As a young child, I remember blissfully chasing monarch butterflies around my neighbourhood. They were around copiously and their existence was common. This summer while walking through the woods, I saw a monarch butterfly and my heart leapt with excitement. That’s when I realized how long it had been since I had seen these beautiful creatures.
Monarch butterflies have survived asteroid impacts and other ecological catastrophes. Every November, they arrive in the mountain forest of central Mexico to hibernate for the winter, making their two month journey is the second largest of all insect species on Earth.
Recently, scientists have found a disturbing trend: the number of butterflies migrating to Mexico has dropped dramatically. Research from the WWF-Telcel Alliance and the Monarch Butterfly Biosphere Reserve Office of Mexico showed a 43.7% decline in the total amount of forestland occupied by monarchs in and near Mexico’s Monarch Butterfly Biosphere Reserve.
So why are monarch populations dropping?
Lincoln Brower, a biology professor at Sweet Briar College who has studied the monarch migrations for decades sites three reasons: deforestation In Mexico, recent bouts of severe weather, and herbicide based agriculture which is destroying Milkweed –the monarch’s primary food source. According to Brower, Milkweed destruction has the most devastating impact on monarch populations. Monarch butterflies only lay their eggs on Milkweed, while caterpillars rely on the plant as its sole food source.
Milkweed crops that have been planted throughout the Midwest have been genetically modified to be resistant to the powerful herbicide Roundup. These crops are planted in grassland ecosystems of the United States (US) where monarchs do most of their breeding and where large amount of Milkweed plants reside. There are about 108 species of Milkweed plants in the United States, and the monarch migration evolved in order to synchronize with this evolution of Milkweed flora.
However, because of the extensive herbicide use in the US it calls all Milkweed seedlings and emergent plants. A paper written by John Pleasants of the University of Iowa and Karen Oberhauser of the University of Minnesota estimated that 60 percent of milkweed species has been eliminated from grassland ecosystems of the US.
Why should we care about the decline of monarch butterflies?
There is a large aesthetic aspect that resonates with butterfly aficionados. According to Brower, a decline in monarchs is “just like going to the museum and pulling a rare painting off the wall and destroying it.”
Their charisma helps in the classroom, where monarch butterflies are used as an educational tool for teaching population dynamics and migrations.
And of course, declining populations due to human interventions should warrant care and mitigation. As Brower notes, their decline is a signal that something is going awry ecologically. “I think the monarch is the canary in the coal mine telling us that things are beginning to go really wrong, when you can take a widespread migration of this sort and completely dismantle it as a result of human activity.”
What can we do to help monarch populations?
Monarch Watch is a US organization that works to preserve monarch butterflies and suggests that homeowners plant Milkweed in their gardens. Although many gardeners may cut milkweed down due to its unpleasant smell or weed-like resemblance, monarch butterflies need Milkweed to survive - even if they are aesthetically unpleasant.
Many organizations and environmentalists are also working to promote good forest management and agricultural practices as well. WWF helped to create the Monarch Butterfly Conservation Fund, which works to benefit communities who are successful in eliminating illegal logging in the area. The Michoacan Reforestation and Habitat Protection Fund is a project created to balance the needs of Monarchs with the needs of people who live where monarchs spend their winters. The Monarch Butterfly Sanctuary Foundation gives financial and scientific support for preserving the grounds of eastern Monarch butterflies.
There’s hope for the monarchs, as scientists are confident that these butterflies can recover. Although they are very resilient (like many insects species), they can only bounce back in the right conditions and will require mitigation to succeed.
Monarch butterflies may very well qualify as one of the most beautiful and majestic butterflies on the planet today. The childhood moments I hold with monarchs are special to me, and with proper response, I know that future generations will cherish similar memories.