There are thousands upon thousands of species of plant and animal that are declining, threatened, or on the verge of going extinct these days. Thanks to never-ending human encroachment and land-use change mixed with the scourge of largely unchecked climate change, one can find a species or type of animal in dire straits wherever one looks. Today, we look at butterflies.
They managed the survey because butterflies, as generally large and charismatic at least in comparison to various other types of insect, are the most monitored insect species around. They compiled data from more than 75,000 individual surveys from 35 monitoring programs, totaling 12.6 million individually counted butterflies. This covered seven distinct geographic regions, and 554 species.
Six of those seven regions saw declines, with only the Pacific Northwest bucking the trend with a 10 percent increase over the study period — though that increase is largely explained by a single species, the California tortoiseshell, which occasionally undergoes “irruptive” population explosions. The worst-hit region was the Southwest, which the authors said was consistent with other studies showing the hits to hot and arid areas as the climate warms.
“Our national-scale findings paint the most complete—and concerning—picture of the status of butterflies across the country in the early 21st century,” wrote the authors, led by Collin Edwards, a conservation biology research associate at Washington State University. Overall, thirteen times as many species they monitored showed declines than increases. Some decreases were catastrophic: 107 declined by more than 50 percent, and 22 declined by more than 90 percent.
In an accompanying Perspective, Florida State scientist Brian Inouye wrote that “Solutions to the problem of declining insect and butterfly populations will have to be as varied as the causes,” focused on everything from pesticide use to to habitat loss. The study authors acknowledged that the climate change angle to this obviously requires international action, but there are localized efforts that can mitigate some of the impacts of rising temperatures on butterfly populations.
“For example, implementing broadly beneficial conservation actions such as native habitat preservation and restoration can increase abundance trends even in the face of climate change, they wrote. “Expansive efforts in conservation planning and action for insects could prevent widespread future losses and create and maintain the environments in which butterflies and other at-risk species can thrive.”
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