Prey Occupancy and Functional Connectivity in Biological Corridor Seven, Bhutan

Abstract

Biological corridors with a healthy prey base support predator dispersal, yet studies that combine occupancy and connectivity remain limited.  This study evaluates six ungulate prey species in Biological Corridor Seven, Bhutan. Thirty-one paired camera traps deployed on a 3 × 3 km grid from January to July 2025 yielded 5,144 trap days and 822 independent events. A hierarchical Bayesian multi-species occupancy model was fitted in PyMC (v5) to estimate occupancy (ψ) and detection probability (p) across winter, spring and summer. Predicted occupancy was mapped to a 500 × 500 m grid (1,689 cells) and analysed with random-walk connectivity (gdistance, R) to identify movement routes and pinch points. Generalists showed high and widespread occupancy (ψ = 0.933–0.981), with peak detectability in winter (p = 0.185–0.320). In contrast, specialists were concentrated in narrow upper-elevation areas (ψ = 0.639–0.877), peaking in spring (p = 0.085–0.164). Connectivity analysis isolated seven macro pinch points and numerous conflict segments (< 500 m long) where linear infrastructure is likely to restrict movement. Priority mitigation includes vegetated overpasses on dry slopes and bridge-style underpasses or culverts at riparian conflicts. A tiger Panthera tigris recorded at two locations confirms the use of corridor by apex predator. This integrated occupancy–connectivity framework provides a reproducible basis for prioritising mitigation and guiding adaptive corridor management under growing infrastructure development and climate pressure.