Insect populations disappearing at alarming rate, scientists warn

MUNICH — Many people view insects as mere annoyances, between the buzzing, biting, and infiltration of their homes. Within the scope of modern life it can be easy to forget that all of those bugs are essential components to the balance of nature on planet Earth, and each species plays a specialized role in the beautiful world we all call home. Unfortunately, a new study based out of Germany finds that insect populations are disappearing at much faster rates than anyone expected.

According to researchers at the Technical University of Munich, the number of insect species within many areas of Germany have decreased by about one third over the past 10 years. Grasslands located close to farmed land were cited as the areas mainly affected, but forests and even protected areas have also seen significant insect population decline.

Previous sets of research had already concluded that Germany is home to far fewer insects than it once was 25 years ago.

“Previous studies, however, either focused exclusively on biomass, i.e. the total weight of all insects, or on individual species or species groups. The fact that a large part of all insect groups is actually affected has not been clear so far,” explains Dr. Sebastian Seibold, a scientist with the Terrestrial Ecology Research Group at TUM, in a release.

For the study, insect populations across various areas of Germany (Brandenburg, Thuringia, and Baden-Württemberg) were surveyed between 2008-2017. Over the course of the 10 year survey period, over one million insects were collected from 300 different locations. Shockingly, the majority of the almost 2,700 investigated insect species were found to be in decline. In more recent years, some of the more endangered species couldn’t be found at all in certain German regions.

Across both forest areas and grasslands, there were roughly one third fewer insects in 2017 compared to 2008.

“Before our survey it was unclear whether and to what extent forests were affected by the insect decline as well,” Seibold adds.

Since beginning observation in 2008, the research team noted a decrease of roughly 40% in insect biomass within studied forests. For grasslands, the decline was even more apparent, with insect biomass decreasing to a paltry one third of its former level.

“A decline on that scale over a period of just 10 years came as a complete surprise to us – it is frightening, but fits the picture presented in a growing number of studies,” comments co-initiator Wolfgang Weisser, professor of Terrestrial Ecology at TUM.

Every single type of forest and grassland area investigated by researchers saw a decline in insect life; sheep pastures, meadows that are maintained and fertilized three to four times annually, and various types of forests including unused protected areas.

Interestingly, the areas where these insects live seem to be playing a deciding factor in which species are declining. Regarding areas close to intensively farmed land, the insects that were the most affected were those unable to travel far distances. Conversely, in forest areas, the insect groups that saw the largest declines were those that typically travel long distances.

“To decide whether it is a matter of the more mobile forest-dwelling species having more contact with agriculture, or whether it has something to do with living conditions in the forests, further study will be needed,” comments former TUM researcher Dr. Martin Gossner.

“Current initiatives to address insect losses are overly concerned with the cultivation of individual plots of land and operate independently of one another for the most part,” Dr. Seibold concludes. “To stop the decline, however, our results indicate that more coordination is needed at the regional and national levels.”

The study is published in the scientific journal Nature.

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