Intra-specific effects of forest loss on the distribution of the forest-dependent northern long-eared bat ( Myotis septentrionalis)

Abstract

Forest fragmentation by the expansion of human activities is acknowledged as an important factor driving declines of forest species worldwide and quantitatively characterizing this trend is essential to understanding the response of populations of forest-dependent species. To examine the impacts of forest cover loss and changes in composition on forest-dependent bats, we examined the effects of these factors on the distribution of the northern long-eared bat ( Myotis septentrionalis) in a case study. We surveyed forest fragments in the forest-agricultural landscape of Prince Edward Island, Canada, to assess the occupancy of bats in fragments. Logistic regression and multimodel inference using Akaike’s information criteria were used to identify potentially important predictor variables influencing the distribution of the northern long-eared bat at the fragment and landscape level and quantified their effects. A compositional variable, area of deciduous stands, was found to be the best predictor of the presence of M. septentrionalis. We found the effects of fragmentation were greatest at the fragment level for females and at the landscape level for males. This case study emphasizes the importance of examining intra-specific resource selection in how it affects the response of a forest-dependent species to fragmentation.