Habitat Selection by Bats in Fragmented and Unfragmented Aspen Mixedwood Stands of Different Ages

To determine if bats prefer certain ages of aspen mixedwood forest for roosting and foraging, and to predict the impacts of logging on bats, we compared the relative abundances and foraging activities of bats in young, mature, and old stands in  and , using bat detectors. In , we also assessed post-logging bat abundances in two of the mature and two of the old stands. We tracked radio-tagged Myotis lucifugus and Lasionycteris noctivagans to roost trees, which we measured and compared to a random sample of wildlife trees. Mean total activity of all bats was significantly greater in old than in young or mature stands. It also appeared greater in unfragmented than fragmented stands, but not significantly so. All  roost trees were in old forests. Bats preferred tall (mean: . m), newly dead Populus spp. with heart rot and low leaf cover (mean: %). Tree-roosting colonies were small (– bats) and transient. Bats likely select trees large enough to house colonies and provide suitable temperatures, and these trees are only available in old stands. Roost preference likely explains observed activity patterns. To sustain bat populations in these forests, old stands must be retained and roost sites preserved by managing the forest at the stand level.