Dramatic Decline in Western Butterfly Populations Linked to Fall Warming
Published:09 Mar.2021    Source:University of Arizona

Western butterfly populations are declining at an estimated rate of 1.6% per year, according to a new report to be published this week in Science. The report looks at more than 450 butterfly species, including the western monarch, whose latest population count revealed a 99.9% decline since the 1980s.

"The monarch population that winters along the West Coast plummeted from several hundred thousand just a few years ago to fewer than 2,000 this past year," said Katy Prudic, an assistant professor of citizen and data science in the University of Arizona School of Natural Resources and the Environment and a co-author of the report. "Essentially, the western monarch is on the brink of extinction, but what's most unsettling is they are situated in the middle of the pack, so to speak, in our list of declining butterfly species."