New! Sign up for our free email newsletter.
Science News
from research organizations

More than 75 percent decrease in total flying insect biomass over 27 years across Germany

Changes in weather, land use, habitat do not explain overall decline

Date:
October 19, 2017
Source:
PLOS
Summary:
The total flying insect biomass decreased by more than 75 percent over 27 years in protected areas in Germany, according to a new study.
Share:
FULL STORY

The total flying insect biomass decreased by more than 75 percent over 27 years in protected areas, according to a study published October 18, 2017 in the open-access journal PLOS ONE by Caspar Hallmann from Radboud University, The Netherlands, and colleagues.

Insects play a crucial role in ecosystem functioning, pollinating 80 percent of wild plants and providing a food source for 60 percent of birds. Previous research has shown an overall pattern of decline in insect diversity and abundance, but has focused on single species or taxonomic groups, rather than monitoring insect biomass over an extensive period.

To gain a better understanding of the extent and underlying causes of insect decline, Hallmann and colleagues measured total flying insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany. They found that the average flying insect biomass declined 76% (up to 82% in midsummer) in just 27 years in these locations. Their results align with recently reported declines in vulnerable species such as butterflies, wild bees and moths, but also suggest a severe loss of total flying aerial biomass, suggesting that the entire flying insect community has been decimated over the last few decades.

The researchers found that this dramatic decline was apparent regardless of habitat type, and changes in weather, land use, and habitat characteristics were not able to explain the overall decline. They suggest that large-scale factors must be involved, and additional research should further investigate the full range of climactic and agricultural variables that could potentially impact insect biomass. The authors urge further investigation of causes for this decline, its geographical extent, and how its potential impact on the ecosystem.

Hallman states: "Since 1989, in 63 nature reserves in Germany the total biomass of flying insects has decreased by more than 75 percent. This decrease has long been suspected but has turned out to be more severe than previously thought."


Story Source:

Materials provided by PLOS. Note: Content may be edited for style and length.


Journal Reference:

  1. Caspar A. Hallmann, Martin Sorg, Eelke Jongejans, Henk Siepel, Nick Hofland, Heinz Schwan, Werner Stenmans, Andreas Müller, Hubert Sumser, Thomas Hörren, Dave Goulson, Hans de Kroon. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLOS ONE, 2017; 12 (10): e0185809 DOI: 10.1371/journal.pone.0185809

Cite This Page:

PLOS. "More than 75 percent decrease in total flying insect biomass over 27 years across Germany." ScienceDaily. ScienceDaily, 19 October 2017. <www.sciencedaily.com/releases/2017/10/171019100927.htm>.
PLOS. (2017, October 19). More than 75 percent decrease in total flying insect biomass over 27 years across Germany. ScienceDaily. Retrieved May 10, 2024 from www.sciencedaily.com/releases/2017/10/171019100927.htm
PLOS. "More than 75 percent decrease in total flying insect biomass over 27 years across Germany." ScienceDaily. www.sciencedaily.com/releases/2017/10/171019100927.htm (accessed May 10, 2024).

Explore More

from ScienceDaily

RELATED STORIES