Selection of tree roosts by male Indiana bats during the autumn swarm in the Ozark Highlands, USA

Abstract

ABSTRACTWe identified 162 roosts for 36 male Indiana bats (Myotis sodalis) across 3 study areas in the Ozarks of northern Arkansas, USA, during the autumn swarm (late Aug to late Oct, 2005 and 2006). Bats utilized 14 tree species; snags of shortleaf pine (Pinus echinata) were the most utilized (30% of roosts) and pines were selected over hardwoods. Diameter of trees and snags used for roosting ranged from 7.8 cm to 68.6 cm diameter at breast height (dbh), but bats used trees ≥20 cm dbh at a greater proportion than their availability. Roosts were located in a number of different forested cover classes, including shelterwood and group selection stands that had undergone partial harvesting. Roosts in 2 of 3 study areas showed no differences in proportional use of forest cover classes versus availability of those classes. However, in one study area, mature forests (≥50 yr old) that had been burned once recently and stands burned multiple times over the past 10 years were used at a greater proportion than their availability, whereas mature forests that were not burned were used at a lower proportion than their availability. An examination of stand age data indicated that 98% of all roosts were located in stands ≥38 years old, suggesting that this is an important age threshold for roost selection in the Ozark Mountains. Bats in 2 study areas roosted at lower slopes in the higher elevation portions of the study areas, whereas no selection for topographic aspect were observed in all 3 study areas. Our data indicate that perceived habitat selection by a species may differ within the same geographic region and these differences could be due to factors such as differing selection among individuals, differences in juxtaposition of landscape components and cover types, and differing biological components such as the distribution of predators and predator densities. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.