Summer Bat Habitat Use and Forest Characteristics in Managed Northeastern Forests

There has been limited research investigating summer habitat use of bats in managed forests in the northeastern United States. Consequently, there is limited knowledge to inform forest managers seeking to maintain or enhance bat habitat, particularly for several federally threatened, endangered, or candidate species. In summer 2017–2018, we conducted repeated acoustic surveys to determine what forest characteristics are associated with bat habitat use in managed forests in the Adirondack region of upstate New York. We modeled detection corrected probability of occupancy for bats in three phonic groups: high, mid, and low frequency. Across all phonic groups, probability of occupancy increased with decreasing canopy cover. High-, mid-, and low-frequency bats were more likely to use recently harvested sites (<10 years since harvest). High-frequency bats also used mature stands. Midfrequency bats demonstrated a preference for further distances from forest roads, whereas low-frequency bats preferred areas with a higher percentage of clutter. Our results suggest that tending and regenerating even-aged forest management practices can provide habitat for foraging bats in the Adirondacks. Study Implications: Several northeastern bat species have been granted or are candidates for federal endangered or threatened status; therefore, forest managers may increasingly need to consider how forest management actions affect bats. This research elucidates the effects of forest management practices on summer bat habitat use in northeastern forests. Foresters can use this information to limit negative impacts to bat habitat from management actions and identify management opportunities that protect or enhance bat habitat. All bat species we studied showed higher probability of use in stands with lower percent canopy cover, including stands recently harvested with the shelterwood method. However, special attention is owed to postharvest management to maintain suitable conditions, particularly concerning American beech. It is common in northeastern forests for beech to sprout root suckers following harvesting activities that can result in dense thickets, impeding bat flight abilities and limiting habitat connectivity for bats and other wildlife. Our findings also show that several bat species forage in mature stands that have a natural open understory and in areas around or near waterbodies. Consequently, even-aged tending and regeneration techniques in hardwood and mixed-wood forests, coupled with maintenance of nearby aquatic habitats, can provide habitat for bats.