Saving the Eastern Monarch
The Monarch butterfly once numbered in the millions. But with the introduction of Roundup as a standard pesticide in the farming lands in the middle of the country, coupled with climate change impacts and habitat loss, milkweed plants have disappeared and the Monarch’s population has declined dramatically.
According to Xerces Society: In the 1990s, hundreds of millions of monarchs made the epic flight each fall from the northern plains of the U.S. and Canada to sites in the oyamel fir forests in central Mexico, and more than a million monarchs overwintered in forested groves on the California coast. Now, researchers and community scientists estimate that only a fraction of the population remains—a decline of approximately 80% has been seen in central Mexico and a decline of 99% has been seen in coastal California.
A new study at Simon Fraser University in Canada points to the essential role of milkweed plants, the larval food of Monarch caterpillars, in the butterfly’s survival here in the Eastern part of the country. The study, published in Frontiers in Environmental Science, focuses on how to prevent the eastern monarch butterfly from the same fate as the western population, which had "zero overwintering populations, putting them at an all-time low and closer to extinction," according to the study’s co-author Rodrigo Solis-Sosa.
Eastern monarch butterflies overwinter in Mexico from November to March then migrate and reproduce across the U.S. before reaching eastern Canada in late August. Milkweed has declined across the U.S. due to clearing land for agricultural use, GMO crops, herbicides and climate change. While identifying the U.S. midwest as the best place to focus on restoration efforts, given optimal weather and milkweed availability when the monarch butterfly arrives, the team also found that the southern U.S. has a paramount yet somewhat neglected role.
Researchers also found that recommended estimates of between 1.2 and 1.6 billion milkweed stems falls short of supporting butterfly populations-- by 50 to 90 percent. Existing conservation models don't factor in the effects of drought, changes in temperature and the stem's effective usability by the monarch butterflies.
"Monarchs may need at least three billion stems to reach a safe minimum threshold population of six overwintering hectares," says Solis-Sosa. The population once covered the equivalent of 18 hectares over its wintering territory nearly 25 years ago, but that hasn't risen above six over the past decade. The latest measure has dwindled to just 2.3 overwintering hectares.
Communities in Mexico also depend on monarch butterfly ecotourism as an essential part of their livelihoods. "Monarch butterflies also hold a special significance in traditional Mexican culture," says Solis-Sosa. "They arrive in Mexico by November 2--the Day of the Dead--and symbolize the dead souls of loved ones arriving to comfort them through the dark and cold winter season. Losing the monarch butterfly would represent a cultural loss to the Mexican people."
What We Can Do Here to Help the Monarchs
So what can residents in Sherborn and surrounding communities do to help the Monarch? We’re not in the Midwest and Southern migration paths of the Monarch but we are in their essential summer breeding territory. So let’s keep milkweed populations thriving in our town!
May is a great time to look for Common Milkweeds sprouting up in your yard. They often take root in lawns in a sunny spot. If a Common Milkweed pops up in your yard, make sure you don’t mow it down and instead let it grow and seed to make more plants. If it’s happy it may establish an entire colony of handsome, tall plants. Single plants are good but a colony is even more attractive to the adult butterflies, giving them more choices for egg laying and nectaring.
The flowers that bloom in summer are not showy but the aroma is strong, spicy and warm, like an amazing natural aromatherapy, and the blooms attracts bees, beetles and, of course, Monarch butterflies!
You can purchase their ornamental cousins, Swamp Milkweed (Asclepias incarnata) and Butterfly Weed (Asclepias tuberosa) from nurseries and the Garden in the Woods in Framingham, and plant them in your garden. I’ve seen Swamp Milkweeds growing naturally in Sherborn, too. I’ve read that Tropical Milkweed is not an appropriate host plant here in the Northeast, so stick with the native varieties.
Keep an eye out for Pale and Black Swallow-worts, which are invasive plants in the same family, and pull them up the minute you see them. They attract Monarch butterflies but if a female Monarch lays its eggs on the Swallow-wort, the leaves don’t provide an adequate food source for the larvae, becoming a biological trap. Also, they are nasty invasive plants that can take over a lawn or field.
Xerces Society has published a fantastic book, 100 Plants to Feed the Monarch, which lists all the milkweed species across the country that nurture the caterpillars, and equally important, suggests a long list of native plants that supply nectar to the adult butterflies. The book has beautiful photos of all the plants so you can imagine how they’d look in your garden or backyard meadow. You can buy it from Xerces while making a gift to the organization or buy the book alone on Amazon. Many of the native plants they recommend are available at the Garden in the Woods shop in Framingham, which is run by the Native Plant Trust. Their plants are all grown organically without systemic pesticides that can kill pollinators.
If you’re interested in getting involved in the Midwest, or you have relatives there who can help, check out the Mid-America Monarch Conservation Strategy sponsored by the Midwest Association of Fish and Wildlife Agencies. The USDA is also working with farmers to restore milkweed in agricultural settings.
