butterfly on a flower

Peter Miller/Flickr (CC BY-NC-ND 2.0)

California’s monarch butterflies struggle against extinction

Times are tough for monarch butterflies across the United States, but a new study in Biological Conservation shows that a subset of the animals that overwinter along the California coast are in particularly severe trouble. Based on a combination of historical data and citizen science, researchers have calculated that the butterfly population there has declined 97% since the early 1980s, from 10 million to about 300,000, Sierra reports. If the current trend continues, the butterflies face an 86% chance of extinction over the next 20 years. The exact cause for the die-off is unknown, but researchers speculate that a combination of land-use changes and pesticides may be to blame. 

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