Monarch Butterfly Presence Has Dropped 22%, According to a New WWF Report

Butterfly-watchers and flower-lovers alike, take note: In the forests of Mexico, where they spend the winter, the presence of the magnificent eastern migratory monarch butterfly has dropped by 22%, the World Wildlife Fund (WWF) reports—and experts believe forest degradation and extreme weather conditions are furthering the decline of this important species, which was added to the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species as “endangered” in 2022.

Per the WWF, wintering monarch butterflies once covered more than 45 acres of forest. Now, with this latest decline, they cover just 5.5 acres, as the monarch population has declined drastically over the last 25 years.

The forests eastern monarchs migrate to for winter are no ordinary stretches of land. The Mexican state of Michoacán’s Monarch Butterfly Biosphere Reserve is a UNESCO World Heritage site, where monarchs gather in the 140,000-acre reserve’s forests to stay safe from inhospitable weather. However, in just one year, from 2021 to 2022, the trees in this forest reserve that were lost to disease, drought, or fire tripled from 46.2 acres to 145 acres, an alarming rate that is continuing to decrease the monarch’s habitat.

Concerns surrounding monarch butterfly population declines are not just tied to the beauty of this species: Monarch butterflies, like other pollinators, are vital to our food production.

“It is not just about conserving a species; it’s also about conserving a unique migratory phenomenon in nature,” WWF-Mexico general director Jorge Rickards explained in the WWF’s article on the decline. “Monarchs contribute to healthy and diverse terrestrial ecosystems across North America by carrying pollen from one plant to another. With 80% of agricultural food production depending on pollinators like monarchs, when people help the species, we are also helping ourselves.”

While the presence of eastern migratory monarch butterflies wintering in Mexico has declined, this fall has been countered by a spike in the western monarch population wintering along the California coast. More than 330,000 butterflies were counted in California and Arizona in late 2022, the highest number in the last six years, and the second-straight year of population increase. According to CBS, experts believe this population rebound may even be a result of eastern monarch butterflies flying west and mix with western monarchs, rather than flying to their typical wintering grounds in Mexico.

While that may seem positive for both monarch butterfly populations, the change in migratory patterns is a concern, especially considering the unusual weather California has experienced this winter. Still, it does give conservationists hope that the monarch population can rebound, particularly as public understanding of the importance of these butterflies grows, and more and more people get involved in conservation efforts such as planting milkweed.