Why Monarch Butterflies Aren’t Getting Endangered Species Status

Monarch butterflies qualify for protections, but 161 other species have higher priority

A monarch butterfly sits on a globe thistle on a green background
America's eastern monarch population has fallen by about 80 percent, and the western population by 99 percent, but the Fish and Wildlife Service doesn't grant endangered status to specific populations of invertebrate species. Photo by DaPuglet via Flickr under CC BY-SA 2.0

Monarch butterflies will not be added to the federal endangered species list this year, the U.S. Fish and Wildlife Service announced on Tuesday. The agency found that the butterfly qualifies for the status but, for now, the species is precluded from protections and will be reconsidered annually until 2024, according to the report published in the Federal Register.

The orange-and-black insects have faced decades of difficulties. In 40 years, America’s eastern population of monarchs, which flock to Mexico each winter, has seen its numbers drop by about 80 percent, reports Farah Eltohamy for National Geographic. Western monarchs, which overwinter in California, have lost closer to 99 percent of their population, reports Elizabeth Pennisi for Science magazine.

Because monarch butterflies already have some dedicated federal, state and private conservation programs, and because there are healthy populations elsewhere around the globe, they aren’t a high priority for endangered status. About 161 species are higher priority for protections, according to the statement. To some conservation biologists, the decision is disappointing.

“Getting put on the candidate waiting list is better than getting denied,” says Center for Biological Diversity conservation biologist Tierra Curry to Science magazine. The Center was an original member of the group that sued the FWS to consider monarchs for endangered status. Curry adds, “For the western population, protection was needed yesterday…The longer listing is delayed, the more difficult and expensive recovery planning becomes.”

Adding the butterfly to the endangered species list would have required the government to create and fund a comprehensive recovery plan. For some animals, specific groups can receive or lose endangered status independent of animals living in other regions. For instance, gray wolves have faced several rounds of state-specific de-listings. But invertebrates like monarch butterflies can only be considered as one national population, per Science magazine.

The butterflies have been snubbed for their spinelessness before. Last month, a court ruled that California’s Endangered Species Act doesn’t apply to insects, National Geographic reports. California’s butterfly population has fallen from 200,000 in 2017, to about 29,000 in 2018 and 2019, to less than 2,000 in this year's autumnal count.

But several programs are already taking steps to protect monarch butterflies. This spring, the Western Monarch Mystery Challenge asked the public to send in photographs of monarch butterflies spotted during March and April, Smithsonian reported at the time. And some homeowners have begun planting nectar-rich plants and milkweed in their yards in order to provide migrating monarchs with food.

Milkweed is the only food that monarch caterpillars can eat, and it used to grow between crops in farmers’ fields. Today it’s largely removed by weedkillers like Roundup, Catrin Einhorn reports for the New York Times. Now, a federal program pays farmers to preserve acres of land for pollinator-friendly habitat.

Private and federal efforts have provided about 500 million milkweed stems for monarchs, and “have made and continue to make a big difference,” says FWS regional director for the Great Lakes, Charles Wooley, to Science magazine.

The programs may be changing monarchs’ habits, though. Non-native, tropical milkweed doesn’t die off each winter, so butterflies might not realize the necessity of migrating. (Some monarchs in Florida have already decided to stay put through the winter, rather than return to their normal wintering grounds in Mexico, per Science.) And the long-lived milkweed may accumulate a caterpillar-killing parasite, reports National Geographic.

“While all of these people that care about monarchs are doing a lot of positive things, there are a lot of negative things happening at the same time,” says University of Wisconsin conservation biologist Karen Oberhauser to the New York Times. “We’re running as fast as we can to stay in the same place.”

Climate change, insecticides, habitat loss and wildfires may all contribute to the decline in monarch populations, but “we don’t know, and we don’t understand it,” says ecologist Arthur Shapiro, of University of California, Davis, who has studied north-central California butterfly populations for nearly five decades, to National Geographic.

University of Kansas, Lawrence insect ecologist Orley Taylor tells Science magazine that the FWS’ decision "is the right one at this time."

"It acknowledges the need for continued vigilance, emphasizing the need to continue support for programs that create and sustain habitats for monarchs," Taylor says.

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