Although wind turbines are essential in wind energy development, the massive-vaned device has been linked to the widespread mortality of bats, particularly in the Appalachian Mountains.

Scientists know which bat species are being killed, but little is known about how the animals are moving across the area, the number of their population, and what their genetic diversity is.

Now, a new study conducted by the University of Maryland Center for Environmental Science has tracked down the origins of the dead bats using chemical fingerprints.

The highest bat mortality rates all over the world have been recorded at the wind energy sites along the Appalachian Mountains. Two of the species that comprise the majority of turbine-related deaths in North America are the eastern red bat (Lasiurus borealis) and the hoary bat (Lasiurus cinereus).

Associate Professor David Nelson, co-author of the study, said their research aims to help conservationists understand: are these the species we should be concerned about?

Examining The Chemical Fingerprint

Nelson and his colleagues used a combination of genetic analysis and stable isotope for the first time to evaluate the impacts of wind energy development on bats in the Appalachian region.

The research team used stable hydrogen isotopes - some kind of chemical fingerprint - to reveal where the bats have been despite having flown long distances.

Various forms of hydrogen exist in water depending on where it falls. Rain from higher elevations has a different signature than rain from lower elevations, and the differences are recorded in the hair of each bat.

Scientists can then analyze the bat hair and use the hydrogen isotope signature to find out where the animals spent their summer, which is a time when these animals molt and grow in new fur.

The team also extracted DNA from the bats' wing tissue to examine their genes. This will help experts understand how capable the species are to adapt to an increase of deaths in their population.

How Wind Energy Development Affects Bat Populations

Researchers found that half of the eastern red bats that were killed were not local residents, and may have spent their summer at places far from the wind turbines.

In contrast, almost all of the hoary bats spent their summer in the Appalachian region.

The eastern red bats represented one massive population, while the hoary bats represented a small group of bats.

The team's findings suggest that intensive wind energy development affects bat populations differently. The larger populations of red bats are potentially more able to cope with wind turbine-associated deaths than the relatively smaller population of hoary bats.

Cortney Pylant, the lead author of the new research, said it is often difficult to understand the impact of turbine-related deaths among bats because of the lack of data.

"Studies such as this can help to identify species and populations at particular risk," added Pylant.

The study is featured in the journal Ecological Applications.

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