It’s one of nature’s most incredible sights: Millions of monarch butterflies, clustered together across the tree line, moving their wings in near unison. As the temperature warms, the butterflies take flight, cascading through the forest in a sea of orange, white and black. No wonder these swarms are, evocatively, also called kaleidoscopes.
Every year, monarch butterflies undertake the arduous 3,000-mile journey from the Great Lakes to winter in California and Mexico. They have followed this migratory path for centuries, pollinating flowers across the continent and inspiring awe in generations of Americans. Now, these creatures — an indelible part of many childhood memories — are under threat.
In July, the International Union for Conservation of Nature (IUCN) placed the species on its “Red List,” designating it “endangered.” Estimates suggest that the monarch population has declined between 22 percent and 72 percent in the past decade alone; the population in the west has shrunk by an estimated 99.9 percent since the 1980s.
Some variation in butterfly numbers is normal. But looking at 10-year averages, it is clear the population is fluctuating around a mean well below the range of the 1990s and 2000s. Experts attribute the decline to habitat loss and climate change. As North American farms increasingly use herbicides associated with genetically modified corn and soybeans, milkweed plants — the sole diet of monarch caterpillars — are disappearing. That, coupled with urbanization and the extreme weather events of the past few years, has imperiled monarch breeding.
The U.S. Fish and Wildlife Service spent years assessing whether it should list monarchs as threatened or endangered under the Endangered Species Act. It eventually decided that, though monarchs met the criteria for protection, many other species were at higher risk and had greater need of federal intervention. It is a sad reflection on the state of the world that so many species merit this designation, with limited resources on hand to help them.
The recent IUCN classification does not trigger any legal or regulatory responses. Still, the news should drive attention to the pressures facing monarchs — and other flora and fauna affected by deforestation, global warming and other threats to biodiversity. This includes creatures that are less recognizable and beloved. A 2019 scientific review found that a third of insect species were endangered, with a rate of extinction eight times higher than reptiles, birds and mammals. Data suggests that the total mass of insects worldwide is declining by more than 2 percent annually.
PLANTING MORE milkweed and nectar-producing flowers could help monarchs. But, as with all forms of conservation, individual efforts can only do so much. Policies that address climate change, maintain protected lands and curb cultivation on marginal land with little commercial value would have far greater impact — for butterflies and many other forms of wildlife.
Our natural world is full of marvels. We should do what we can to preserve them for future generations — and ensure our planet’s ecosystems can survive and thrive.
