Insect Collapse Might Be Even Worse Than Feared

The painted lady (Vanessa cardui) a butterfly species found in many parts of Europe - but for how long? Sebastian_Photography/Shutterstock

Since the 1990s, a handful of studies have sounded the alarm for an upcoming bug-apocalypse, set to decimate the world’s population of insects and spiders in the coming decades.

Now, a new study has joined the pile of mounting evidence that suggests the planet’s insects are on the verge of a catastrophic problem. Reporting in the journal Nature this week, a detailed new study has warned that the scale of insect decline in Europe might be more profound than previously feared. 

A team of ecologists led by the Technical University of Munich has carried out a survey of arthropods (both insects and spiders) across 150 grasslands and 140 forests across Germany between 2008 and 2017. They assessed the health of the area’s bug life using three criteria: biomass, the abundance of a species, and the number of different species. They found that all three metrics were on a steep decline at 67 percent, 78 percent, and 34 percent, respectively. 

"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," Wolfgang Weisser, professor of Terrestrial Ecology at the Technical University of Munich, said in a statement.

Nearly 2,700 species were studied in total. Over the decade of study, rare species suffered the steepest decline in numbers, to the extent that some had disappeared from the studied regions completely. Meanwhile, the number of common species remained relatively steady or were even on the rise.

The cause of the steep slump is multi-faceted, but the intensification of agriculture bears much of the responsibility. Their findings showed that the biggest losses in grasslands were surrounded by intensively farmed land. Not only does farmed land disrupt or destroy natural habitat, but it can also cut off their pathways to other habitats. For example, they found that insect groups that migrate and cover more distance in forest areas suffered worse declines.

Furthermore, intense agriculture can often involve the use of pesticides, which are known to affect many species of arthropod. Although the researchers note that no pesticides were applied at any of the sites, they say the studied species could still be affected by the drift and transport of pesticides via air or water. 

While small community projects might have their place in the struggle, the study warns that coordinated large-scale initiatives and policy changes are needed to avoid a potentially catastrophic collapse. 

"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," concluded study author Dr Sebastian Seibold. "To stop the decline, however, our results indicate that more coordination is needed at the regional and national levels."

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