Testing responses to forest edges: the example of black-tailed deer

Variations in deer response to edge habitat have been attributed to three sources: (1) differences in habitat mosaics among study areas, (2) inconsistent definition of habitat deemed available to a deer, and (3) differences in edge characteristics. The potential influences of these factors were evaluated using data for black-tailed deer (Odocoileus hemionus columbianus) collected on Vancouver Island, B.C. Edges were defined among clear-cut, second-growth, and old-growth habitats. Deer distributions and movements were determined using radiotelemetry. Little response of deer to edges was detectable where habitat was a fine-grained mosaic of forage and cover areas. Where forage and cover occurred in clearly distinct habitats, responses to edge were apparent. Techniques defining area available to wildlife in use–availability analyses differ among studies. We found that the impact of changing the area considered to be available mattered little when habitats were finely interspersed. We could not unequivocally separate effects of differences in habitat mosaics from effects of differences in vegetative characteristics of edge habitat, but results were consistent with other findings that edges are less important when forage and cover are interspersed. We discuss the implications of our findings for the interpretation of research results.