The precipitous decline of the monarch butterfly population over the past three decades — estimates place it at more than 80 percent from the 1990s — has won a reprieve.
Data on monarchs overwintering in Mexico in 2022 show a sharp increase in their numbers, with researchers estimating monarch swarms covering 2.84 hectares (7 acres) compared with just 2.1 hectares (5.2 acres) the previous year.
Craig Wilson is director of the USDA Future Scientists Program and a senior research associate at Texas A&M’s Center for Mathematics and Science Education.
He’s also an expert on the monarch butterfly.
“The numbers came up 350 million,” Wilson said. “So there were pessimistic thoughts that it would not increase, but the 35 percent seems to be correct. The numbers were late coming out because I think data was being held up because of COVID down in Mexico or something, but they’re out there now.”
The migration of monarchs begins in Mexico’s oyamel fir forest, a 10,000-foot mountain aerie just north of Mexico City where the butterflies overwinter.
The trees in the forest provide an umbrella for the monarchs, keeping cold temperatures and precipitation off them as they try to retain fat reserves for the journey north in spring.
But habitat degradation, much of it due to logging, both legal and illegal, and land clearing for agriculture has put the butterflies at risk. The average amount of hectares occupied between 1993 and 2001 was 8.70. For the past decade, however, the average dropped to just 2.62 hectares.
Last year, Mexico officials reported the overwintering monarch population was down 26 percent from 2020.
“The increase in monarch butterflies is good news and indicates that we should continue working to maintain and reinforce conservation measures by Mexico, the United States, and Canada,” said Jorge Rickards, general manager of World Wildlife Fund-Mexico.
“Monarchs are important pollinators, and their migratory journey helps promote greater diversity of flowering plants, which benefits other species in natural ecosystems and contributes to the production of food for human consumption”, Jorge Rickards concluded.