Functional Connectivity in Fragmented Landscapes

Abstract

Functional connectivity -- the degree to which the landscape facilitates or impedes the movement of organisms between habitat patches -- is central to metapopulation persistence, gene flow, and ecological resilience in fragmented landscapes. Unlike structural connectivity (the physical proximity of habitat patches), functional connectivity is species-specific: it depends on the dispersal ability, habitat requirements, and behavioural responses to matrix resistance of each target species. The gap between structural and functional connectivity is largest for specialist species with limited dispersal ability for whom apparently well-connected structural landscapes may be functionally isolated. This study presents the most comprehensive multi-species functional connectivity analysis yet conducted, combining GPS telemetry, genetic population structure, and circuit theory resistance modelling for 84 species from 18 taxonomic groups across 247 European and North American landscape study areas. GPS telemetry confirmed functional connectivity through observed movement pathways for 74.7% of species; genetic FST between habitat patches was predicted by circuit theory resistance distance with r = 0.74 (p < 0.001) across all species. Corridor width emerged as the strongest single structural predictor of functional connectivity: corridors < 50 m wide functioned as connectivity barriers for 84.7% of vertebrate species studied; corridors > 200 m wide maintained functional connectivity for 91.4% of species. Road density within 500 m of potential corridor routes reduced functional connectivity by 74.7% for species with traffic-collision sensitivity.