Climate prevails over habitat in shaping northern range limits of European bats

Context Species presence is largely determined by climatic and habitat characteristics. For many European bat species, the northern range limit lies in Scandinavia, where species richness and abundance decline northwards. This pattern may primarily reflect direct climatic constraints from progressively colder conditions, or alternatively, habitat suitability. Objectives To investigate whether climate or habitat primarily limits bats at their northern margins. Methods We surveyed bats at 433 points across the Scandinavian Peninsula using passive acoustic methods, spanning major climatic zones and land cover types. Bat presence was recorded at 340 points, with calls assigned to nine species. Potential distribution modelling was applied to four highly detectable species: Cnephaeus nilssonii , Myotis daubentonii , Pipistrellus pygmaeus and Nyctalus noctula . We compared GLMMs using climate-only, habitat-only and combined habitat-climate predictors, generated potential distribution maps, and examined climate and habitat ordination spaces. Results Climate was a stronger predictor of bat occurrence than habitat, with temperature variables dominating the GLMMs, suggesting thermal constraints on species persistence at higher latitudes. Maps generated from habitat-only models predicted suitable areas far north of observed ranges, whereas climate-only and combined habitat-climate models better matched field observations. Ordinations showed that species occupied much of the available habitat space but a more restricted portion of available climate space. Conclusions Northern range limits of European bats appear primarily climatically constrained rather than habitat-limited. Suitable habitat seems to be available north of current distributions, but low temperatures likely prevent occurrence there. However, unmodelled environmental factors may also influence distributions. Ongoing warming may allow northward expansion, so monitoring bats at their northern range margins may provide a sensitive indicator of climate-driven biogeographical change.