Study reveals alarming decline in insect biomass worldwide

Over the past several years, beekeepers around the world have struggled to understand and overcome ever increasing hive losses. Now, researchers have discovered honeybees are not the only threatened species. An exhaustive study of insect density in the biosphere by Radboud University, Institute for Water and Wetland Research, Animal Ecology and Physiology & Experimental Plant Ecology in the Netherlands, has measured an alarming 75% reduction in total insect density in protected sanctuaries over the past 27 years. You read that right, 75%! Even worse, winged insect density has dropped a whopping 87%!!

These findings are both alarming and frightening. Aside from pollination, insects are an integral part of the biosphere and function at the lowest levels in a healthy ecology. Without insect interaction, life from the ground up becomes increasingly difficult and problematic. While many reasons for this unimaginable decline are being considered, scientists are no closer today to understanding let alone mitigating the trend.

Below is the abstract of this study published on PLOS|One. Well worth your read the study raises many intriguing questions about the future of Earth’s ecology.

Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76% and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape. [Read More]