Geographic origins and population genetics of bats killed at wind‐energy facilities

Abstract

An unanticipated impact of wind-energy development has been large-scale mortality of insectivorous bats. In eastern North America, where mortality rates are among the highest in the world, the hoary bat (Lasiurus cinereus) and the eastern red bat (L. borealis) comprise the majority of turbine-associated bat mortality. Both species are migratory tree bats with widespread distributions; however, little is known regarding the geographic origins of bats killed at wind-energy facilities or the diversity and population structure of affected species. We addressed these unknowns by measuring stable hydrogen isotope ratios (δ H) and conducting population genetic analyses of bats killed at wind-energy facilities in the central Appalachian Mountains (USA) to determine the summering origins, effective size, structure, and temporal stability of populations. Our results indicate that ~1% of hoary bat mortalities and ~57% of red bat mortalities derive from non-local sources, with no relationship between the proportion of non-local bats and sex, location of mortality, or month of mortality. Additionally, our data indicate that hoary bats in our sample consist of an unstructured population with a small effective size (N ) and either a stable or declining history. Red bats also showed no evidence of population genetic structure, but in contrast to hoary bats, the diversity contained in our red bat samples is consistent with a much larger N that reflects a demographic expansion after a bottleneck. These results suggest that the impacts of mortality associated with intensive wind-energy development may affect bat species dissimilarly, with red bats potentially better able to absorb sustained mortality than hoary bats because of their larger N . Our results provide important baseline data and also illustrate the utility of stable isotopes and population genetics for monitoring bat populations affected by wind-energy development.

Variability and repeatability of noctule bat migration in Central Europe: evidence for partial and differential migration

“…Thus, it is impossible to infer the catchment area and the level of partial migration over a larger geographical range for North American bats. However, based on isotopic data, it is apparent that both North American and European bats engage in continental-wide migration (this study [39,41,42]).…”

Carcass age and searcher identity affect morphological assessment of sex of bats

“…Hundreds of thousands of tree-roosting bats are killed annually at renewable-energy facilities (Kunz et al 2007, Hayes 2013. These species are largely solitary and difficult to observe (Shump and Shump 1982a, b) and thus such carcasses provide an important resource for scientific study (Pylant et al 2014(Pylant et al , 2016Sovic et al 2016), including for assessment of sex ratios (Korstian et al 2013). For example, there is sex morph -based evidence of more fatalities of adult male than female tree-roosting bats at some wind-energy facilities in North America (Arnett et al 2008), and one hypothesis for these uneven sex ratios is that they result from lekking behavior in which males congregate during the mating period (Cryan 2008, Cryan et al 2012.…”

Golden Eagle fatalities and the continental‐scale consequences of local wind‐energy generation

“…; Pylant et al. ), no previous studies link the spatial scale of renewable energy‐associated fatalities to their actual demographic consequences. Our results with Golden Eagles imply that these other species may be well served by evaluation of local demography and of the potential continental‐scale impacts of fatalities they encounter.…”