A new paper may offer the most comprehensive analysis of just how serious the apocalypse is. The meta-analysis was published in the journal Science on Thursday shows the insect apocalypse is a bit more nuanced than previous research, but we’re still screwing some insects—and, in turn, ourselves
The authors assessed 166 surveys that cover insect data from 1925 to 2018. They found that the average decline in terrestrial insect abundance has been nearly 9 percent per decade. Freshwater insect abundance, on the other hand, have been increasing some 11 percent per decade. This may be a result of water regulations, such as the Clean Water Act in the U.S. It’s nice to know that these creatures can persevere—if humans are wise enough to protect the natural world they depend on.
“It’s a disturbing paper and a paper of hope at the same time,” Hans de Kroon, a professor of plant ecology at Radboud University in the Netherlands who was not involved in this research, told Earther.
The rate of decline in terrestrial critters is definitely not good, but this finding is much more conservative than previous research. Earlier studies found the decline in insect abundance to be closer to an average decline of 3 to 6 percent per year. Every study has its own research methods with an eye on specific regions and time periods. This paper includes studies that cover a wide range of methodologies, but it does rely on robust statistical analysis to synthesize it all.
That’s a clear limitation here, but the result still offers a necessary “rough picture” of what’s going on in the insect world, de Kroon said. What he found remarkable was that despite the variation in studies included in the analysis, the authors were still able to measure a decline among insects. That’s no little thing.
Unfortunately, insect populations require much more monitoring, especially in tropical ecosystems where data is lacking. What we do know so far is largely based on European and North American ecosystems. The authors of the paper suggest that the decline in North America—where the pattern was strongest—was especially influential on the final results. Protected areas are also overrepresented in the data, so we’re not seeing the full impact of human activities may be having on insects.
The analysis also found that Europe saw the steepest decline in terrestrial insects starting in 2005. In North America, these populations have actually been doing better since 2000. As for freshwater bugs, they’ve been thriving in Europe, North America, and Asia since 1990. Unsurprisingly, insect populations in protected areas with less human pressure are seeing less decline than elsewhere.
Brett Seymoure, the author of that study and postdoctoral fellow at the Living Earth Collaborative at St. Louis’ Washington University, told Earther in an email that this new research “adds to the overwhelming evidence that insect populations are declining.” Seymoure said that we should be cautious about the freshwater insect finding, though. Populations may be bouncing back from the damage they faced at the height of water pollution before such environmental protections such as the Clean Water Act existed.
“It is likely that aquatic insect populations were in very rough shape and are now rebounding, which is great, but I don’t think we should take that as an indicator that the insect populations of aquatic habitats are as healthy as they were before the Industrial Revolution,” Seymoure said. “But it is a hopeful trend!”
What is clear, however, is that insects are suffering. Even a 9 percent loss per decade is not good. This is clear pattern that should push us to take action, Doug Tallamy, a professor of entomology at the University of Delaware who did not conduct this study, told Earther. He also worries insects are likely doing worse than the data can show because the baseline data begins during periods when human impact already hurt insect populations. The year 1926 may sound like a long time ago, but environmental degradation has existed as long as humans have.
“We’ve been messing up ecosystems for an awfully long time,” Tallamy said.
Luckily, this new paper shows that insect populations can recover if we repair their habitats. European and North American nations started to clean up waterways, and guess what? The bugs started to come back. If we began to address the harms terrestrial insects face—from stupid lawns, useless lights, and non-native plants—we may actually see some improvement.
“Climate change is one of the most difficult to reverse, but there are a number of easy fixes,” Tallamy said.
An earlier study had found that reducing light pollution could be a quick, affordable way to start addressing this problem. And it’s something anyone can do. Planting native flora and letting your lawn grow wild are two more easy actions to take if you care about insects. And you should because without them, we’re done.