Does hunting-mortality risk affect landscape connectivity? Insights from brown bear movement ecology

Abstract

Landscape connectivity supports key ecological processes of animal populations by enabling movement and ensuring gene flow. Habitat corridors are crucial for facilitating connectivity but may expose transient individuals to high mortality risk in human-modified landscapes. Historically, intense hunting led to fragmentation of Scandinavian and Karelian brown bear Ursus arctos populations in Fennoscandia. Currently, the Finnish-Russian Karelian population is managed through legal hunting and shows limited gene flow toward the Scandinavian peninsula (Sweden and Norway). Using a two-dimensional modelling framework and long-term datasets, here we assessed landscape connectivity in the Karelian population range and whether hunting-related mortality risk affects intra-population connectivity toward Scandinavia. First, we used GPS data (2002–2014) from 37 bears to perform a step-selection analysis, derive a resistance surface, and model connectivity by circuit theory across Finland and Russian Karelia. Next, we used Finnish bear harvest data (1174 locations, 2002–2014) and resource selection functions to model hunting-mortality risk across Finland, which we integrated with previously identified corridors. Connectivity was highest in forests along central-eastern Finland, southern Finnish-Russian border, and southern Russian Karelia, while it was limited in the northern Finnish reindeer husbandry region, probably due to higher cover of shrubland/open areas. Hunting-mortality risk was highest throughout central-eastern Finland. About 44% of Finland's corridor area fell within high-risk zones, which may potentially constrain connectivity to Scandinavia by acting as functional barriers. To enhance connectivity with Scandinavia, conservation actions in Finland should minimise forest fragmentation and decrease hunting pressure, e.g., within corridors and by protecting females with offspring and solitary subadults.