Insect numbers dropping like flies
Land-use changes on the landscape level are driving local declines in insect biodiversity.
Insects have been disappearing at alarming rates in Germany, and some blame the increase in farming, forestry and other land uses.
A team led by researchers from the Technical University of Munich analysed bug biodiversity at 150 grassland and 140 forest sites using sweep-net samples collected annually between 2008 and 2017. Each site was given a land-use intensity rating based on human activities for five radii between 250 metres and 2 kilometres.
Over the decade, insect biodiversity dropped by a third in both grassland and forest habitats, while biomass declined by two-thirds on grasslands, and two-fifths in forests.
Additionally, more species, particularly the less-mobile varieties, vanished as surrounding farmland cover increased. This reveals the impact of human activity at the landscape scale.
Land-use policies should look beyond individual plots of land and coordinate a regional and national response to prevent further losses.
- Nature 574, 671–674 (2019). doi: 10.1038/s41586-019-1684-3