(CN) — Citing plummeting population numbers for one of America’s favorite pollinators, the leading international scientific body on extinction classified the monarch butterfly as endangered Thursday.
“To preserve the rich diversity of nature we need effective, fairly governed protected and conserved areas, alongside decisive action to tackle climate change and restore ecosystems,” Bruno Oberle, director general of the IUCN, said in a statement announcing that the migratory monarch has been put on the organization's Red List.
The IUCN called the risk of extinction greatest for the western population of monarch butterflies, with populations declining roughly 99.9% between the 1980s and 2021 — from as many as 10 million to 1,914 butterflies. The eastern monarch butterflies’ population shrank as well, the IUCN found, down 84% from 1996 to 2014.
Overall, the group estimated that, depending on the measurement metrics used, monarch populations have shrunk by between 22% and 72% in the last decade alone.
“Concern remains as to whether enough butterflies survive to maintain the populations and prevent extinction,” the organization said.
On the IUCN’s rubric, endangered is just two steps away from extinct.
Anna Walker, a member of the IUCN’s butterfly and moth specialist group and a species survival officer at the New Mexico BioPark Society, led the international group’s monarch butterfly assessment. While Walker lamented the monarchs’ numbers Thursday, she seemed optimistic the situation could turn around.
“It is difficult to watch monarch butterflies and their extraordinary migration teeter on the edge of collapse, but there are signs of hope,” Walker said in a statement. “So many people and organizations have come together to try and protect this butterfly and its habitats.”
Scientists have linked the decline of monarchs to the widespread loss of milkweed, an important food source for the butterfly and the only plant on which the insect can lay its eggs. Studies have found that people can aid in the preservation and continued existence of the monarch by planting milkweed, the only host plant for the iconic species.
Environmentalists have also blamed the butterfly's plummeting numbers on federal approval of glyphosate, the key ingredient in Monsanto's Roundup. Use of the weed killer spread in the 1990s with the creation of genetically engineered Roundup Ready crop strains that are resistant to glyphosate. The majority of U.S. corn and soy fields are treated with the chemical.
One more culprit in the decline of the Monarch has been longer, hotter autumns due to climate change. According to one study published this spring, butterfly chrysalises exposed to these conditions lost more weight and spent more energy on staying alive than those exposed to more mild conditions. While the former didn’t all die immediately, the more extreme fall temperatures made them far less likely to make it to spring alive. Severe weather also kills butterflies.
Walker emphasized Thursday that humans can help monarchs on all of these fronts.
“From planting native milkweed and reducing pesticide use to supporting the protection of overwintering sites and contributing to community science, we all have a role to play in making sure this iconic insect makes a full recovery,” she said.
Another hurdle, the IUCN added Thursday, is that “legal and illegal logging and deforestation to make space for agriculture and urban development has already destroyed substantial areas of the butterflies’ winter shelter in Mexico and California.”
Both eastern and western native populations are known for their migrations from Mexico and California in the winter to the U.S. and Canada in the summer, undertaking the longest migration of any insect species known to man.
Stephanie Kurose, senior endangered species policy specialist at the Center for Biological Diversity, said that while the IUCN distinction marks an important recognition of the danger the butterfly faces, “we can and must do more.” She faulted the U.S. federal government for not protecting monarch butterflies under the Endangered Species Act.
“The Fish and Wildlife Service must stop sitting on its hands and protect the monarch butterfly under the Endangered Species Act right now, instead of hiding behind bureaucratic excuses,” Kurose said, pressing the Biden administration.
Scott Hoffman Black, executive director of the invertebrate conservation group the Xerces Society, agreed with this take Thursday, saying he was “very supportive of listing the migratory monarch as endangered.”
“We have seen the numbers dramatically decline over the years in our western monarch count and know this species needs our help,” he said in a statement.
According to a letter sent to lawmakers by more than 80 conservationist groups in 2021, an annual $100 million in conservation funding on the federal government’s tab could help protect the monarch butterfly from extinction.
Still, other actions being taken by the president could help the monarchs indirectly.
On Wednesday President Joe Biden repealed a Trump-era federal regulation that had shaken up protections for endangered or threatened species, giving landowners deference over habitat designations by claiming they would face economic harm.
Discretion over habitat decisions previously was vested in the Interior Department, but the rule instituted by former President Donald Trump gave greater significance to the financial interests of private landowners. It was the last of Trump-era alterations to the Endangered Species Act that Biden had not yet overturned. Wednesday’s announcement restores the authority of the Interior Department to make decisions about when and if a protected habitat should be established.
Notably, nonmigratory monarch butterflies, located in Central and South America, have not been marked endangered.
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