One summer day not long ago, I rose before dawn and drove into Yellowstone National Park from the east, stopping at the broad Lamar Valley and hiking a few hundred feet up from the road to a narrow, flat ridge. It was chilly, and light was just beginning to leak into the sky, but there were already dozens - maybe hundreds - of people standing there, most next to spotting scopes mounted on elaborate tripods. They were staring out across the valley at a pack of recently reintroduced wolves, which on the broad plain before them were carrying out their ancient role: If an elk or a moose slipped up and let down its guard, the chase was on. This didn't happen often; it wasn't like the half-hourly geyser down the road at Old Faithful. Most of the time, people were looking at their laminated wolf-spotting cards and radioing each other with information like "Number 493 is peeing in the woods." But there was a cloud of ravens over yesterday's carcass, and apparently a grizzly bear had been by to visit it as well - nature was working the way nature was supposed to work.
Bill McKibben is a scholar in residence at Middlebury College, the author most recently of "The Bill McKibben Reader," and co-founder of 350.org.
And the way it isn't working most places anymore. "Where the Wild Things Were," William Stolzenburg's remarkably engaging book, is an account of how predators have been hunted and squeezed out of most of the human landscape, and about what that has meant for the rest of our planet's biology. Nothing good being the short answer.
Not all the predators Stolzenburg discusses seem to us particularly fierce. Indeed, the story of how science came to understand the crucial role of these top carnivores begins with the . . . starfish. He recounts how a graduate student in the mid-1960s, Robert Paine, would month after month toss all the starfish out of one tidal pool while leaving them in the one nearby. And what happened? "Where the predator . . . went missing, its main prey, a big dark mussel named Mytilus californianus, flourished spectacularly. Within a year, Mytilus had crowded half the other species off the rock, with the survivors hanging on by their figurative fingertips. In time, only a stark monoculture of mussels would remain. . . . Paine had triggered the collapse of his miniature ecosystem."
Stolzenburg describes astonished scientists learning the same lesson about the sea otters that were needed to eat the sea urchins that would otherwise eat the great Pacific kelp forests - and all kinds of whales that were needed to feed the orcas that would otherwise dine on the sea otters. Eventually, haltingly, almost in disbelief, a new ecological paradigm emerged: Though often few in numbers, predators were "keystone species." "Remove them from the archway of life and the whole structure comes crashing down."
Across the landscape, of course, that's just what's happened. If you go to the Amazon, you'll find many patches of jungle devoid of the expected abundance of birds. Why? Because the forest has been too fragmented for the jaguar to survive, and in the absence of the jaguar the number of small mammals like coatimundis has mushroomed, and they vacuum the eggs of ground-nesting species off the forest floor before they have a chance to hatch.
In our neck of the woods, of course, the great overrunning animal is the white-tailed deer. Following the lead of Richard Nelson in his groundbreaking book "Heart and Blood," Stolzenburg shows how the systematic removal of wolves and other predators has led to an almost unbelievable overpopulation of deer. Game-management laws designed to make sure that hunters had lots of bucks to kill have resulted in populations 10 times as large as nature intended. And the results are everywhere: Many species of orchids and wildflowers are driven to extinction, thousands of cars crash into thousands of deer, and plagues that depend on the deer as a host spread wildly. Want to fight Lyme disease? A wolf or a mountain lion would be your best ally.
The great example comes from Yellowstone, where in 1926 park managers finished the job of trapping or shooting the last wolves, leaving the park "wolfless for perhaps the first time in the 12,000 years since Canis lupus had trotted in behind the retreating front of the Pleistocene glaciers." Chaos soon ensued. Elk numbers soared - and, with nothing to fear, elk could eat their way slowly across the park, browsing down young trees and eroding stream banks. Before long, park managers were having to work as, essentially, wolves, culling out "excess" elk. Ditto with bison and other species - a wilderness became an overgrazed pasture.
In the early 1970s, though, a Congress that would seem by current-day standards almost unimaginably enlightened passed the Endangered Species Act, and slowly the wheels were set in motion. Two decades later, in 1995, eight wolves imported from Canada were released into the great park, and (in the incredibly heartening climax to this book) chaos began almost immediately to retreat. Elk suddenly had to watch their step - they couldn't linger by the stream bank chewing down the willow or they'd end up ex-elk. Within a year or two, biologists were marveling at the sudden regrowth of these riverside forests, "trees taking root, sloughing banks taking hold, shade spreading from the flourishing groves over the water's edge," fish returning to the sheltered shallows, warblers to the willows, on and on. All in all, "the West's hoof-beaten oases [were] reborn."
It's long been hard to imagine humans allowing the return of the top predators they worked so hard to extinguish - there's still that Little Red Riding Hood shiver down too many spines. But the best news from the Yellowstone experiment is how popular it's been: Wolves are the new charismatic draw. I left that ridge on the edge of the Lamar Valley in late afternoon and drove to the nearest little town on the park border for dinner. This was a town where wary locals had fought to keep the wolf out - but now every motel room was full of wolf-watchers, every gift shop full of wolf shot glasses and wolf tea towels. Maybe it will turn out to be the place where the tide turned
Bill McKibben is a scholar in residence at Middlebury College, the author most recently of "The Bill McKibben Reader," and co-founder of 350.org. |
