A ten-year study has revealed that the number of insects, species, and biomass has significantly decreased in all regions of Germany. Green and forest areas near agricultural land have been particularly affected. Despite Germany’s environment appearing to be in good condition compared to other industrialized countries, a study published in the journal PLOS ONE in 2017 showed that the biomass of insects in nature reserves had decreased by 76% in 27 years. Furthermore, a study published in the scientific journal Insect Conservation and Diversity in 2019 found that the number of butterflies in the vicinity of agriculture had decreased by two-thirds. Now, scientists from the Technical University of Munich and the Julius-Maximilians-University of Würzburg have published a study in the prestigious journal Nature that assesses the overall situation of the insect population in Germany.
During the ten-year study from 2008 to 2017, the scientists led by Sebastian Seibold examined insect populations in 140 forest areas and 150 grassland areas, recording biomass, species, and frequency. They found over one million insects from 2,700 different species. The results of the study are alarming, with no grass or forest area spared from the decline in insects. On average, the number of species in grasslands decreased by 34%, the biomass of arthropods decreased by 67%, and the frequency decreased by 78% over the ten-year period. The researchers also found a significant decline in insect populations in the forest areas they examined, with biomass decreasing by 41% and the number of species decreasing by 36% compared to 2008.
The study’s authors emphasize that the decline in insects affects all levels of the food chain, including herbivores, fungus and detritus feeders, omnivores, and predatory arthropods. While previous studies have not shown that the decline affects all groups, the data collected in this study confirms that the decline affects species, frequency, and biomass. The study does not investigate the reasons for the decline, but the data collected suggests that the decline is particularly strong in areas near agriculture. The authors call for coordinated measures across landscapes and regions to counteract the decline in open and forested habitats, emphasizing the need for a paradigm shift in land use on a national and international level.
