By combining data from the few comprehensive studies that exist, lead author Rodolfo Dirzo, an ecologist at Stanford University, developed a global index for invertebrate abundance that showed a 45 percent decline over the last four decades. Dirzo points out that out of 3,623 terrestrial invertebrate species…42 percent are classified as threatened with extinction.
- Christian Schwägerl/Yale School of Forestry & Environmental Studies, What’s Causing the Sharp Decline in Insects, and Why It Matters July 6, 2016
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, 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.
- Hallmann, CA, M Sorg, et al/PLOS ONE, More than 75 percent decline over 27 years in total flying insect biomass in protected areas 2017
Across North America and Europe, species of birds that eat flying insects, such as larks, swallows, and swifts, are in steep decline…the obvious factor that ties them all together is their diet.
- Gretchen Vogel Where have all the insects gone? May 10, 2017
According to the 2016 State of Birds report published by the North American Bird Conservation Initiative, a coalition that includes the National Audubon Society, temperate grassland and aerial-insectivorous birds on this continent have declined 33 percent since the 1970s—the most rapid drop of any bird group.
- Elizabeth Royte/Audubon Society, The Same Pesticides Linked to Bee Declines Might Also Threaten Birds, Spring 2017
Ok, that was laying out the problem. In subsequent posts, I will explore what might be done about the problem.