Monarch butterflies are among the most popular in Arizona and across the United States.
The U.S. Fish and Wildlife Service (Service) is proposing Endangered Species Act (ESA) protections for one of North America’s most iconic migratory species and recognizable insects: the Monarch butterfly.
The western migratory monarch butterfly population has declined by more than 95% since the 1980s, putting it at risk of extinction by 2080.
Meanwhile the eastern migratory population has declined by about 80%.
The Service has published a proposal to list the monarch butterfly as a threatened species and designate critical habitat on the Federal Register, inviting public input through March 12, 2025.
If ESA protections are approved, federal funding could be allocated for habitat conservation.
Kathleen Prudic, assistant professor and associate director in the School of Natural Resources and the Environment at University of Arizona, studies how climate change impacts pollinators.
She describes the two populations of monarch butterflies as “flyaways,” and explains that the eastern flyaway is the population most familiar to the public.
This population ranges from northeastern Canada to Central Mexico.
“Those are the pictures you see of the millions of butterflies overwintering on those Oyamel firs,” Prudic said.
Monarchs overwinter or migrate to better climates, and enter a dormant state to hibernate.
The western flyaway stretches from the Great Basin, as far east as Colorado and Idaho, with monarchs returning in winter to California’s coastal pine trees.
In Arizona, there’s a blending of the eastern and western flyaways, resulting in resident populations that remain year-round without migrating.
“Monarchs are not the worst off of all western butterflies in their rate of decline but they’re certainly not doing spectacularly and not increasing,” Prudic said.
The species faces significant threats including the loss of migratory and overwintering habitats and climate change-driven hotter temperatures and reduced water sources, all of which contribute to population declines.
“In some places like the West, and this is what we’re sort of predicting with our modeling, is that it’s going to get worse and then there’ll be some places in the Pacific Northwest or Northeast, where it might be a better habitat for a lot of things,” Prudic said.
Exposure to insecticides also poses a serious challenge.
“Pollinators are helping create the next generation of plants, so they are helping facilitate plant reproduction,” Prudic said, “Without that, you would have a world where you would have a lot less poor water quality, you would have poor soil, you have much more soil erosion.”
Pollinators like the monarch help stabilize soil, without butterflies, and their absence could even impact air quality.
Prudic notes that while the future of the monarch butterfly remains uncertain, federal protections could offer insight for effective conservation and management practices.
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