For many Americans, the monarch butterfly is an iconic part of childhood — a real world insect from which to learn about caterpillars, cocoons, metamorphosis, and migrations. But monarch butterfly populations have declined precipitously in recent years, dropping an average of 90 percent in the last two decades.
On Monday, the US Fish and Wildlife Service announced it would conduct a year-long review of the monarch — the first step in an agency process for determining if the insect should be protected under the Endangered Species Act.
The review comes in response to a petition filed in August by three environmental groups and a prominent monarch researcher, who allege that increased use of herbicides on corn and soybean crops is the main driver of the decline, killing off the only plant monarchs consume when they are caterpillars.
"I think the agency's review is an acknowledgment of how much trouble they're in and the effort that it's going to take to save them," Tierra Curry, a senior scientist at the Center for Biological Diversity, one of the organizations that filed the petition, told VICE News.
Monarchs reached their lowest point last winter, at an estimated 35 million butterflies. In the mid-1990s, they numbered around one billion. The largest population of monarchs, known as the eastern migratory population, lives east of the Rocky Mountains and migrates to Mexico in the winter. A smaller western population migrates to coastal California.
FWS will review published research on monarchs and consider public comment to determine if the butterflies are in danger of extinction in the near future. Depending on the finding, the agency could then discuss protections it might enact, like setting aside preserved grounds.
"This is welcome news not only for the monarch, but for other species, because it will draw attention to the stresses that are threatening their existence," James Hansen, a climate scientist at Columbia University's Earth Institute, told VICE News. "The major stress for monarchs is probably herbicides, but climate change is a contributing factor."
Female monarchs lay their eggs on milkweed, a hardy plant that in the 1980s ranged across 26 million acres of land in the Midwest. In the corn and soybean fields of Iowa, the state where milkweed was most prevalent, the plant declined by nearly 97 percent between 1999 and 2009 — largely due to an increase in the way glyphosate, a Monsanto-developed herbicide, is used on corn and soybean crops, says CBD and the other petitioners.
"The females will fly through the landscape looking for the milkweed plants and it's basically being wiped off the midwestern landscape," Curry told VICE News. "So they just can't find the plants to put their eggs on."
'Farmers are part of the solution here.'
Monsanto first introduced glyphosate, known by its brand name Roundup, in 1974. In 1996, the company introduced Roundup Ready crops, which are engineered to survive application of Roundup and allow for the pesticide to be applied in greater amounts and more frequently. In 2013, 157 million acres of corn and soybean — nearly the size of Texas — were treated with glyphosate, a nine-fold increase over the 17 million treated acres in 1995.
Monarchs are also vulnerable to development, habitat loss, and climate change. In the Midwest, monarch habitats are being converted into farmlands, further shrinking the butterfly's available range, and development on the West Coast is encroaching on the western population's wintering habitat. Climate change brings its own host of possible threats: the spread of parasites and disease and unsuitable temperatures in both winter and summer habitats.
"I suspect that their numbers have passed a critical level that hampers reproduction during the annual migration, simply because there are not enough male-female encounters during the long journey," Hansen told VICE News. "Even if so, however, the number of migrating butterflies may recover over time if food — milkweed — and climate conditions improve."
The FWS could enact a broad array of protections if the agency designates the monarchs as endangered. But Curry said they could potentially develop guidelines for farmers and ask them to set aside areas where milkweed can grow. Some universities and other organizations have already begun to do this independently, encouraging the public to plant milkweed and create "monarch way stations" at homes, schools, parks, and other areas.
"Monarchs have successfully bred on farmland forever up until now," Curry told VICE News. "So farmers are part of the solution here."
Monarchs were once highly threatened by logging in Mexico, which was destroying their winter habitat, Curry said. But in 1986, Mexico designated a protected area that would eventually become the 139,000-acre Monarch Butterfly Biosphere Reserve, recognized as a UNESCO Heritage site in 2008. The reserve covers an estimated 70 percent of the wintering butterfly population, according to UNESCO.
"Mexico has successfully reigned in logging," Curry told VICE News. "Now the ball is really in the court of the US to protect the summer habitat."
Follow Laura Dattaro on Twitter: @ldattaro
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