As the sun warms the morning air, bundles of brown leaves slowly come to life. Soon, orange fairies start their delicate dance — flitting through the shady canopy, landing on passersby and dotting the sky. In winter, the fir forests in central Mexico transform with the arrival of millions of monarch butterflies. Once described as “the personification of happiness,” sadly those masses of monarchs are slipping away.
Along with many other insects, monarchs are disappearing. Their migratory populations declined 80 to 99 percent over the past few decades. While the migratory monarch was listed as endangered on the International Union for Conservation of Nature's Red List of Threatened Species in 2022, the U.S. Endangered Species Act has not offered them any formal protection. With federal action lacking, it's up to citizens and corporations to help America’s insect.
The benefits of monarch butterflies
Monarch butterflies and other pollinators provide us with a variety of benefits, so sharp declines in their populations impact us negatively.
“We used to have hundreds of millions of monarchs, especially in the eastern United States, and tens of millions of them in the West,” said Scott Black, executive director of the Xerces Society for Invertebrate Conservation. “Monarchs recycle nutrients by eating their host plants, and they’re food for a huge variety of animals. They're likely really important from an ecosystem functioning point of view.”
Monarchs are also deeply embedded in our culture. We raise them in classrooms, visit butterfly gardens, and celebrate them in festivals, myths and legends. And we value this cultural importance a lot. Americans are willing to spend a combined $4.7 billion to $6.6 billion for monarch conservation through donations and money spent growing monarch-friendly plants, according to a survey published by the Society for Conservation Biology.
The appeal of monarch butterflies also draws tens of thousands of tourists to their overwintering grounds in Mexico and coastal California, generating income for local communities.
Threats to monarchs
Nonetheless, tackling the monarch’s decline is challenging. Weighing less than a paperclip, they can migrate an astounding 3,000 miles each year. This mobility means habitat spanning three borders needs to be protected.
In the U.S. and Canada, many breeding areas used to be covered with milkweed and flowers. Milkweed is the exclusive food for monarch caterpillars, while flowers provide nectar for adults. Unfortunately, many of those areas were converted for agricultural use. The widespread use of herbicides and genetically modified crops has further reduced milkweed abundance.
“The use of highly toxic insecticides is likely linked to monarch declines,” Black said. "Pesticides are used ubiquitously in agriculture and for things like mosquito management in some natural areas. They're also used in the quest for the perfect lawn and the perfect road. In two studies we’ve done with the University of Nevada Reno, wherever we test, we find residues of pesticides in milkweeds. About a third of them would have likely been harmful to monarchs who are eating them. And that's a real problem.”
In addition to natural areas, milkweed from nurseries can also contain pesticides, according to a study published in the journal Biological Conservation. In fact, milkweed marketed as wildlife-friendly were almost twice as likely to contain at least one pesticide at levels that were potentially harmful.
Other prominent threats to monarch butterflies include the loss of overwintering areas, climate change, invasive species and disease.
Plans for monarch conservation
Despite that bleak picture, reversing the monarch population decline is achievable. “In some ways, it’s relatively simple,” Black said. “We have to provide what these animals eat. In the case of monarchs, their host plant is milkweed — having a place to lay their eggs and for the young to grow is vital. But when it comes to monarchs, as well as other pollinators, we need to go beyond milkweed. Monarchs are strong flyers, and they use a lot of flowering resources for nectar to fuel flight, mating and egg-laying. So, we need milkweed and mostly native flowers that monarchs and other pollinators can use.”
Fortunately, detailed plans exist to do just that. The Monarch Conservation Science Partnership has a goal to plant at least 1.3 billion stems of milkweed, particularly in the North Central region of the U.S. And the Monarch Joint Venture aims to restore 7 million acres of pollinator-friendly habitat nationally, including 50,000 acres in California’s Central Valley and foothills.
In addition, a consortium of midwestern states and federal, private and non-governmental partners are working to implement the Mid-America Monarch Conservation Strategy. This ambitious plan aims to reverse the monarch population decline by planting milkweed and flowers across the landscape east of the Rocky Mountains.
What can you do for monarch butterflies?
For companies and individuals interested in chipping in, there are a plethora of ways to help.
One option is to plant a pollinator garden in your yard or company’s property. Schools, 4H clubs and scout troops can receive seeds for pollinator gardens through the Save Our Monarchs Pollinator Garden Program. The Xerces Society also has guides for finding suitable milkweed and flowers according to your location and a tool to locate milkweed seeds. But make sure to avoid tropical milkweed, which can be harmful to monarchs.
In an example of environmental responsibility, Google established numerous pollinator gardens across its California campuses. After planting 4,000 milkweeds, the company said sightings of caterpillars are 10 times greater in its gardens compared to control plots. It also provided support to organizations protecting monarch butterflies and their habitat like the Xerces Society and Peninsula Open Space Trust, and gave a grant to the city of Mountain View in the Bay Area to create pollinator habitat.
Another opportunity for monarch conservation exists in roadsides, highways, paths and electric lines. The Rights-of-Way as Habitat Working Group brings the transportation and energy industries together to create monarch habitats across 48 states. The organization encourages brush removal, mowing and seeding strategies that support monarch habitats. Interested energy and transportation companies can join this project until late 2024.
Some companies are going a step further and changing their supply chains to source produce and food grown in a monarch-friendly manner, Black said. Moving toward integrated pest management and reducing pesticides in agriculture, cities and lawns are also big steps in the right direction.
The monarch butterfly has flitted dangerously close to extinction. But there’s still time, and plenty we can do, to save this charming bug.
Image credit: Joshua J. Cotten/Unsplash
Ruscena Wiederholt is a science writer based in South Florida with a background in biology and ecology. She regularly writes pieces on climate change, sustainability and the environment. When not glued to her laptop, she likes traveling, dancing and doing anything outdoors.