Where have all the monarch butterflies gone?
An annual count shows the number of orange-and-black butterflies has crashed in the two decades. But there's something you can do to help.
Fri, Mar 15 2013 at 1:45 PM
While the plight of the honeybee has launched countless petitions to save them, including television segments, awareness campaigns, and even a movie, another important member of the ecosystem — one that's actually native to North America — has experienced a dramatic decline in population, a decline that has caused far less hand-wringing by gardeners and do-gooders.
The number of monarch butterflies that arrived at their overwintering location in Mexico dropped 59 percent this year, the lowest level since scientists began keeping records 20 years ago, reports the Associated Press.
This is the third straight year of decline for the butterflies that migrate from Canada and the United States to mountaintop forests in central Mexico. Scientists can't explain why or how these delicate orange-and-black butterflies make the migration, but it takes generations of butterflies crossing two borders to complete.
What's the cause of the monarch butterfly decline?
For years experts speculated that the monarch butterfly decline was due to illegal logging in the Mexican fir forests where they travel every winter, but recent conservation efforts have greatly reduced that threat.
"It is now necessary for the United States and Canada to do their part and protect the butterflies' habitat in their territories," Omar Vidal, the World Wildlife Fund director in Mexico, told the Associated Press.
As with honeybees, experts point to American farmland, which is increasingly planted with genetically modified soybean and corn engineered to withstand herbicide applications. These herbicides are wiping out milkweeds, on which monarch larvae feed, in critical feeding grounds in the American Midwest.
"That habitat is virtually gone. We've lost well over 120 million acres, and probably closer to 150 million acres," says Chip Taylor, director of the conservation group Monarch Watch at the University of Kansas, in an interview with The New York Times.
Last year's drought certainly didn't help the monarchs on their trek north. Texas, one of the first stops for the butterflies after leaving Mexico, had its hottest year on record in 2012.
"The severe drought in Texas and much of the Southwest continues to wreak havoc with the number of monarchs," butterfly tracker Craig Wilson, a senior research associate at Texas A&M University, told USA Today.
This winter's record-low monarch butterfly count should alarm us. While it won't mean a deathblow in the immediate future for one of the world's great migrations, it does make monarchs vulnerable.
How you can help monarch butterflies bounce back
While officials are busy assigning blame for the decline, there is something the rest of us can do that will help boost numbers.
Start by planting milkweeds if you live along the monarch migration path. Monarch Watch has a good list of shrubs, cultivated annuals, perennials and wildflowers that make good nectar sources for butterflies that you can plant to create a butterfly garden.
In particular, create a mud puddle to provide male butterflies with the minerals they need to reproduce. Butterfly Pavilion recommends home gardeners sink a pan into the ground that is filled with equal parts sand and composted manure. If kept moist throughout the growing season, the puddle may become a gathering place for butterflies.
Before placing your fruit scraps into the compost bin, toss the chunks of rotting apples, pears, peaches, and oranges into a mesh bag and hang them from a tree for butterflies.
While there is little we can do about the expansion of farmland destroying feeding grounds for monarchs, we can take small steps that will have a big impact in protecting the monarch migration for generations to come.
Related posts on MNN:
- Want to attract butterflies? First, don't kill the caterpillars
- Butterflies move north as climate warms
Inset photo of wing detail: Burnt Umber/Flickr
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