Death of bats from windmills harms agriculture
(ORDO NEWS) — The death of numerous bats colliding with windmill blades can have long-term consequences for animal biodiversity in rural areas. This, in turn, can have a negative impact on agriculture and forestry.
Until now, scientists have only assumed that the death of numerous red noctules ( Nyctalus noctula ) from wind turbine blades can have negative environmental consequences.
Now the hard data has emerged: by studying the diet of bats, the authors of the new work assessed the degree of influence of these modest animals on the entire ecosystem in rural areas in Germany.
The researchers analyzed the stomach contents of 17 red evening bats found under wind turbines: using PCR amplification and high-throughput sequencing , scientists looked for genetic “traces” of insects eaten by bats before death.
Since food is quickly digested in the mouse stomach, this method of identifying victims is much more reliable than the “classical” visual method, when a specialist in preserved chitin fragments establishes the species of an insect.
In total, 46 species of insects were identified, most of them were beetles and butterflies that live both in the fields and in the forest or even in the swamp.
About 20 percent of the identified insect species are considered pests of agriculture and forestry: for example, one larva of the acorn codling moth ( Cydia splendana ) can damage up to four acorns, and the chestnut weevil ( Curculio elephas ) is often found in chestnut fruits already on the market
Separately, it is worth noting their prevalence in the diet of noctules: for example, the weevil was found in 18% of the studied stomachs, the pine cocoon moth ( Dendrolimus pini ) – in 24%, and the short-horned beetle ( Spondylis buprestoides ), one of the most common pests of coniferous plantings – in 41%.
In other words, insect pests are not accidental, but quite common components of the bat diet, and the disappearance of bats may lead to an increase in the number of pests, which will have to be compensated by chemical insecticides.
Providing humanity with green energy, windmills, in turn, deprive us of the free “services” of bats to control the number of harmful insects.
Estimates have shown that more than ten bats per year die on each wind turbine. Considering that about 300,000 windmills operate on the German mainland, the number of dead bats could reach millions.
As measures to combat this, they are already introducing a temporary shutdown of windmills during the period of greatest activity of bats, which can reduce the number of dead animals to one or two per year.
Unfortunately, switchable windmills have not yet become widespread, and old models make up about 75% of all German windmills.
This means about 200,000 dead mice per year, which, given the slow breeding rate of noctules, could bring the once abundant species to the brink of extinction.
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