Monarch Butterfly Populations Remain Stable Despite Scientists’ Warnings Of Extinction, Study Finds

Topline

Monarch butterfly breeding populations have remained stable since 1993, a study published in Global Change Biology on Friday found, disputing previous concerns raised by scientists that the butterfly species could face extinction because of dwindling winter colonies affected by climate change.

Key Facts

Researchers at the University of Georgia—who analyzed data on 135,000 monarchs from the North American Butterfly Association between 1993 and 2018—found butterfly population growth during the summer compensated for declines in the winter.

Monarch butterfly relative abundance—a measure of how common or rare the species is relative to others—grew by more than 1% each year since 1993, scientists found.

Mexico has seen declining populations of winter butterflies in recent years possibly because fewer monarchs have been making the trek south due to worsening weather conditions, but summer breeding in North America made up for those losses, researchers said.

Researchers discovered monarch butterflies are actually “one of the most widespread butterflies in North America,” according to Andy Davis, a study author and assistant research scientist at the University of Georgia’s Odum School of Ecology.

Researchers warned rising temperatures resulting from climate change may still pose a threat to other butterfly species as well as a host of insects.

Crucial Quote

“There’s this perception out there that monarch populations are in dire trouble, but we found that’s not at all the case. It goes against what everyone thinks, but we found that they’re doing quite well,” Davis said.

Big Number

500. That’s how many eggs a single female monarch butterfly can lay, making the species “capable of rebounding tremendously,” Davis said.

Key Background

A host of insect species are in decline due to factors such as habitat loss, pesticides and climate change, putting human beings and the broader ecosystem at risk because of the role insects play in processes such as plant pollination and breaking down waste. While several butterfly species are in danger, monarch butterflies have become the “public face” of insect declines, according to researchers. Reports and studies in recent years have suggested western monarchs are on the brink of extinction, largely because of dwindling winter colonies in areas like Mexico and California. But research to date on whether monarch breeding populations are in consistent decline during all seasons has been less clear. The Global Change Biology study is one of the largest and most comprehensive assessments of monarch butterfly breeding patterns yet, according to researchers.

Further Reading

Monarch butterflies denied endangered species listing despite shocking decline (National Geographic)