On December 10th, 2024, the United States Fish and Wildlife Service announced its intention to list monarch butterflies (Danaus plexippus) as “threatened” under the Endangered Species Act. It was just over 50 years ago that infamous president Richard Nixon signed the ESA into law. At the time, The United States Supreme Court deemed the law “the most comprehensive of its type to be enacted by any nation.” On one hand, the law focuses on individual species; on the other, it explicitly protects those species to preserve functioning ecosystems, not just the plants or animals that are under threat.
Since we’re in the 90 day comment period before monarchs would officially be listed, I thought I would publicly offer my thoughts. I couldn’t love the creatures more; they are the subject of my life’s work, and they are an icon of nature. Some have called them the Bambi of the insect world.
Listing monarchs under the ESA would raise awareness, protect habitat for other important species and send a message about how we value and must continue to protect nature. But science and symbolism aren’t always on the same page. And while I support seizing those rare moments of conservation opportunity, we must also remember the bigger picture of conservation without getting lost in the symbolic designation of a single species.
To be clear, in my own research and comprehensive reading of the literature on monarch butterflies, I don’t find any credible evidence that the species is at risk of extinction. In fact, I would call them weedy. Why do I consider monarchs weedy? This species, once called The Wanderer due to its proclivity to get around, has established itself in New Zealand, Australia and southern Spain. As I write this, from the Big Island of Hawaii, I see three monarch butterflies flitting around non-native ornamental milkweeds that have been planted here. I am more than 2,000 miles from the nearest native monarch. Yet all of these locations, and others, are places where milkweed plants, the only host of the monarch butterfly, have also been introduced. So, the wanderer followed and colonized.
If it’s so weedy and won’t go extinct, why should we protect the monarch? First and foremost, their populations have considerably declined in their native North American range over the past 30 plus years. They are a spectacle of nature and they are declining in their homeland. As you hopefully know, they make an unfathomable annual migration of several thousand miles. One generation flies from Texas northwards. Another generation flies to the northeast or the midwestern United States, only to give rise to generations that stay local. Finally, towards the end of summer, the seasons signal the onset of a strategy to orient South and fly to central Mexico. And in Mexico, hundreds of millions of butterflies overwinter in a tiny area, the size of New York City. The number of butterflies at that pinch point in Mexico has declined very substantially. I don’t care about this decline because of extinction risk, but because monarchs are sentinels.
What they have whispered to me, as they taste their way flying along from Canada to Mexico, is that the North American continent is not so healthy. We’ve chopped their natural habitats into tiny fragments, separated by endless interstates and overrun development. Over half of America’s land goes to agricultural uses. Much of this land is degraded and laced with poisons, from pesticides to emissions like sulfur dioxide from burning fossil fuels. Even if these pollutants don’t always kill our monarchs, they surely sicken them. The threats are manifold, and we simply don’t have the societal appetite to really change our ways. Without that appetite, we can at least designate our beautiful monarchs as threatened, acknowledging their decline.
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The monarch will persist, even in North America. You won’t have to go on vacation to see them. As a symbolic measure, listing them could serve as a wakeup call. More likely, it represents wanting our cake and eating it too. And even if protection under this law is correlated with monarch numbers rebounding, we mustn’t celebrate. They are but royal representatives of what most of us want to conserve: functioning ecosystems that provide clean water, pollinators and the beauty of nature that sustains our lives. I urge the US Fish and Wildlife service to designate this species as threatened, but to not forget the bigger picture. Our ecosystem is at risk; the monarch is just a bellwether.
Anurag Agrawal is the James A. Perkins Professor of Environmental Studies in the College of Agriculture and LIfe Sciences. His column Candor and Chlorophyll runs periodically this semester. He can be reached at [email protected].
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