Where to go? Habitat preferences and connectivity at a crossroad of European brown bear metapopulations

Abstract

Natural habitats become increasingly degraded and fragmented due to rapid human expansion. The decreasing availability of high-quality habitats combined with a lack of connectivity among suitable patches and the low permeability of human-transformed landscapes endangers the survival of many species. Understanding the environmental conditions favoring a species’ distribution and the identification of movement corridors between populations is crucial for sustainable conservation and management. Serbia is the only European country inhabited by three different brown bear metapopulations, highlighting its crucial geographical position for establishing functional connections among these metapopulations. We used species distribution modeling to predict suitable habitats for the three bear metapopulations in Serbia at two spatial scales (5 and 1 km2). We combined the predictions from each metapopulation to define suitable habitats for range expansion. Further, we created landscape resistance maps to identify possible connectivity areas to promote gene flow between these metapopulations. Our results highlight that 1) the underlying processes of bear habitat selection at the coarse scale differ between metapopulations, mainly due to the differences in habitat availability; 2) > 60% of areas predicted as suitable for bears in Serbia are currently still unoccupied; 3) the south-eastern part of Serbia represents a key area for the connectivity between bear metapopulations in the future. However, the presence of several movement barriers, such as highways, highlights the need to implement adequate mitigation measures to increase habitat permeability. Because bears are a useful umbrella species for conservation actions, improvement of habitat quality and permeability will also positively affect many other species in this region.