Wind turbines and wind farms can cause problems for bats. The pressure differences that build up as the blades turn can implode the inner organs and lungs of bats. This damage is called ”barrotraumas”. now a German study has shown that the bats killed by the turbines come from long distances away.
The study was undertaken by the Leibniz Institute for Zoo and Wildlife Research (IZW) and they found out that many of the bats killed by wind farms in Germany had originated in the Baltic States. With over 200,000 bats a year killed by German wind farms there are fears that the losses are not sustainable.
Bat populations may need a long time to recover from any additional losses owing to fatalities at wind turbines if they recover at all.
The researchers discovered the origins of the killed bats by looking at hydrogen isotopes in fur keratin. Small differences in ratios allowed the team to discover the home locations of the bats.
Majority of bats killed at German wind farms come from Baltic states.
Many bat species in Europe will migrate at spring and Autumn. The study found that almost all Nathusius pipistrelles killed in Germany had come from the Baltic countries, Belarus and Russia.
The study also discovered that the majority of greater noctule bats and Leisler’s bats killed by German wind turbines came from northeastern Europe, probably from Scandinavia, Poland and the Baltic countries.
It was only the small common pipistrelles where local populations made up the majority of kills.
“Bats have a very low reproductive output, with only one or two offspring per year,” says Christian Voigt from the IZW. “Bat populations may need a long time to recover from any additional losses owing to fatalities at wind turbines if they recover at all.”
New wind farms are close to forest areas increasing risks for bats.
The biggest concern for conservationists is that the numbers of bats now being killed by wind turbines is increasing. This is mainly due the siting of new wind farms. As many people object to the seeing wind turbines many of the newer farms are being placed close to forests so that the trees can help shield the view.
Putting the wind farms close to forest means that they are coming into close contact with bats as the bats fly along the treeline as they forage for food.
As countries commit to greater levels of renewable energy and wind energy thee is the risk that the new turbines could impact on even remotely located ecosystems.
As bats provide an essential service by controlling numbers of pests and insects there is the risk that if current rates of deaths continue to increase then this ecosystem service could be lost.
International co-operation needed to protect bats.
Voigt is calling for the EU and other affected countries to work together to develop a large geographical scale plan in order to protect and conserve bat numbers.
Voigt argues “We need an intelligent change in our energy policy, where we minimise the negative consequences for both people and wildlife.“
With the highest risks to bats in Germany occurring at dusk during the Autumn migration period Voigt suggests that turning off the most high-risk wind turbines for just an hour or two could have a major benefit to bat survival.