Eastern Monarch butterflies at risk of extinction unless numbers increase

http://www.eurekalert.org/pub_releases/2016-03/usgs-emb032116.php

PUBLIC RELEASE: 21-MAR-2016
Eastern Monarch butterflies at risk of extinction unless numbers increase
UNITED STATES GEOLOGICAL SURVEY

Long-term declines in the overwintering Eastern population of North American monarch butterflies are significantly increasing their likelihood of becoming extinct over the next two decades, according to Scripps Institution of Oceanography at UC San Diego and U.S. Geological Survey research published today.

The new study, available in the journal Scientific Reports, found that the Eastern migratory monarch population declined by 84 percent from the winter of 1996-1997 to the winter of 2014-2015. Using this information, the study demonstrated that there is a substantial chance -- 11 to 57 percent -- of quasi-extinction over the next 20 years. A quasi-extinct population is one with so few remaining individuals left that recovery is impossible. While the remaining individuals may survive for a short time, the population as a whole will inevitably go extinct.

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"Previously published research suggested that the most effective way to increase monarch numbers is to focus on the restoration of their breeding habitat," said USGS scientist Darius Semmens, a coauthor of the report. "Over the previous two winters, Eastern monarch populations were very low, indicating a higher risk of losing the species. If their numbers continue to grow, as they did this year, the risk will decrease."