Impact of historical land use change on the brown bear habitat connectivity in the Polish Carpathians.

Background: Europe has undergone dynamic land use changes in recent decades that have affected the extent, quality, and connectivity of large carnivore habitats. However, the current distribution of large carnivores also depends on historical land use processes. In this article, we analyse the impact of historical land use changes on the potential connectivity of brown bear habitats in the region linking the western and eastern parts of the Carpathians, one of Europe's biodiversity hotspots. Methods: The analyses were conducted based on elevation, slope, and distance-based, land use-related variables representing four time periods: 1860s, 1930s, 1970s, and 2013, using cost surface and least-cost path analyses. We used two different approaches to create cost surfaces: weighted, where the weights differentiated between variables according to their relative importance, reflecting their role in either bear space selection or avoidance, and unweighted, where all the variables were treated as equally important. Results: The results of both approaches showed a gradual improvement in habitat connectivity for brown bears over time, driven by the increase in forest cover observed over the whole analysed period. However, the dynamics of these changes were much higher after the forced post-war resettlement in the 1940s. These tragic events resulted in the removal of settlements over large areas, substantially reducing human pressure and allowing brown bears to spread into new territories, expanding their habitats and creating new connectivity opportunities. We found that up to 40% of the current corridor was stable since mid-19th century. Our analysis shows that the current population decline in many rural areas of Europe may have positive implications for the habitats and population connectivity of large carnivores, but careful planning is needed to avoid negative interactions with local communities.