Potential range and corridors for brown bear in the Eastern Alps, Italy

Although several techniques have been used to explore the spatial features of brown bear (Ursus arctos) range (e.g., potential distribution ranges, linkages between isolated sub-populations, and analyses of habitat suitability), quality and quantity of data have often constrained the usefulness of the results. We used 12 environmental variables to identify potentially suitable areas for bears in the Italian part of the Eastern Alps. We used Mahalanobis distance statistic as a relative index of the environmental quality of the study area by calculating for each pixel (250 meters) the distance from the centroid of the environmental conditions of 100 locations randomly selected within known bear ranges. We used different levels of this suitability index to identify potential optimal and sub-optimal areas and their interconnecting corridors. The model identified 4 major areas of potential bear presence having a total size of about 10,850 km2. Assuming functional connectivity among the areas and mean density for west European countries, the Eastern Alps could support 108-325 bears. Potential ranges were also compared with existing protected areas to evaluate gaps between bear range with adequate protection and range needing protection. Only 31 % of existing protected areas was found suitable for bears. We suggest that bear conservation will depend more on establishing and managing effective corridors than other protected areas.