National Geographic : 2016 May
104 national geographic • may 2016 that lasted from 1934 to 1967. Whipsaw changes. During that long elk-reduction regime, park rangers shot 13,753 elk from the north- ern herd, private hunters killed 41,400 when the animals migrated out of the park, and almost 7,000 were trapped and shipped away to forests and zoos elsewhere. In the late 1960s the park superintendent and his chief biologist, influenced by the Leopold Report and some fashionable new thinking in ecology, embraced a policy called nat- ural regulation. But what were the limits of “natural” in the service of “regulation”? Was it more natural to let elk starve than to hunt them? Was it more natural to haze bison back into Yellowstone with helicopters, trucks, and rangers on horseback than to ship them to slaughter so that the meat could go to Native American tribes? Hard to say. That fancy phrase “natural regulation” served to codify in two words—but not solve—the paradox of the cultivated wild. As for wolves, reintroducing them was a bold act of management that did restore some “natural” conditions. But how far do those con- ditions ramify? Attitudes toward the wolf are more bitterly polarized and complex than those around any other creature in Yellowstone. Beyond the wolf-haters-versus-wolf-lovers tussle, scientists disagree about how and to what degree wolves are reshaping the Yellowstone ecosystem. Do they reduce reproductive success among elk simply by creating a landscape of fear, wherein the great bulls and cows are too nervous to eat and procreate? Have wolves killed enough elk to curtail elk browsing on aspen and willow shoots? Has that reduced browsing allowed aspen and willow stands in Yellowstone to recover and renew themselves for the first time in decades? Has such aspen and willow recovery enabled the return of beavers and songbirds? Or is reality a little more intricate? Some scientists and wolf advocates tell this story in happy, simplistic terms. “But it’s an unproven theory that gets undue attention,” Middleton said, “in the quest to have wolves shine rainbows out of their asses.” Middleton is an improbable fit for the role of Wyoming elk ma- ven: a South Carolina kid, a graduate of the Yale School of Forestry and Environmental Studies, who came west nine years ago, having landed work on a study of elk-wolf interactions commissioned by Wyoming Game and Fish. After arriving in Cody to meet his new collaborator, he admitted that he’d never seen a wolf or an elk. But he learned fast, and he loved the mountains. He put GPS collars on elk, clarifying poorly understood patterns in their movements between summer and winter ranges. He collated similar data from other researchers and made eye-opening digital maps. Look where these animals go. “Most of Yellowstone’s elk,” he said later, “are not in Yellowstone for most of the year.” They’re off the plateau, down on winter range, where the snow isn’t so deep and the temperatures aren’t so brutal, largely on private ranches. By this time Middleton had a Ph.D. from the University of Wyoming and a postdoc position back at Yale. His hair was long, his speech was slow and considered, his brow scrinched when he pondered something carefully. Within Great Migrations As many as 25,000 elk spend summers grazing in the region’s high pastures, but fewer than 5,000 stay for the winter. The herds shown at right make up most of the elk that roam in and out of the park, representing a vital shift of resources. The elk provide food for predators such as wolves, and their own feeding affects soil fertility, the diversity of plants, and the behavior of other grazers competing for grass.