Monarch Butterflies Aren’t Near Endangered Status, UGA Researchers Say

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“Save the butterflies” signs and milkweed plants sometimes greet customers who frequent the nurseries. But despite a call for action to protect monarch butterflies, University of Georgia researchers say the population isn’t declining.

The International Union for Conservation of Nature announced in July that it was declaring the monarch butterfly endangered due to species decline.

“[The endangered species] is actually just the subspecies … that is migratory,” said Anna Walker, a butterfly specialist at the New Mexico BioPark Society who helped IUCN analyze the monarch’s population status.

The IUCN only lists this subgroup as endangered, but the subgroup makes up the vast majority of monarchs in the United States. The IUCN links their endangerment to population loss, as well as habitat loss and the impacts of climate change.

Despite calls for declines and the level of concern internationally, UGA monarch researchers said their findings call into question whether monarch populations have declined much.

Description: Assistant researcher Andy Davis with a monarch butterfly under a microscope in his lab in the Ecology Building on campus.

The decline of the monarch butterfly in question

“For a very long time, we scientists and everyone else thought that the best way to measure annual population size was to measure them at overwintering colonies (in Mexico),” said researcher Andy Davis. on butterflies at UGA. For a variety of reasons, from traffic to climate change, fewer monarch butterflies arrive in Mexico each winter.

In a study Davis co-authored with William Snyder of UGA’s College of Agricultural and Environmental Sciences, they looked at data from over 135,000 monarch sightings from the North American Butterfly Association between 1993 and 2018 to examine how summer populations of monarch butterflies across the United States are doing.

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What they found was that for the past 25 years, monarch butterflies have compensated for the number of butterflies that die during migration with successful summer breeding. Not only are the butterflies keeping their populations stable, but Davis said there has been a small growth of 1.6%.

While Davis said the population is not in precipitous decline, there must still be a sufficient wintering population to sustain this summer breeding boom.

Davis said he recognizes the findings confound the popular narrative of the monarch’s decline. For conservationists, the monarch is an example of species decline and motivates many to support conservation efforts.

“If you look at the number of monarchs across the country and in Canada, they’re actually one of the most abundant, if not the most abundant, butterflies in North America right now,” Daniels said. “Not used to be. Right now.”

In fact, Daniels said, monarchs fare better than about two-thirds of butterfly species in the United States.

An orange monarch butterfly feeding on the blue-lavender flowers of the Blue Fortune agastache gives this garden a vibrant complementary color palette.

Endangered status

The IUCN statement that monarchs are endangered doesn’t mean much change for the species, at least not legally. The US Fish & Wildlife Service, which regulates species considered endangered in the United States, said it had not changed its designation.

Fish & Wildlife said it will continue to monitor monarchs. While they are candidates for listing as endangered species, the agency has prioritized the most endangered species based on “degree and immediacy of threat”. If endangered status remains warranted, USFW intends to propose the monarch for listing in 2024.

Is milkweed the answer?

As for what people can do to help butterfly populations, a popular action is to plant milkweed, an important food source and breeding ground for monarch butterflies.

Davis said he doesn’t recommend planting milkweed. Given that summer monarch populations are doing well, the logical conclusion is that monarchs already have what they need to survive.

Planting milkweed can do more harm than good, Davis said. Even at local nurseries, he said it’s common to mistakenly get a non-native species of milkweed that can disrupt the monarch’s migration habits.

As an alternative, he suggests a lawn care practice that will benefit all insects: Take a small patch of your lawn and just let it go.

Let it get messy and wild, because that’s where insects thrive best and can perform their pollinator role, becoming food for the baby birds and beyond.

A monarch butterfly with outstretched wings, showing off its famous orange and black colors.

Jaret Daniels, assistant professor and curator of the McGuire Center for Lepidoptera & Biodiversity at the Florida Museum of Natural History, is working on a project to create certification for nursery milkweed plants. Certification would help well-meaning gardeners make environmentally conscious choices in what they plant.

Additionally, his department is working with the U.S. Department of Transportation to rebuild monarch habitats in targeted areas like along roads or in retention ponds.

“It’s not a rare endangered organism that only exists on a single island in the Florida Keys where the general public really can’t do much to help,” Daniels said. “The monarch is a cosmopolitan species.”

Its prevalence in schoolyards and gardens is increasing the species’ popularity, Daniels said. But they serve a much broader purpose: the monarch is like an indicator organism that can demonstrate that biodiversity loss is happening and now affecting more common species. Ultimately, he said, loss is a much bigger issue for humanity than most realize.

Marisa Mecke is an environmental journalist. She can be reached at mmecke@gannett.com or by phone at (912) 328-4411.

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