HABITAT USE BY BATS IN TWO INDIANA FORESTS PRIOR TO
SILVICULTURAL TREATMENTS FOR OAK REGENERATION
Jeremy J. Sheets, Joseph E. Duchamp, Megan K. Caylor, Laura D’Acunto, John O. Whitaker, Jr.,
Virgil Brack, Jr., and Dale W. Sparks1
Abstract.—As part of a study examining the effects of silvicultural treatments for oak regeneration on habitat use by bats, we surveyed forest stands prior to the implementation of treatments in two state forests in Indiana. Interior forest sites corresponding to areas designated for silvicultural treatments were surveyed for 2 nights each during the summers of 2007 and 2008. Additionally, three types of existing forest openings (pre-existing harvest openings, forest edges, and open corridors) were surveyed during 2007 in the same area. We assessed bat habitat use by recording echolocation calls using ANABAT II bat detectors. We characterized a location as experiencing high levels of activity, experiencing low levels of activity, or being unused by a species of bat based on recorded call minutes. We used occupancy models to account for differences in detection probability.
Stands designated for uneven-aged harvest had a greater probability of experiencing high activity by a species of bat when compared to areas designated for other silvicultural treatments. Existing forest openings had probabilities of high activity levels that were similar to each other, but high activity levels in these habitats were less likely for Indiana myotis (Myotis sodalis) and northern myotis (M. septentrionalis) when compared to forest interior locations. At interior forest sites, northern myotis were more likely than other species to have high activity levels. These results provide some insight into the potential responses of bats to forest management practices and serve as a baseline for future experimental treatments.