With regard to wildlife, green energy is not always green. Migratory birds and resident bats struggle with wind turbines that not only disrupt their normal pathways, but also cause them to die. This happens either directly by collision - or through something called barotrauma. Changes in air pressure caused by massive displacement of air from moving wind turbine blades can severely injure the inner organs of bats - and cause major damage to their complex ears, on which they depend to hear their own echolocation calls for orientation and foraging.
On the last weekend of August, bats get their own celebration: European Bat Night, an event to rise awareness on these winged mammals and their essential role for natural ecosystems and human economies.
Bats get their own day on the last weekend of August. Or rather, night: on European Bat Night, an international event promoted by UN bats secretariat Eurobats looks to get people closer to these animals. This is hoped to help the public better understand the important role of bats in the ecosystem, and encourage their conservation – since many species are in danger of extinction.
These winged mammals are a “keystone species” essential to some ecosystems, being responsible for the natural control of agricultural pests, pollination of plants and seed distribution.
Bats are critical to the survival of many wild species. Without them, the diversity of plants and animals on Earth would be greatly reduced. Even their droppings (known as guano) are a valuable natural fertilizer.
Although bats have almost no natural enemies, over past decades they have been facing numerous threats. All of these are related to human activity: habitat loss due to deforestation, changes in building style, and overhunting for bush meat are among them.
Beyond this, the ever-more more aggressive use of pesticides in agriculture has also lead to a significant decline of insects – bats’ main food source – thus poisoning bats.
And according to Andreas Streit, executive secretary of Eurobats, a new and increasing threat to bats are wind turbines that produce renewable energy.
Wind energy not bat-friendly
With regard to wildlife, green energy is not always green. Migratory birds and resident bats struggle with wind turbines that not only disrupt their normal pathways, but also cause them to die. This happens either directly by collision – or through something called barotrauma.
Changes in air pressure caused by massive displacement of air from moving wind turbine blades can severely injure the inner organs of bats – and cause major damage to their complex ears, on which they depend to hear their own echolocation calls for orientation and foraging.
This presents a bit of a paradox, considering that renewable energy is a growing alternative for fossil fuels and a clean source of energy for the future.
Germany is a wind energy pioneer, with around 24,000 wind turbines currently installed throughout the country. And each one of these cause the death of about 10 to 12 bats per year on average, depending on the geographical location and type of turbine. Annual bat deaths due to wind turbines are estimated at 250,000 per year.
Yet contributing to the problem is the difficulty in tracking significant declines in bat populations – until their situation is critical. And bats’ low reproduction rates – most females give birth to only one pup per year – make recovery from serious losses especially slow.
Why bats matter
The extinction of bats would put the Earth on the path to natural disaster. One single bat can eat around 5,000 insects per night. Without bats to control insect populations, those insects might have to be killed with pesticides, causing a vicious cycle of more pollution.
Bats also play an important role as pollinators, comparable to honeybees. Many crops and other plants depend on bats to survive. These factors also add up to bats having economic importance.
Bat experts point out that in Europe, Germany has a special responsibility for the protection of migratory bats: Because it is a central point in the migratory hibernation routes, and because its wind turbines are causing a quarter million bat fatalities every year.
To protect the animals, bat advocates say mitigation measures must be implemented to reduce the impact on bats that cross wind farm areas. For example, this could include switching off the turbines when air currents are weak.
That would minimally impact energy production, they argue, while having very positive effects for the migration of the “winged mice,” as they are known in German.
Governments, civil society and citizens are getting more involved in the protection of these animals. But there is still a long way to go, bat advocates emphasize, especially in informing the public better and wiping out negative myths around these animals.
Deforestation in the Amazon rainforest poses a major risk for the survival of many bat species, and subsequently other plants and animals that depend on them. The natural habitats of bats are shrinking, forcing them to into contact with humans – and triggering bat-human conflicts.
Also in Europe, uncontrolled caving endangers huge colonies of bats hibernating in natural and human-made caves. Just one single person going into a cave can awake a whole colony of thousands of bats, who rest in an energy-saving mode. If disturbed, bats must use up their fat reserves to fly out and find a new place to stay – which is not always successful.
After more than 20 years for the international Agreement on the Conservation of Populations of European Bats, great progress has been made in the protection of 53 bat species in Europe, North Africa and the Middle East – especially in education and international cooperation on implementation of protection measures.
However, Eurobats Executive Secretary Streit says there is still much to be done to protect bats from extinction. He emphasizes not only the need for mitigation measures on wind farms, but also points out that citizens can help.
Establishing having bat-friendly gardens, bat boxes on rooftops or joining bat conservation groups and spreading the information in favor of the night flyers are just a few of the things regular citizens can do to help.
|Wind Watch relies entirely
on User Funding