Biodiversity of insects is threatened worldwide. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and jeopardize ecosystems.
A citizen science project by the Krefeld Entomological Society measured the biomass of flying insects in protected areas for 27 years.
The journal article,
"More than 75 percent decline over 27 years in total flying insect
biomass in protected areas." authored by Hallmann CA, Sorg M, Jongejans
E, Siepel H, Hofland N, Schwan H, et al. (2017) was published in the Journal
PLoS ONE 12 (10): e0185809 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809