Monarch butterflies are perhaps the most well-known butterflies in all of North America – but their future has become uncertain.
Each year, monarchs undertake an epic migration – traveling from the U.S. and Canada to the forests of Mexico for the winter. But Mexico’s National Commission of Natural Protected Areas has reported a 59 percent decline in the population of overwintering monarchs since 2011 – the lowest in two decades. And similar decreases have been reported on the California coast.
Besides ongoing habitat loss due to construction and development, the main threat to monarchs is the loss of milkweed plants throughout their migratory route. Milkweed is the only plant on which monarchs can lay their eggs – but because it tends to sprout up along roads and highways, it is often mowed down by municipal work crews. And homeowners who spot it in their yards often regard it as a nuisance weed.
Milkweed has also proved vulnerable to the increased use of herbicides and to climate change. Drought, wildfires, and record-high temperatures all reduce the nectar that monarch larvae need to survive.
The non-profit organization AdkAction has called on municipalities throughout the Adirondacks to hold off on mowing milkweed for the duration of the summer – until the butterflies begin their migration south.
And for now, there are things we can all do to help. Learn to identify milkweed, refrain from cutting it, and consider planting butterfly gardens that include late-blooming flowers, which can attract and support monarchs’ survival.
**********
Web Links
Royal Descent: Monarch Butterflies Suffer Sharp Drop in Numbers
http://www.scientificamerican.com/article.cfm?id=monarch-butterflies-in-sharp-decline
Photo, taken on October 5, 2012, courtesy of U.S. Fish and Wildlife Service Northeast Region via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.