Macrohabitat factors affect day roost selection by eastern red bats and eastern pipistrelles in the southern Appalachian Mountains, USA

Abstract

Although roost sites are critically important to bats, we have few data on macrohabitat factors that affect roost selection by foliage-roosting bats. Such data are needed so that forest managers can make informed decisions regarding conservation of bat roosts. Our objective was to examine roost selection by non-reproductive eastern pipistrelles ( Perimyotis subflavus) and red bats ( Lasiurus borealis) in a dense deciduous forest undergoing low-intensity timber management in the southern Appalachian Mountains of western North Carolina, USA. During May to August 2004–2006, we radiotracked eight red bats and seven pipistrelles to roosts for 1–14 days (red bats, x ¯ = 4.11 days, n = 19 roosts; pipistrelles, x ¯ = 7 days, n = 15 roosts). We compared roost and random trees or points using paired-sample t-tests for tree and microhabitat characters and logistic regression models of one to three variables for macrohabitat characters. Neither red bats nor pipistrelles selected roosts based on tree or microhabitat characteristics. Red bats used a wide range of stand ages and conditions and, based on our most plausible models for macrohabitat variables, roosted closer than expected ( x ¯ = 70.6 m ) to linear openings such as gated roads. Pipistrelles only used stands ≥72 years in age and roosted closer than expected ( x ¯ = 185.6 m ) to non-linear openings and at elevations lower than expected ( x ¯ = 882 m ) . Combined evidence of multiple variables indicated that pipistrelles preferred to roost close to streams. Our results indicate that land managers in the southern Appalachians should maintain a diversity of age classes to provide roosting habitat for both species, and that pipistrelles in particular may benefit from retention of mature stands or buffer zones near perennial streams. Furthermore, non-reproductive red bats and pipistrelles may prefer to roost near openings to minimize commuting costs when openings comprise a small proportion of a densely forested landscape.