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Cincinnati, OH, United States

Zurcher A.A.,Indiana State University | Sparks D.W.,Environmental Solutions and Innovations Inc. | Bennett V.J.,Purdue University
Acta Chiropterologica

Roadways are nearly ubiquitous parts of the modern landscape, but their impact on bats remain relatively unknown. We studied the influence of vehicular traffic on the behaviour of commuting bats near the Indianapolis International Airport. A previous study at this site documented that Indiana bats (Myotis sodalis) were much more likely to cross roads with low traffic volumes. One potential interpretation of this result is that bats perceive motor vehicles as a threat and exhibit avoidance behaviour whether or not the bats are in immediate danger. To test this hypothesis, we observed 211 cases of bats approaching roads that bisected their commuting routes. Information recorded at the time included the presence or absence of vehicles, the height the bat was flying, whether a bat reversed course prior to crossing the road and if so the distance from the road or vehicle (if present) when it altered its direction, and finally the speed, type and relative level of noise emitted by vehicles. Results revealed that bats were more than twice as likely to reverse course when vehicles were present as opposed to their absence. When automobiles were present 60% of bats exhibited avoidance behaviour, reversing course at an average of 10 m from a vehicle. Conversely, when no automobiles were present, only 32% of bats reversed their course and 68% crossed the road. The height a bat flew, speed of the vehicle, type of vehicle or level of noise emitted by vehicles had no effect on the likelihood of bats reversing course. These data support the hypothesis that bats perceive vehicles as a threat and display anti-predator avoidance behaviour in response to their presence. © Museum and Institute of Zoology PAS. Source

Meretsky V.J.,Indiana University Bloomington | Brack Jr. V.,Environmental Solutions and Innovations Inc. | Carter T.C.,Ball State University | Currie R.R.,U.S. Fish and Wildlife Service | And 7 more authors.
Journal of Wildlife Management

The size and distribution of measurement errors associated with major techniques for estimating numbers of hibernating bats are unstudied, although this is the principle method of enumerating several endangered bat species. However, decisions concerning the listing status of a species under the Endangered Species Act require consistent and accurate estimation of population size and trends. Recent advances in digital photography have improved the ability to produce a quantitative record of the numbers of bats in hibernacula. We surveyed clusters of Indiana bats in a hibernaculum and compared results from counts of digital photographs of clusters to results from 4 variations of visual estimation. We counted bats in photographs using Geographic Information System digitization over the photograph. Total counts from 2 sets of photographs varied by <1.5%. Nonphotographic estimation techniques varied from 76% to 142% of counts from photographs for clusters for which estimation (rather than counting) was used. Where feasible, photography can improve status and trend information for species of concern, permitting more timely and specific management actions. © 2010 The Wildlife Society. Source

Duchamp J.E.,Purdue University | Duchamp J.E.,Indiana University of Pennsylvania | Sparks D.W.,Indiana State University | Sparks D.W.,Environmental Solutions and Innovations Inc. | Swihart R.K.,Purdue University
Journal of Mammalogy

Temperate bat species are well-known predators of nocturnal insects; however, their role in forest nutrient cycling is unclear. We tested the "nutrient hot spot" hypothesis, which suggests that colonial bats should create nutrient peaks in and around their roosts via guano deposits. We measured the mass and nitrogen content of guano deposited outside of roosts occupied by maternal colonies of 2 tree-roosting species, Myotis septentrionalis and M. sodalis. We assessed whether these measures were related to date, species, and bat abundance using least-squares regression. We then compared the expected amount of nitrogen deposited over a maternity season to the expected annual amount of nitrogen mineralized by a forest. Mass of guano deposited increased with bat abundance and corresponded to periods of parturition and lactation. Nitrogen mineralization near a large roost of bats can be 380 of that due to decay of leaf litter. Such nutrient peaks could influence patterns of forest vegetation by impacting growth of herbaceous plants and development of tree seedlings, and the magnitude of these effects should increase in nutrient-poor areas. © 2010 American Society of Mammalogists. Source

Bennett V.J.,Texas Christian University | Sparks D.W.,Environmental Solutions and Innovations Inc. | Zollner P.A.,Purdue University
Landscape Ecology

Negative impacts of road networks on wildlife are of global concern. While direct mortality of wildlife via roads has been well-documented, we know little about indirect effects of roads. Using a simulation model parameterized from empirical data, we explored how roads in proximity to maternity roosts influenced foraging activities of the endangered Indiana bat. First, we conducted manipulated landscape simulations to identify characteristics (such as traffic volume, foraging habitat availability, etc.) that influenced landscape permeability. We used a classification and regression tree procedure to assess which landscape and road-related variables, alone or in combination, influenced bat movement. We determined that roads did act as filters (>10 vehicles/5 min) or barriers (>200 vehicles/5 min) to movement. However, it is a combination of the proportion of foraging habitat accessible without crossing a road, and roost-to-road distance that dictated whether the barrier and filter effects of roads hindered the bats' foraging abilities. We then simulated movement patterns and foraging success of Indiana bats at 32 existing maternity roosts to identify conditions under which colonies currently persist. We established a foraging success threshold, above which Indiana bats currently persist. The value represents the time virtual bats spend in foraging habitat during the simulation period. Finally, simulations from these landscapes around known maternity roosts demonstrate that the road network and landscape configuration are critical to foraging success. This modeling approach and threshold value are beneficial to road developers and represent an invaluable tool in the ecological design of transportation infrastructures. © 2013 Springer Science+Business Media Dordrecht. Source

Swecker C.D.,Marshall University | Swecker C.D.,Environmental Solutions and Innovations Inc. | Jones T.G.,Marshall University | Donahue II K.,Marshall University | And 2 more authors.
Southeastern Naturalist

Introductions of nonnative crayfish species have resulted in the global decline of native crayfish populations, including those in North America. Historically, the North American range of Orconectes limosus (Spinycheek Crayfish) extended from Maine, southward into northern Virginia, including West Virginia's eastern panhandle. A 1988-1989 survey of the eastern panhandle of West Virginia resulted in the capture of only 14 O. limosus, but an abundance of the nonnative Orconectes virilis (Virile Crayfish). These data along with additional unpublished accounts of declines of O. limosus populations prompted our survey of eastern West Virginia. In 2005 and 2006, crayfishes were collected from streams within the West Virginia range of the O. limosus, including historic capture locations. Our collection of 600 individuals comprised crayfishes from 3 species: O. virilis, Orconectes obscurus (Allegheny Crayfish), and Cambarus bartonii bartonii (Common Crayfish). The nonnative O. virilis was present at 26 of the 30 sites, whereas O. limosus was absent from all collections. Our results may indicate extirpation of some or all populations of O. limosus in eastern West Virginia, but absence data may also reflect a low detection probability of individuals from small populations. Competition between the nonnative O. virilis and O. limosus have been reported elsewhere, and likely explains the extirpation of populations of O. limosus in West Virginia. Source

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