Landscape-scale drivers of bat acoustic activity in the interior mid-Atlantic

We assessed the landscape scale foraging habitat associations from a multi-year perspective using generalized linear mixed models for nine bat species using bat detectors in the interior mid-Atlantic region of Maryland and Pennsylvania, United States. The landscape use trends we detected included greater Eptesicus fuscus acoustic activity along field edges than in forested habitats, and greater Lasiurus borealis acoustic activity in xeric conditions rather than hydric/mesic conditions relative to aspect. Additionally, no bat species had a meaningful relationship with McNab’s Landform Index, atypical for Myotis septentrionalis. Our results also demonstrate that most bat species’ acoustic activity were stable over years though some counts were extremely low, attributable in part to population reductions from white-nose syndrome. We also observed variation of bat activity on the landscape throughout the active season. Eptesicus fuscus, M. lucifugus, M. septentrionalis, M. sodalis, and Perimyotis subflavus acoustic activity levels over the active season appear to be related to the annual reproductive cycle, i.e., pregnancy, lactation, and volancy of pups. Our study is indicative that bat acoustic activity can vary between regions and years, highlighting the need for more multi-year, locally focused research of bats.