Sydney Stephens, University of Trento

Large carnivore movement is restricted not only by physical infrastructure but by "social carrying capacity" as well. While biological suitability in the Alps is well-documented, integrating human acceptance, which can act as an invisible resistance layer rerouting dispersal, narrowing corridors, and suppressing realized range- into spatial connectivity models remains rare. We address this gap by combining spatiotemporal social data with biological movement to quantify the realized resistance bears face.

After reintroduction of brown bears (Ursus arctos) to the Central Alps 25 years ago, the population has grown (98 [CI: 86-120] in 2023), yet range expansion remains limited, failing to create connectivity for an Alpine-Dinaric metapopulation. Human-caused mortality comprises a major share of adult deaths, indicating social constraints may limit connectivity before ecological capacity is reached.

We analyze changes in acceptance through time and space with a rare longitudinal acceptance dataset containing data from before (-2 years) and after (+1, +22 years) reintroduction (n=1200-2000). We see a drop in mean tolerance across villages immediately post-reintroduction (+1.5 to -0.6) and later remained stable on average, but became spatially polarized with bear density and perceived damages.

We integrate acceptance surfaces with biophysical, recreation/mobility, and bear (telemetry and multi-source presence) data using Bayesian Additive Regression Trees to estimate permeability. This is converted to resistance surfaces and movement corridors with a monotonic cost transformation and circuit-theory analyses, validated against bear GPS movement and independent detections. This baseline enables future comparison with the Carpathians, where bears persist without extirpation history, for insights on historical drivers on present conditions.