Gone: Mass Extinction and the Hazards of Earth's Vanishing Biodiversity
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two weeks after leaving big bend, along Interstate 10 in Arizona, I happen to see a flock of big birds lumbering on the reluctant elevator of an early morning thermal—white birds with black flight feathers, afloat with outstretched necks and trailing legs, flapping with a characteristic flick on the upbeat, yodeling. They're whooping cranes, 30 adults and juveniles rearranging themselves into a lopsided V and heading west.
It's a remarkable sight since it represents about 6 percent of the total world population of whoopers. It's also a confusing sight, since at this time of year they should be well east of here en route from Canada to the Texas Gulf Coast...though one of the things I've learned from decades of working with animals in the wild is their ability, with the flip of a wing, to rewrite expectation. But, most of all, it's a poignant sight, these 30 whoopers, the descendants of a breeding population of only 16 birds in 1941. "Because it is a wild, wary, wilderness bird," wrote John K. Terres, longtime editor of Audubon magazine, "it could not stand the intrusion of mankind."
Their decline is an extinction textbook. They suffered the conversion of prairies and wetlands to farms. They were hunted for meat. By 1922, the last known breeding pair in Saskatchewan died, leaving only one winter population in Texas whose summer nesting grounds remained an intractable mystery for most of the 20th century. In 1954, the colony was finally tracked to remote Wood Buffalo National Park in Canada's Northwest Territories, about as far as they could get from human beings without leaving planet Earth.
Since then, the cranes have been rehabilitated in every way we know, as well as in ways we've made up as we went along, forging techniques now considered the blueprint for endangered species recovery. Yet whoopers today number about 500 birds: 350 in the wild, the rest in captivity. They're only marginally less vulnerable than they were in 1941. A bird flu, an oil spill, a hurricane. Seventeen died in the tornadoes that struck Florida in February, highlighting how tenuously this tribe survives.
i spot the whoopers en route to Arizona's Chiricahua Mountains, one of the 40 ranges collectively known as the Sky Islands—a landscape currently at the forefront of endangered species efforts. The Sky Islands are located at the convergence of four great ecoregions: the lower-elevation Sonoran Desert and the higher elevation Chihuahuan Desert, as well as the temperate Rocky Mountains and the subtropical Sierra Madre Occidental, which together funnel life from north and south, introducing pop-up biodiversity through changes in altitude. Some 4,000 plants and half the breeding birds in North America reside here.
The Chiricahuas are a Sky Island range 20 miles wide, 40 miles long, and rising nearly 10,000 feet. Composed of striking pink rock, they're the eroded remains of volcanic ash and pumice that erupted 27 million years ago, since cut by wind and water into whimsical feats of balance the Apaches called the Land of Standing-Up Rocks. The range is dissected by deep drainages that harbor unlikely kaleidoscope forests of sycamore, oak, juniper, pine, cypress, and madrone, alongside yuccas, agaves, chollas, ferns, mushrooms, grasses, and mosses.
It's a botanical mash-up, part mountain, part desert, part grassland. I can hardly take it in, moving fast, on foot, in pursuit of Kim Vacariu, who sets the pace down a trail that crosses and recrosses the flood-tumbled rocks of the South Fork of Cave Creek. He hikes lightly in what amounts to his back yard, telling me stories of the Chiricahua Apache, who, in their last year of existence here, down to only 39 men, women, and children, eluded one-quarter of the U.S. Army by running full speed at night across the desert floors linking the Chiricahuas to other Sky Island refuges.
Vacariu is the western director of the Wildlands Project, the conservation group spearheading the drive to rewild North America—to reconnect remaining wildernesses (parks, refuges, national forests, and local land trust holdings) through corridors, on a continentwide scale. The idea came into being 15 years ago, a hybridization between activism and science, when Earth First founder Dave Foreman teamed with Michael Soulé, professor emeritus at the University of California-Santa Cruz and one of the founding fathers of conservation biology.
Rewilding is bigger, broader, and bolder than humans have thought before. Many conservation biologists believe it's our best hope for arresting the sixth great extinction. E.O. Wilson calls it "mainstream conservation writ large for future generations." Because more of what we've done until now—protecting pretty landscapes, attempts at sustainable development, community-based conservation, and ecosystem management—will not preserve biodiversity through the critical next century. By then, half of all species will be lost, by Wilson's calculation. To save Earth's living membrane, we must put nature's shattered pieces back together. Only megapreserves modeled on a deep scientific understanding of continentwide ecosystem needs hold that promise. "What I have been preparing to say is this," wrote Thoreau more than 150 years ago, "in wildness is the preservation of the world." This, science finally understands.
The Wildlands Project calls for reconnecting wild North America in four broad megalinkages: along the Rocky Mountain spine of the continent from Alaska to Mexico; across the Arctic/boreal from Alaska to Labrador; along the Atlantic via the Appalachians; and along the Pacific via the Sierra Nevada into the Baja Peninsula. Within each megalinkage, core protected areas would be connected by mosaics of public and private lands providing safe passage for wildlife to travel freely. Broad, vegetated overpasses would link wilderness areas split by roads. Private landowners would be enticed to either donate land or adopt policies of good stewardship along critical pathways.
It's a radical vision, one the Wildlands Project expects will take 100 years or more to complete, and one that has won the project a special enmity from those who view environmentalists with suspicion. Yet the core brainchild of the Wildlands Project—that true conservation must happen on an ecosystemwide scale—is now widely accepted. Many conservation organizations are already collaborating on the project, including international players such as Naturalia in Mexico, national heavyweights like Defenders of Wildlife, and regional experts from the Southern Rockies Ecosystem Project to the Grand Canyon Wildlands Council. And Vacariu reports that ranchers are coming round, one town meeting at a time, and that there is interest, if not yet support, from the insurance industry and others who "face the reality of car-wildlife collisions daily."
At its heart, rewilding is based on living with the monster under the bed, since the big scary animals that frightened us in childhood, and still do, are the fierce guardians of biodiversity. Without wolves, wolverines, grizzlies, black bears, mountain lions, and jaguars, wild populations shift toward the herbivores, who proceed to eat plants into extinction, taking birds, bees, reptiles, amphibians, and rodents with them. A tenet of ecology states that the world is green because carnivores eat herbivores. Yet the big carnivores continue to die out because we fear and hunt them and because they need more room than we preserve and connect. Male wolverines, for instance, can possess home ranges of 600 square miles. Translated, the entire state of Rhode Island would have room for only two.
Vacariu leads me to a bend in Cave Creek where clusters of maple trees shed red leaves into the eddies, a place as ephemerally beautiful as a haiku. The scars of flash floods surround us, yet tranquility abides. The first campaign out of the Wildlands Project's starting gate is the Spine of the Continent, along the mountains from Alaska to Mexico, today fractured by roads, logging, oil and gas development, grazing, ski resorts, motorized backcountry recreation, and sprawl.
The spine already contains dozens of core wildlands, including wilderness areas, national parks, national monuments, wildlife refuges, and private holdings. On the map, these scattered fragments look like debris falls from meteorite strikes. Some are already partially buffered by surrounding protected areas such as national forests. But all need interconnecting linkages across public and private lands—farms, ranches, suburbia—to facilitate the travels of big carnivores and the net of biodiversity they tow behind them.
The Wildlands Project has also identified the five most critically endangered wildlife linkages along the spine, each associated with a keystone species. Grizzlies in the lower 48, already pinched at Crowsnest Pass on Highway 3 between Alberta and British Columbia, will be entirely cut off from the bigger gene pool to the north if a larger road is built. Greater sage grouse, Canada lynx, black bears, and jaguars face their own lethal obstacles farther south.
But by far the most endangered wildlife linkage is the borderlands between the United States and Mexico. The Sky Islands straddle this boundary, and some of North America's most threatened wildlife—jaguars, bison, Sonoran pronghorn, Mexican wolves—cross, or need to cross, here in the course of their life travels. Unfortunately for wildlife, Mexican workers cross here too. Of late, Vacariu says, these immigrants have been traveling up the Chiricahuas. Men, women, and children, running at night, one-gallon water jugs in hand.
The problem for wildlife is not so much the intrusions of illegal Mexican workers but the 700-mile border fence proposed to keep them out. From an ecological perspective, it will sever the spine at the lumbar, paralyzing the lower continent.
Photo: Richard Ross
