The Distribution and Habitat Use of North Dakota Bats

Abstract

Prior to 2009, a comprehensive statewide survey of occurrence and distribution of bats in North Dakota had not been conducted. From 2009 to 2012, mist netting, radio telemetry, and acoustic monitoring were conducted to document species presence and habitat associations across North Dakota. We surveyed multiple sites at 17 locations, captured a total of 309 bats, documented habitat associations, and identified roosting sites. Data was then used to: 1) build habitat suitability maps (also called species distribution maps or SDMs) for each species in the state, 2) examine the environmental and climatic variables that influence bat habitat use along the periphery of their distribution, 3) assess the effect of sampling technique on habitat suitability models, and 4) determine if North Dakota's badlands region contains overwintering bat populations that may be susceptible to white nose syndrome, an emerging fungal disease of hibernating bats. We confirmed the presence of 11 species in the state and found that five species were present in areas outside their ND IUCN distribution. Maximum-entropy modeling showed that temperature was the most important variable for SDM production. We found that sampling technique (physical capture vs. acoustic detection) led to pronounced differences in habitat suitability maps for some species (33.9% overlap; Myotis septentrionalis) while models from other species were highly similar (80.4% overlap; Myotis lucifugus). Our findings show that acoustic detection results in better SDMs for Myotis spp. while physical capture was best for Eptesicus fuscus and Lasionycteris noctivagans. During the winter, we positively identified four species based on both acoustic detection and physical capture: E. fuscus, Myotis evotis, Myotis ciliolabrum, and Corynorhinus townsendii. Based on known and potential hibernacula locations, we produced a habitat suitability map that was successfully used to locate additional potential hibernacula. We also recorded temperature in confirmed and potential hibernacula, finding that temperatures were within the optimum range of fungal growth. The information gathered from these studies will be used to develop the first statewide conservation action plan for North Dakota bats. Also, the habitat suitability maps produced will be used by managers to target areas of high priority for conservation of bat communities.