Forest characteristics predict Tri-colored Bat (Perimyotis subflavus) activity within novel Colorado habitats

Abstract

Several studies have indicated that tri-colored bats (Perimyotis subflavus) are extending their distributional range westward in the United States. Montane and subalpine habitats consist of a mosaic of forest types including Lodgepole Pine woodlands and meadows, which provide an opportunity to study how a newly arriving species—typically associated with lowland riparian systems—is adapting to novel environmental conditions. The objectives of this study are to document Tri-colored Bat activity in these novel habitats and to quantify which factors are influencing activity patterns in habitats and at elevations not previously documented. We surveyed sites in various stages of secondary succession following beetle kill outbreaks using acoustic monitoring and nonparametric multiplicative regression to model habitat activity patterns. Results showed that activity was highest in meadows and early time-since-kill (TSK) forests in the beginning of the survey period and activity increased in late TSK forest habitats at the end of the survey in early August. Tri-colored bats are not restricting their activity to lower-elevational riparian areas in the Colorado foothills but appear to also be using these high-elevation habitats. Careful consideration of misidentification confirms the high likelihood of tri-colored bats at our sites. We hope that this study will support conservation efforts considering the expected US Fish and Wildlife Service Endangered listing for this species.