N THE MIDDLE OF THE LAST CENTURY, before President Lyndon B. Johnson signed the Wilderness Act, a debate raged among American conservationists over wildlife in national parks. A. Starker Leopold, son of the pioneering ecologist Aldo Leopold, had been tasked with developing a wildlife management plan for the parks and concluded that the National Park Service ought to try to re-create "a reasonable illusion of primitive America." Preservationist Howard Zahniser, the primary author of the Wilderness Act, disagreed, arguing that Leopold's approach posed "a serious threat to the wilderness within the national park system and indeed to the wilderness concept itself." Humans should not try to manipulate wilderness, Zahniser wrote. We should be "guardians, not gardeners."
Zahniser's position eventually won out and was incorporated into the Wilderness Act. But that didn't settle the debate, which continues to this day. The temptation to tinker is strong—especially now, in an era of rapid climate change—and sometimes irresistible. Case in point: the spring 2018 decision by the National Park Service to reintroduce up to 30 wolves into Michigan's Isle Royale National Park over a five-year span so the population there can survive.