“Save the butterflies” signs and milkweed plants sometimes greet customers patronizing nurseries. But despite a call to action to protect monarch butterflies, University of Georgia researchers say that population isn’t shrinking.
The International Union for Conservation of Nature announced in July it was declaring the monarch endangered due to species decline.
"[The endangered species] is actually only the subspecies ... that's migratory," said Anna Walker, a butterfly specialist with the New Mexico BioPark Society who helped the IUCN analyze the monarch's population status.
IUCN is only listing this subgroup as endangered, but the subgroup makes up the vast majority of monarchs in the U.S. Walker said population data from monarchs that migrated to California and Mexico have demonstrated long-term decline since the 1990s. IUCN links their endangerment to population loss, as well as habitat loss and impacts from climate change.
Despite the calls of decline and level of concern at an international level, monarch researchers at UGA said their findings throw into question if monarch populations have declined much at all.
Credit: Andrew Davis Tucker, University of Georgia
Credit: Andrew Davis Tucker, University of Georgia
Monarch butterfly decline in question
"For the longest time, we scientists and everybody else thought that the best way to measure the annual size of the population was to measure them at the wintering colonies (in Mexico)," said Andy Davis, a butterfly researcher at UGA. For a variety of reasons, from traffic to climate change, fewer monarch butterflies are arriving in Mexico each winter.
In a study Davis co-authored with William Snyder from UGA's College of Agricultural and Environmental Sciences, they looked at data from more than 135,000 monarch observations from the North American Butterfly Association between 1993 and 2018 to look at how the summer populations of monarch butterflies throughout the U.S. are faring.
What they found is that for the last 25 years, monarch butterflies have been making up the number of butterflies dying during migration with successful summer reproduction. Not only are the butterflies holding their populations steady, but Davis said there's been a tiny growth of 1.6%.
While Davis said the population isn't in precipitous decline, there still needs to be an overwintering population sufficient enough to keep up that summertime boom of reproduction.
Davis said he recognizes these findings confuse the popular narrative about the monarch's decline. For conservationists, the monarch is a poster child for species decline and motivates many to support conservation efforts.
"If you look at the numbers of monarchs across the country, and in Canada, they're actually one of the most, if not the most, abundant butterflies in North America right now," Daniels said. "Not used to be. Right now."
In fact, Daniels said, the monarchs are faring better than about two-thirds of butterfly species in the U.S.
Credit: Norman Winter, Mississippi State University
Credit: Norman Winter, Mississippi State University
Endangered status
The IUCN's declaration that monarchs are endangered doesn't spell much change for the species, at least not legally. The U.S. Fish & Wildlife Service, which governs what species are considered endangered in the U.S., said they haven't changed their designation.
Fish & Wildlife said it will continue to monitor the monarchs. While they are a candidate for listing as endangered, the agency has prioritized more threatened species based on the "degree and immediacy of threats." If endangered status remains warranted, USFW intends to propose listing the monarch in 2024.
Is milkweed the answer?
When it comes to what people can do to help butterfly populations, a popular action is to plant milkweed, a significant food source and breeding ground for monarchs.
Davis said he doesn't recommend planting milkweed. Since summertime monarch populations are doing well, the logical inference is monarchs already have what they need to survive.
Planting milkweed can do more harm than good, said Davis. Even from local nurseries, he said it's common to mistakenly get a nonnative species of milkweed which can throw off monarch's migration habits.
As an alternative, he suggests a lawn care practice that will benefit all bugs: Take a little corner of your lawn space and just let it go.
Let it get messy and wild, because that's where bugs thrive best and can play their roles pollinating, becoming food for baby birds and beyond.
Credit: Photo courtesy of University of Georgia
Credit: Photo courtesy of University of Georgia
Jaret Daniels, assistant professor and curator for the McGuire Center for Lepidoptera & Biodiversity at the Florida Museum of Natural History, is working on a project to create a certification for nurseries' milkweed plants. The certification would help well-meaning gardeners make environmentally appropriate choices in what they plant.
Additionally, his department works with the U.S. Department of Transportation to rebuild monarch habitats in targeted areas like along roadsides or in retention basins.
"It's not some endangered rare organism that occurs only in one island of the Florida Keys where the general public really can't do a lot to help," Daniels said. "The monarch is a cosmopolitan species."
It's prevalence in schoolyards and gardens boosts the species popularity, Daniels said. But they serve a much larger end: The monarch is like a bellwether organism that can demonstrate biodiversity loss is happening and now affecting more common species. Ultimately, he said, the loss is a much bigger problem 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.
This article originally appeared on Savannah Morning News: Are monarch butterflies endangered? Georgia researchers debate need for designation
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