Landscape and anthropogenic effects on mammal occupancy in the Appalachian Trail corridor

摘要

Anthropogenic and landscape effects on wildlife are typically assessed at the local or patch level, but such effects are often difficult to extrapolate to larger spatial extents. Studies that examine broad-extent effects of anthropogenic disturbances, fragmentation and habitat loss on mammal occupancy are uncommon and yet much-needed. Macro-level occupancy studies are one way to assess anthropogenic and landscape factors that vary and interact over different geographic extents. Here we assess anthropogenic and landscape effects on occupancy and distribution for several mammal species within the Appalachian Trail (AT), a forest corridor that extends across a broad section of the eastern United States. Utilizing camera traps and a large volunteer network of citizen scientists, we were able to sample 447 sites along a 1024 km section of the AT. To assess anthropogenic influences on mammal occupancy we investigated the effects of available habitat, hunting, recreation, and roads on eight mammal species. Landscape effects were measured by investigating the influence of available habitat, patch area, isolation, edge and connectivity on five carnivore species. Occupancy modeling revealed that available habitat was among the top predictors of occupancy for nearly all mammal species. Anthropogenic effects were well represented in the top models, with hunting being the strongest predictor of mammal occupancy. Landscape configuration metrics (patch area, isolation, edge, and connectivity) were not well represented in the top models. The total amount of edge was the only landscape metric to influence the occurrence of three carnivore species: bear, coyote, and raccoon. Our study highlights the importance of forest cover to mammal species, regardless of configuration within the landscape or the anthropogenic disturbances in the AT corridor. This study also stresses the importance of compounding direct and indirect anthropogenic influences operating at the regional level. Scientists and managers should consider these impacts and their potential combined influence on wildlife persistence when assessing optimal habitat or considering management actions.