As planes take off at an Army National Guard airfield in Concord, New Hampshire, a tiny, delicate life form exists that’s arguably more reliant on the U.S. military than the soldiers are themselves. Small green caterpillars, barely distinguishable from the leaves they feed on, are the next generation of the Karner Blue butterfly, an insect that landed on the Endangered Species List in 1992.
Twenty-five years ago, Cheryl Schultz—now a conservation biologist at Washington State University, Vancouver—partnered in a study of the Fender’s Blue butterfly, a relative of the Karner Blue that was believed to be extinct until small populations were rediscovered in 1989.
For the Fender’s Blue, a controversial approach using fire in the butterflies’ habitat is working, and scientists want to determine whether the same methods will work for the Karner Blue.
Like Karner Blues, Fender’s Blue larvae dine solely on lupine plants. Maintaining these habitats is challenging. If left alone, grasslands grow into shrub lands or forests that choke out low-growing lupines. And even though nature has its own system for preserving grasslands—modern day humans have essentially wrecked that system by either taking over prairie lands entirely or corralling the animals and small fires that keep these areas intact.
Controlled burns could help maintain grasslands, but they also introduce a conundrum: Use fire and some endangered larvae also go up in flames. But avoid fire and grasslands collapse—taking the butterflies, too.
Since those early test fires at Baskett Slough, Fender’s Blue populations have increased at least nine-fold, possibly more. There are currently an estimated 14,000 to 28,000 Fender’s Blues flitting between lupine plants, Schultz says—a population size that’s large enough to give conservationists hope that the species will survive.
“Here’s a story where we’ve turned it around, but that’s not the usual story,” she says. “Many of our butterflies are sharply in decline, and not just the rare ones.”