“It’s just a catastrophic decline,” said Stuart Pimm, an ecologist at Duke University who was not involved in the new listing. “This is one of the most recognizable butterflies in the world.” In 2016, the Monarch butterfly was listed as threatened by the Commission on the Status of Threatened Wildlife in Canada. Now, the International Union for Conservation of Nature has added the migratory monarch butterfly for the first time to its “red list” of threatened species and categorized it as “threatened” — two steps away from extinction. BREAKING NEWS: Migratory Monarch Butterfly Now Endangered, All Surviving Sturgeon Species Now Endangered. Today’s IUCN Red List update: pic.twitter.com/r4XtIizo6Z —@IUCNRedList The team estimates that the monarch butterfly population in North America has declined between 22 percent and 72 percent within 10 years, depending on the method of measurement. “What worries us is the rate of decline,” said Nick Haddad, a conservation biologist at Michigan State University. “It’s very easy to imagine how quickly this butterfly could become even more endangered.” Haddad, who was not directly involved in the listing, estimates that the monarch butterfly population he studies in the eastern United States has declined between 85 percent and 95 percent since the 1990s. “What happens to monarchs is like death by a thousand cuts,” said Karen Oberhauser, an American conservation biologist who specializes in monarch butterflies. “We know that over the last 30 years monarch numbers have been declining, at first really steeply for about the first 15 years, and then more slowly and with large annual variation from year to year.”
The largest migration of insect species
In North America, millions of monarch butterflies undertake the greatest migration of any insect species known to science. After overwintering in the mountains of central Mexico, the butterflies migrate north, reproducing many generations along the way for thousands of kilometers. Offspring arriving in southern Canada begin the journey back to Mexico in late summer. Plants like milkweed, pictured here with a monarch, are important to maintaining the life cycle of monarch butterflies. Insects are threatened by habitat loss, the use of herbicides and pesticides, and climate change. (Michael Charles Cole/CBC) “It’s a real sight and it’s so awe-inspiring,” said Anna Walker, a conservation biologist at the New Mexico BioPark Society, who was involved in determining the new list. A smaller group spends the winters in coastal California and then disperses in the spring and summer to several states west of the US Rockies. This population has seen an even steeper decline than eastern monarchs, although there was a slight recovery last winter. Emma Pelton of the non-profit Xerces Society, which monitors western butterflies, said the butterflies are at risk from habitat loss and increased use of herbicides and pesticides for agriculture, as well as climate change. “There are things people can do to help,” he said, including planting milkweed, a plant the caterpillars depend on. Non-migratory monarch butterflies in Central and South America were not listed as threatened.
