Farming and land clearing did reduce the abundance of some milkweeds, such as those that live in prairies. But only in recent decades have human activities become a clear threat to monarch butterflies. During that period, American farms consolidated, and farmers began planting from fencerow to fencerow, applying powerful insecticides and adopting genetically engineered crops that allow for mass herbicide spraying, which has reduced monarchs’ breeding habitat. Logging in the Mexican forests has cut into monarchs’ winter habitat. Warming weather, a parasite that infects monarchs that overwinter in the U.S. South, and collisions with cars on highways are also taking a toll. Choose almost any large-scale environmental concern—climate change, agricultural chemicals, GMOs, deforestation, suburban development—and the beleaguered monarch seems to embody it.

Nothing, perhaps, is more natural than wanting to save nature. Nearly everyone, in one way or another, cherishes and wants to preserve a remembered or mythologized environment that seems less impacted and more whole.

But most of us—and I want to be clear that I include myself—are confused about what the actual nature is that we want to protect. Humanity’s environmental footprint has been so heavy for so long, and we know so little about the life around us—much less about the myriad complex interactions that sustain this life—that we may have little sense of what was here before us, and what is here because we are here. Often we seek to preserve a version of nature that is already profoundly altered and simplified.

Many of us have grown so used to the tiger-colored insects casually flitting through our fields and gardens that the thought of their absence is almost too much to bear. So rather than reforest places that were once forested, conservation-minded people plant yards and parks with milkweed and nectar-producing plants, seeking to attract monarchs.

That in itself is surely harmless, and plants that attract monarchs also benefit many others. (More than 450 insects are known to eat common milkweed.) There is danger, however, in pinning so many hopes on one charismatic species. This is obviously not how nature operates. It goes instead for strength in numbers and diversity; it hedges its evolutionary bets with a profusion of forms.

The sheer numbers can defy belief. According to the Biota of North America Program, Prince George’s County, where I live, is a national hot spot for plant biodiversity. Somehow, even in this highly populated and developed suburban jurisdiction, with a several-century history of deforestation and farming, more than 1,200 native plants have been documented. Every one of those plants harbors its own retinue of native insects, which feed everything else.

The closer you look, the more astounding it can get. The entomologist Douglas Tallamy has found 879 species of moths alone on his property. And there are probably many more out there. “I can still go out in my backyard and find an undescribed species without a whole lot of trouble,” he told an audience at the Audubon Naturalist Society in Chevy Chase, Maryland, in December. Tallamy does not live in a remote nature preserve; he lives on a fairly modest 10-acre lot in the Pennsylvania exurbs, where he has judiciously cultivated insect-harboring native plants.