activities (skiing in particular) are threatening mountain ecosystems, leading to conflicts with biodiversity. There is therefore a compelling need to investigate the spatial impact of ski resorts on climate refugia, which we evaluate under current and future conditions in the Alps, where those key conservation sites are exposed to human pressure and are often located outside protected areas. This information is key to prevent/reduce the impacts of ski resorts on climate refugia and increase skiing sustainability. Downhill ski-pistes occupy 489,119 ha in the Alps (average elevation 1792 m) and, if their immediate surroundings are also considered, the current overlap with climate refugia reaches 11 %, leading to additional strong fragmentation of high-elevation habitats, impairing connectivity. One out of three of current ski-pistes is associated with a possible impact on climate refugia and this situation will aggravate in the future. Ski-piste distribution will shift upwards (predicted elevational increase 271–609 m) because of climate change, leading to an increase in the overlap between suitable areas for ski-pistes and climate refugia (from 57 % under current conditions to 69 %–72 %). These results highlight the urgent need to preserve climate refugia and the climate-threatened biodiversity they host from environmental alterations caused by unsustainable development.