Spotting butterflies is becoming more difficult in the West. New research shows why

When was the last time you spotted a butterfly out West? It may have been awhile, research shows.

Spotting butterflies in the western U.S. could become a rare event. Hundreds of butterfly populations in the region have seen widespread declines over the past several decades, researchers at the University of Nevada, Reno, found.

A group of researchers studied data from 72 locations across the western U.S. from 1977 to 2018 to find out how butterfly populations are faring, according to a Thursday news release from EurekAlert!. The research was published in Science, the American Association for the Advancement of Science’s journal.

What they found is that over the past 40 years, butterfly populations have consistently declined at a rate of about 1.6% every year. Without mitigation, researchers said the decline could continue until the species are extinct.

“The widespread butterfly declines highlight the importance of careful management of the lands that we do have control over, including our own backyards where we should use fewer pesticides and choose plants for landscapes that benefit local insects,” Matt Forister, biology professor at the University of Nevada, Reno, and lead author of the report, said in the news release.

The researchers found that increasing temperatures in the fall and climate change have contributed to the massive decline in butterfly species, even in places that are protected and undeveloped.

“The fact that declines are observed across the undeveloped spaces of the western U.S. means that we cannot assume that insects are okay out there far from direct human influence,” Forister said. “And that’s because the influence of climate change is, of course, not geographically restricted.”

Researchers said a new approach for butterfly conservation is needed and should focus on “suites of species” that have similar habitats instead of focusing on the conservation of a single species at once.

Protecting open spaces without taking action against climate change won’t be enough to save butterfly populations, the researchers said. The declines were found in many different types of land from big cities to national parks, coasts to mountains.

“Western butterfly declines are associated with increasing fall temperatures across the U.S. wildlands,” co-author Katy Prudic a biologist from the University of Arizona, said in the news release. “Conservation, management and restoration on public lands, especially along cooler riparian areas, will be critical for preventing butterfly declines and extinction.”