Climate change drives mountain butterflies towards the summits

Climate change impacts biodiversity and is driving range shifts of species and populations across the globe. To understand the effects of climate warming on biota, long-term observations of the occurrence of species and detailed knowledge on their ecology and life-history is crucial. Mountain species particularly suffer under climate warming and often respond to environmental changes by altitudinal range shifts. We assessed long-term distribution trends of mountain butterflies across the eastern Alps and calculated species' specific annual range shifts based on field observations and species distribution models, counterbalancing the potential drawbacks of both approaches. We also compiled details on the ecology, behaviour and life-history, and the climate niche of each species assessed. We found that the highest altitudinal maxima were observed recently in the majority of cases, while the lowest altitudes of observations were recorded before 1980. Mobile and generalist species with a broad ecological amplitude tended to move uphill more than specialist and sedentary species. As main drivers we identified climatic conditions and topographic variables, such as insolation and solar irradiation. This study provides important evidence for responses of high mountain taxa to rapid climate change. Our study underlines the advantage of combining historical surveys and museum collection data with cutting-edge analyses.

Automated summary

Climate change impacts biodiversity by driving range shifts of species and populations, particularly affecting mountain species. This study on mountain butterflies in the eastern Alps found that most cases showed recent increases in altitudinal maxima, with the lowest altitudes observed before 1980. Mobile and generalist species tend to move uphill more than specialist and sedentary species, with climatic conditions and topographic variables identified as main drivers. The study underlines the importance of combining historical surveys with cutting-edge analyses to understand the responses of high mountain taxa to rapid climate change.