No hearts below the snow line: Snow loss and prey mismatch threaten alpine stoats under climate change

Climate change is profoundly affecting mountain ecosystems, yet its impacts on predator-prey dynamics remain poorly understood. In this study, we investigated the effects of climate change on the stoat ( Mustela erminea ), a cold-adapted predator whose seasonal white coat relies on snow cover for camouflage, and its specialized prey, the snow vole ( Chionomys nivalis ), in the Italian Alps. Using occurrence records and an ensemble of Species Distribution Models, we projected current and future distributions under the high-emission RCP 8.5 IPCC scenario to 2100. Snow cover duration and snow vole presence emerged as the most influential predictors of stoat distribution, together explaining over 64% of model variance. Our results forecast a severe 36% contraction in stoat range, primarily driven by a loss of snow cover and reduced spatial overlap with its prey. In contrast, the snow vole is expected to expand its range by 77%, particularly in northern sectors of the Alps. However, the stoat appears unable to track this expansion, suggesting a growing predator-prey mismatch. These findings indicate that despite its current Least Concern status in Italy, the stoat may warrant reclassification as Vulnerable under IUCN Criterion A3c. The study highlights the impacts of climate change on trophic interactions and moulting species in mountain ecosystems. We recommend the implementation of long-term monitoring programs and the use of innovative tools to improve stoat data collection. Conservation actions should prioritize high-elevation habitats and address broader anthropogenic pressures to support the persistence of stoats and other cold-adapted species in a warming alpine landscape.