Distribution and Habitat Association of the Northern Long-eared Bat

Because of white-nose syndrome, the northern long-eared bat (Myotis septentrionalis) is experiencing rapid population declines across the majority of its range. This decline has prompted increased regulatory protection and thus an increased need for effective habitat management strategies. Insight into the species habitat associations, however, is a prior necessity to ensure management practices are biologically relevant. Understanding these relationships requires a holistic approach that addresses the multiple ways in which the species is interacting with its environment. The objective of my thesis was to address these relationships following a multi-scale approach that assessed the factors associated with roost tree selection, distribution, and habitat use. I conducted a quantitative meta-analysis of all northern long-eared bat roost-selection studies, thus enabling inference across the range of the species. Secondly, I sought to understand the factors associated with the northern long-eared distribution in Nebraska by conducting a multiscale occupancy study with four acoustic survey stations nested within 101 10 km x 10 km grids distributed across Nebraska. Lastly, to assess factors associated with multi-scale occupancy at finer spatial scales, I combined presence/absence results from 5 intensively sampled study sites in Nebraska with on-the-ground habitat measurements. Results from the meta-analysis indicate selected roost trees had a greater amount of bark remaining on the bole, a larger diameter at breast height, a lower decay class, and were taller. Results from the statewide occupancy study provide evidence for relationships between large-scale occupancy (ψ) and forest clumpiness, proximity to potential hibernacula, and summer temperature. Within occupied grids, evidence supported a positive relationship between small-scale occupancy (θ) and forest area within 125 m. Results failed to provide evidence of habitat factors associated with ψ at the 5 study sites likely due to high presence of the species. Evidence, however, did support a positive relationship between canopy closure and θ. Reported occupancy estimates between the two studies results serve as a pre-white-nose syndrome baseline, as I collected all data prior to the detection of white-nose syndrome in Nebraska. Advisor: Craig R. Alle