Northern long-eared bat (Myotis septentrionalis) populations have declined sharply in recent years due to the introduction and rapid spread of White-nose Syndrome. This has prompted an urgent need for a greater understanding of their natural history in order to support the conservation of extant populations, particularly where forested day-roost and foraging habitats are being fragmented by development. Prior to 2006, with other Myotis species on the endangered species list, northern long-eared bats were understudied. In recent years, with the pressing concern to document the ecology of all cave bats affected by White-nose Syndrome on the landscape, researchers have now prioritized northern long-eared bat habitat needs, day-roost use, social dynamics, and barriers to gene flow. A relatively new discovery has been the numerous coastal populations that occur in smaller forest patches often surrounded by anthropogenic development. The goal of my research is to aid in informing future monitoring and management protocols that are specific to northern long-eared bats, particularly as they may shift from Threatened to Endangered under the Endangered Species Act. The chapters of this dissertation explore (1) similarities and differences between coastal and more documented upland habitat associations for populations of northern long-eared bats throughout the summer months through the use of acoustic detectors; (2) relationships between acoustic activity patterns and weather on an hourly basis for several bat species on Long Island, New York; and (3–4) day-roost characteristics and social network dynamics of a coastal northern long-eared bat maternity colony on Long Island, New York. I found that northern long-eared bat colonies have larger spatial footprints in – and a moderate tolerance for – forests in anthropogenically-developed areas than previously believed, though many natural history aspects of the bat were similar among coastal and interior populations. Installation of artificial day-roost structures such as bat boxes would likely be used and highly beneficial to colonies in these conditions, particularly to offset the deleterious effects of stochastic disturbance events on day-roost availability and to support social cohesion (and, by extension, reproductive success) for coastal maternity colonies. Additionally, I found that acoustic activity increased in riparian areas, or at sites closer to water features, and as proportion of forest coverage increased at a broad scale. However, immediately around the detector this relationship was reversed. Taken together, this demonstrates that riparian corridors, water features, and forest structural heterogeneity should explicitly be included in management guidelines. / Doctor of Philosophy / White-nose Syndrome is a fungal disease that has killed millions of cave bats in North America, including the northern long-eared bat (Myotis septentrionalis) that during the spring through fall uses forests for roosting and foraging habitat. As the disease continues to spread, and as forests are increasingly being lost to urbanization, it is imperative for researchers and land managers to understand the landscape needs of this species so that they can retain those forests that are used by this species. In addition to broader landscape needs, it is important to understand what specific forest stand to tree features the bats are using, how their social dynamics support their reproductive success, and how to best support habitat conditions foster mating in the fall swarm to avoid inbreeding. In recent years, more northern long-eared bats have been documented in coastal landscapes, suggesting that these areas might be more important to the conservation of the species than previously believed. In this dissertation, my aim was to explore how or why the landscapes in these coastal areas were being used by these bats both during nightly foraging and during the day as resting areas (day-roosts). Additionally, I explored how multiple species of bats were responding to weather conditions on the coast across seasons. Overall, I found that complex forests continue to be an important resource for northern long-eared bats, as well as water features whereby the latter should be more explicitly included in conservation management plans. Northern long-eared bats also show an ability to successfully use small forest patches within a larger urbanized landscape, including using human structures for day-roosts. Human structures might provide reliable, multi-year day-roosts in areas where extreme coastal weather events (hurricanes) occur or increase or as natural processes reduce the suitability of these forests to provide day-roosts. These structures, particularly artificial roost boxes could also support the social network of reproductive northern long-eared bats and thus maintain population stability to some extent.

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The endangered northern long-eared bat (<i>Myotis septentrionalis</i>) has experienced severe population declines since the 2007 introduction of <i>Pseudogymnoascus destructans</i>, the fungal pathogen that causes white-nose syndrome (WNS). Due to continued mortality, failed recruitment, and range fragmentation, effective species conservation would benefit from local and regional research related to habitat selection and suitability, seasonal activity, and large-scale estimates of continued occupancy across the post-WNS landscape. In this dissertation, I explored maternity colony home range size and habitat selection, both coastal and interior seasonal activity patterns, habitat suitability, and species occupancy trends in the Mid-Atlantic and Northeastern United States. Research from the Coastal Plain of North Carolina, based on diurnal roost locations, revealed that core and peripheral home range estimates were large but comparable to areas of contiguous forest cover in other regions of the species' range. Prior to juvenile volancy, female northern long-eared bats selected red maple (<i>Acer rubrum</i>), water ash (<i>Fraxinus caroliniana</i>), and loblolly pine (<i>Pinus taeda</i>) as day-roosts, but then used sweetgum (<i>Liquidambar styraciflua</i>), swamp bay (<i>Persea palustris</i>), and water tupelo (<i>Nyssa aquatica</i>) after juvenile volancy. At the second-order spatial scale (i.e., home range within a region), roosting home ranges were associated with woody wetlands farther from anthropogenic development and open water. However, within the third-order scale (i.e., core home range within a periphery), northern long-eared bats selected woody wetlands adjacent to intact upland forests, areas containing shorter trees and occurring proximal to open water. Research utilizing passive acoustic monitoring on the Coastal Plain of both Virginia and North Carolina found that northern long-eared bat relative activity was highest in areas containing greater proportions of woody wetlands and upland pine-dominated evergreen forests. Conversely, the likelihood to record northern long-eared bats was associated with smaller proportions of woody wetlands and open water resources, emphasizing the importance of upland forests adjacent to these features. I also observed a higher probability of recording northern long-eared bats during non-winter seasons and when temperatures were between 10 and 25 °C, potentially highlighting an optimal thermoneutral zone for the species regionally. Research using presence data from the Monongahela National Forest (MNF) in the Central Appalachians of West Virginia found that northern long-eared bat habitat, whether occupied or not, was abundant (43.1% of the MNF) and widely dispersed. Northern long-eared bat habitat on the MNF was often characterized as mature, interior mixed mesophytic forests. Research using passive acoustic surveys associated with hibernacula in western Virginia found that northern long-eared bats were most active near hibernacula during warmer weeks of the fall swarm and spring emergence, when rainfall was low. Similarly, the probability of northern long-eared bat activity was highest near hibernacula during the spring/summer season. However, unlike relative activity, the likelihood of recording northern long-eared bats was associated with more heterogeneous, interior forests. Finally, research using a combination of long-term repeated and single-season clearance survey data from New England found that northern long-eared bat occupancy was highest on steep hillsides in contiguous forested landscapes with minimal anthropogenic development. My results also indicated higher occupancy of northern long-eared bats in warmer regions, particularly along the New England coastline and offshore islands. These findings collectively stress the importance of managing areas of large core forest to promote sustainable roost formation and productive foraging areas, often associated with dynamic ecotones, to support the survival and recovery of northern long-eared bats in the post-WNS Mid-Atlantic and Northeast. / Doctor of Philosophy / The northern long-eared bat was once one of the most common bat species in North America. However, due to population impacts caused by white-nose syndrome (WNS) the species is now recognized as endangered by the United States Fish and Wildlife Service. In this dissertation, I explore habitat selection and suitability, seasonal activity, and occupancy trends of remnant populations of northern long-eared bats in the Mid-Atlantic and Northeast of the United States, representing approximately 25% of the species' historical range. Specifically, I examined home range size and habitat selection of a reproductively successful maternity colony on the Mid-Atlantic Coastal Plain, overwintering activity at both interior and coastal sites, habitat suitability in the Central Appalachians, and spatial occupancy trends across New England. My research found that reproductive northern long-eared bats actively selected for specific cover features and displayed notable shifts in roost tree selection throughout the maternity season on the Coastal Plain of North Carolina. My research also indicated that northern long-eared bats were more active during non-winter seasons, favoring moderate temperatures and areas of forested wetlands adjacent to evergreen forests in coastal North Carolina and Virginia. In Virginia, northern long-eared bat activity near mountain hibernacula was highest in areas of greater landscape richness prior to and after hibernation. Finally, my research from New England found that northern long-eared bat occupancy was highest in steeper, forested landscapes in the absence of human development. Overall, this research highlights the need to conserve and manage forest ecosystems to promote recovery of the endangered northern long-eared bat. Conservation and management efforts informed by population status, activity trends, and habitat associations will be invaluable in guiding species recovery efforts.