United States Department of Transportation
i
Ecology of Virginia big-eared bats in North Carolina and Tennessee.
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2016-08-24
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[PDF-10.72 MB]
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Alternative Title:Appendices to accompany report ecology of Virginia big-eared bats in North Carolina and Tennessee.
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Edition:Final report
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Abstract:The researchers conducted a study of the springtime ecology of an isolated North Carolina-Tennessee population of the Virginia big-eared bat (Corynorhinus townsendii virginianus), a federally endangered species. With limited data on the whereabouts of this population during the maternity season, the researchers could not adequately predict the impacts of transportation improvement projects (TIPs) such as the proposed widening of NC 105 (R-2566), which is ~3.3 km from the population's hibernacula on Grandfather Mountain, NC. The three objectives of the study were: 1) document seasonal movements and assess foraging habitat selection, 2) locate and describe springtime roosts and assess landscape-scale selection of roosting habitat, and 3) describe winter bat activity at the population's main hibernaculum. The researchers radio-tagged 44 adult bats (42 female, 2 male), located 35 roost sites (25 rock and 10 building roosts), and delineated foraging home range polygons for 10 bats. The researchers found the first known maternity roost sites for this species in NC, including a primary maternity roost on private land 14.4 km north-northwest from the hibernacula (≥ 359 bats used this roost), and the researchers found the first known roosts for Tennessee. Bats moved across NC 105, NC 194, and other roads while commuting the short distance to the primary maternity roost, but generally did not cross major roads during nighttime foraging bouts. Bats moved relatively short distances between the hibernacula and springtime roost sites (0.1-24.1 km), but covered a relatively large area while foraging (~330 ha on average) mainly over forested lands. Most bats used a primary maternity roost and ≥ 1 secondary roosts; primary roosts were larger, with cooler and more stable temperatures. The researchers detected winter bat activity at the hibernaculum, even on very cold days, and suggest further surveys to monitor the hibernating population. It is essential that the NC population of Virginia big-eared bats is able to cross NC 105 and NC 194 as they commute between their winter and summer habitats, but the researchers do not have sufficient data to adequately predict how Virginia big-eared bats will respond to widening or increased traffic. Widening NC 105 could have a negative effect on this Virginia big-eared bat population if these bats are vulnerable to collisions or the barrier effect of a larger road, or if road development and associated projects degrades the foraging and roosting habitats of this population. The researchers make recommendations for potential approaches to R-2566 that might minimize impacts to Virginia big-eared bats, as well as suggestions for future research that could lead to the development of safer crossing points over roads for this and other bat species.
This report's appendices are included with the report as a separate file.
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