Ecologists found that in 27 years the mass of flying insects in Europe decreased by 76%
European environmentalists, published in PLoS ONE article stated that the biomass of flying insects in the national parks of Germany for 27 years dropped by 76 percent. According to scientists, this trend could lead to “environmental Armageddon”.
Weather fluctuations, land use and habitat modification do not explain this decline and scientists are not yet able to find its cause, said N+1.
Flying insects play a huge role in the functioning of ecosystems. Researchers estimate, they pollinate 80% of wild plants and serve as food for 60% of birds and many mammals and amphibians. Now for some unknown reason, the abundance and diversity of flying insects fall. According to a recent study, between 1990 and 2011, the number of meadow butterflies in Europe declined by 50 percent. The same happens with the number of honeybees, bumblebees and moths.
According to the authors of a new article, such studies are often limited to some well-studied species, but the overall picture may be different.To assess the extent of the problem, the researchers analyzed the mass changes of flying insects for 27 years, from 1989 to 2016. They were placed large gauze traps from March to October of each year 63 natural protected areas in different places of Germany, and captured insects were weighed.
The scientists also noted how some of the factors (changing weather or habitat conditions and land use) influenced the decrease in the number of flying insects.
To analyze the influence of weather, scientists collected data from 169 climatic stations. The use of the land they saw by using aerial photography of forests, natural meadows and agricultural lands, taken in different years. Changing habitat conditions the researchers tracked, counting the number and variety of plants near the traps. They also analyzed the conditions in which grew the plants, including the content of nitrogen compounds and the acidity of the soil, temperature and humidity.
It turned out that on average from season to season, the biomass of insects from 1989 to 2016 fell by 76 percent. In the middle of summer, this figure was reduced to 82 percent. Thus, according to the study authors, reducing the number of individual species of butterflies, moths and bees repeats the General trend to reduce the number of flying insects in Europe. Moreover, the factors that are analyzed by scientists: weather changes, habitat conditions and land use, influence the drop mass of insects only in some places, but did not affect the trend as a whole.
The researchers note that possible causes can be factors that they did not consider climatic changes such as prolonged drought, or the use of insecticides and fertilizers on the fields year-round tillage. A possible explanation could be the fact that all the protected areas where they were catching insects, were located adjacent to agricultural land. However, to understand the reasons for what is happening, we need more extensive research, the authors note.
“It seems that we do vast tracts of land unfit for most life forms, we are now on the road to ecological Armageddon. If we lose the insects, everything will collapse”, – quotes the newspaper The Independent, Professor Dave Goulson from the University of Sussex who took part in the study.
The number of flying insects is reduced not only in Europe. Two years ago, scientists reported on a mysterious illness that has destroyed 42 percent of bees in the United States, and the recent report on the sharp decline of the monarch butterfly in North America.