Bears without borders: Long-distance movement in human-dominated landscapes

Abstract

Conservation of wide-ranging species and their mobility is a major challenge in an increasingly fragmented world. Species are traditionally viewed as static conservation targets and the importance of securing long-distance movement of individuals is still underappreciated in conservation and policy. Here, we investigated large carnivore movements in humanized landscapes of Europe. We describe the movement of 6 GPS-tracked male brown bears, including one of the longest dispersal events recorded in this species. We looked at the relationships of bear movement paths with country borders, roads, built-up areas and habitat composition. The daily distance of resident individuals was 5.5 ± 4.4 km and almost twice as long in the dispersing subadult (9.3 ± 6.4 km). Maximum displacement of the disperser was 360 km (compared to 43.3 ± 13.0 km in resident bears). The resident bears moved within less than 10 km to built-up areas, while the dispersing bear stayed mostly at larger distances. The bears also frequently crossed roads (0–31 per month) and state borders (0–14 per month). The dispersing bear moved through four countries. A review of 29 cases and studies of large carnivore long-distance movements in Europe showed that transboundary movement represented over 96% of all cases; 9 extended over different populations and 10 over recolonization areas. Most documented cases of long-distance dispersal (52% of 21 individual cases) ended with the death of the animal (82% of confirmed deaths were human-caused, 46% were legal killings) before it could reproduce. Reproduction was documented only in 2 of the individual cases. We emphasize high conservation value of long-distance dispersers in large carnivore populations and the need to reevaluate how they are viewed and managed. We urge to consider wide-ranging, transboundary movements in conservation policies.