Ten years later, Waller and Alverson were back in print with the same warning in sterner tones, loaded with reams of more damning evidence of a situation inexcusably worsening. Conducting their own surveys throughout the hemlock and cedar woods of northern Wisconsin, they found aging trees and understories barren of seedlings, the forests slowly dying. They set up fences to exclude the deer and watched those areas sprout jungles while outside remained stubbled pasture. They cited a study listing ninety-eight species of rare plants of concern being devoured by deer. Once they started looking for the deer’s impacts, they found them everywhere.
One of the more poignant images came from a rare stand of virgin forest in the Allegheny Plateau of northwest Pennsylvania. Heart’s Content National Forest Scenic Area was a 120-acre grove of hemlocks and white pine—some of them four centuries old—a tiny island of giant trees surrounded by adolescent stands of cropped timber. Heart’s Content was a state preserve—no logging, no hunting, no tampering with nature; a supposed port in the storm—yet the bastion had come to resemble more the battlefield. In 1929, a prominent ecologist named H. J. Lutz had surveyed the plants of Heart’s Content. By the mid-’80s, half of the tree species recorded by Lutz were declared missing. A decade later, another survey tallied upward of 80 percent of the understory flowers missing as well. The forest floor had been nearly swallowed in a sea of hay-scented ferns—one of the few plants no white-tailed deer would touch. Heart’s Content, in all its purported purity, had become a graveyard of towering tombstones waiting to topple.
It took an extreme bit of maneuvering for an edible plant to find refuge in the modern forests of Pennsylvania. Thomas Rooney, the young ecologist who had documented the understory decay of Heart’s Content, had noticed in a nearby forest the ground cover increasingly sparse of one of its most previously common wildflowers, a species of deer candy called the Canada lily. Rooney soon discovered, however, he could still find rich pockets of the lilies, if he was willing to climb for them. The last of the lilies had taken refuge atop boulders, upward of fifty feet above the ground.
Rooney soon thereafter came to study under Waller at the University of Wisconsin, and the two set about charting a comprehensive reckoning of the forests’ demise. They began on campus, in a storeroom of old filing cabinets housing the notes of the eminent botanist John Curtis. In preparing his 1959 classic, The Vegetation of Wisconsin, Curtis had carried out the Herculean task of systematically canvassing the entire state for its plant communities. For Waller and Rooney, Curtis’s notes became their Rosetta stone.
Retracing Curtis’s steps, Waller and Rooney, along with colleagues Shannon Wiegmann and David Rogers, chronicled fifty years of change in the Wisconsin flora. “Curtis provided us a much richer picture of what’s going on across the landscape,” said Waller. “And it was a disturbing picture.”
Across the forests of northern Wisconsin, a fifth of the understory’s native species had gone missing since the surveys of Curtis. But the percentages only began to describe the damage. Habitat generalists had prospered, and habitat specialists had declined. Or by Waller’s analogy, “Dandelions are nice, and my daughter likes to pick them. But it’s like junk food—you don’t want to see it or eat it all the time.” The impoverished deer forests of northern Wisconsin—in a trend that echoed across the American East—had by the latest measures become botanical strip malls, monotonous repetitions of deer-proof weeds, sprawling in the wake of the herds.
Haida Gwai
Waller and his colleagues could only speculate beyond their botany to the animals whose fates they suspected were intimately entwined with the failing forests. It was especially worrisome that the hardest-hit flowers—the trilliums and lilies and lady’s slippers, with their conspicuous blooms and ice-cream appeal to whitetails—were also those most heavily reliant on insects to carry their pollen, and birds and mammals to disperse their seeds. It remained to be seen how much the animals would in turn miss their flowers.
As it happened, a French ecologist named Jean-Louis Martin was already on the case, albeit on the far side of the continent in a temperate rainforest off the coast of British Columbia. In 1993, Martin had first come to the forests of Haida Gwai—an archipelago of some 350 islands clustered fifty miles from the Canadian mainland—with some basic questions on birds and the theory of island biogeography. The theory is a sacred formula, proposed in 1963 by the eminent ecologists Robert H. MacArthur and Edward O. Wilson to explain why small and distant islands tend to hold fewer species than others. Leaving the larger relevance of island biogeography for a later discussion, the salient observation here involves Martin’s arrival on Haida Gwai, where he immediately witnessed the sacred theory violated. Touring dozens of islands big and small, Martin found the most birds—oddly enough—on the smallest, most remote islands. It was soon plain to see why. The forests of the little islands were verdant jungles compared with the moss-carpeted parks of the bigger islands. The little islands were thick with bird habitat. They were also, most conspicuously, the only islands free of deer.
For ten thousand years, the forests of Haida Gwai had evolved free of browsing deer. Within the past one hundred years, mainlanders loosed some black-tailed deer on the islands and inadvertently began an untended experiment in the ecology of overabundance.
Freed from the wolves, bears, mountain lions, and hunting humans otherwise prowling the mainland, the blacktails found life especially plush on Haida Gwai. As each little Eden got a bit too crowded, with blacktail densities approaching fifty per square mile, a deer or two would swim to the next virgin paradise beckoning across the channel, and so forth, until they’d colonized all but a handful of Haida Gwai’s islands.
Martin’s team documented not only the demise of Haida Gwai’s understory, but also the birds and insects that went with it. Islands browsed for more than fifty years had lost up to three of every four species of their songbirds. Insect species plummeted sixfold. Many of them were pollinators, raising the possibility that if the deer hadn’t undone Haida Gwai’s understory, sterility might have. The undoing of Haida Gwai caused the researchers to wonder whether deer might be to blame for the broader ongoing collapses of North America’s migrant songbirds and pollinating insects.
Perhaps more than any numerical effect the missing wolves might have had on the deer was their psychological impact. In this land of no predators, the deer grazed as boldly as bulls in summer pasture. Two days after setting up camp, Martin’s crew had their subjects eating out of their hands. “For me it was sort of a major lightbulb which came on,” said Martin. “Suddenly what I realized working there [is] that carnivores are mainly not animals which eat prey but which change the behavior of prey.” And such a change could trigger biological tremors to the base of the food chain.
“We can now say,” Martin continued, “that limiting predators has costs—costs to forestry, and costs to wildlife. If you want to protect land without wolves, you risk losing birds, plants, et cetera. Wolves can thus be management tools. That may sound shocking, but the more one examines our work, the more we can say that this could be a solution, the only solution in some areas, to the problem caused by overabundance of deer.”
Out of Wisconsin
The most striking feature of such revelations as Martin’s and Waller’s were their ubiquity. In the mid-1990s, more than forty biologists and wildlife historians gathered for a symposium in Washington, D.C., with deer stories of their own. The result was a book, The Science of Overabundance, which ran 402 pages long.
William McShea, the lead editor and organizer of Overabundance, had been charting his own slow-moving catastrophe in the Shenandoah Mountains of Virginia. It wasn’t just oak seedlings taking a beating in McShea’s plots. Gray squirrels, flying squirrels, chipmunks, and a host of small mammals of the Blue Ridge surged back wherever McShea fenced the deer out. With the understories also went the birds. McShea could confidently predict the disappearance of certain songbirds by the amount of time the deer were a
llowed to overrun the birds’ habitat.
Researchers in the Alleghenies of northwestern Pennsylvania found likewise. Where the deer surpassed twenty per square mile, the bird diversity dropped by almost a third. Songbirds like the indigo bunting, least flycatcher, eastern wood peewee, yellow-billed cuckoo, and cerulean warbler just disappeared.
In places, even the predators were no longer safe. Anticosti Island, off the coast of Quebec, had once been famously thick in black bears, fattening themselves off huge crops of gooseberries and currants. Within one hundred years of the white-tailed deer’s introduction, there were some 150,000 whitetails on Anticosti, and no more berries. No more berries, no more bears. Remarked Anticosti’s researcher, Steeve Côté, “To my knowledge, this is the first evidence of what appears to be the indirect extirpation of an abundant large carnivore by an introduced herbivore.”
Time and again, the heaviest damages visited forests where the carnivores were gone, the hunters had been barred, and the only remaining predator was the automobile. It was a situation that happened to describe the charter of most national parks. In the Big Meadows wetland of Shenandoah National Park, a herd of deer counted at densities of 150 to 200 per square mile, and fattened on campers’ Cheetos and potato chips, had the park biologists scrambling to rescue what was left of a rare plant community found nowhere else on Earth. Said Shenandoah wildlife biologist Rolf Gubler, “We’ve created a monster.”
Cades Cove in Tennessee, population epicenter of both tourists and deer of the Great Smoky Mountains National Park, receives more than two million visitors each year, few of whom have any idea what they’re missing. In the 1940s, when the park was established, Cades Cove was known for its huge displays of trillium and spring wildflowers. Modern botanists are hard-pressed to find trilliums there now. Forty-six species of wildflowers recorded in Cades Cove in 1970 were gone by 2004, all of them relished by white-tailed deer.
Fence and Fortress
Hidden deep in the Monongahela National Forest of West Virginia, in an otherwise undistinguished hollow (for discretion’s purpose, heretofore called the Hollow), stands what might represent the future of rare orchid conservation in America. There, one of the state’s last two patches of Cypripedium reginae, the showy lady’s slipper orchid, grows in what amounts to a terrestrial shark cage, surrounded as they are by an eight-foot-tall deer fence.
The showy lady’s slipper orchid is one of the biggest, most extraordinary members of what many aficionados consider the most alluring family of flowering plants. With striking white and pink blossoms atop stems reaching to the thighs, the showy lady’s slipper is the queen of North American orchids. It is a rather widely but precariously distributed orchid, once found more commonly throughout the northeastern United States but lately rare and disappearing at worrisome rates in its southernmost locations. When orchid specialist Kathy Gregg from West Virginia Wesleyan College began visiting the lady’s slippers of the Hollow, she discovered the population in the midst of a free fall. In 1987, Gregg counted 650 orchid stems in the little clearing. Later that year, deer had eaten 95 percent of them. The next year the orchids gamely sent up another flush of flowers. And again the deer mowed them down.
In 1989, the fence went up. But the orchids had been deeply wounded. Three straight years of intense cropping had sapped their underground reserves. Convalescing inside their cage, the lady’s slippers took a decade to fully recover. “Without that cage, I don’t think they’d be here,” said Gregg. “The deer just mowed them, eating them to the ground. If it had gone on much longer, the population would have been gone.”
With deer now the reigning predator of the woods, life for the showy lady’s slipper has become a perilous existence. Gregg reveals that not all uncaged lady’s slippers are getting chewed by deer. In fact a free-growing population remains farther south, in Tennessee. The botanist who studies them does so by rappelling down the walls of the cliff on which they grow.
Must We Shoot Deer?
In 1992, the biologist Jared Diamond penned a famous essay entitled “Must We Shoot Deer to Save Nature?” Diamond had spent a “magically beautiful, but painfully upsetting, day in Fontenelle Forest near Omaha.” A thirteen-hundred-acre tract of Missouri River floodplain forest, Fontenelle is one of the few surviving forests along banks dominated by suburbs and farmlands. The intent to protect the forest from human harm—no hunting, no fishing, no flower-picking—had produced instead a macabre museum of the living dead. Diamond saw old oaks and hickories but no seedlings. Their under-story nurseries had become “a haven for ‘deer-proof’ plants, such as poisonous snakeroot and stinging nettles.” Birds and butterflies were disappearing. “The sight felt like visiting an apparently thriving country and suddenly realizing that it was inhabited mainly by old people, and that most of the infants and children had died,” Diamond wrote.
Our fault, confessed Diamond. “We provide the equivalent of supermarket conditions for deer by breaking the landscape into the habitat mosaics that they prefer, planting crops on which they feed, and eliminating the big carnivores that used to keep down their numbers.” Without those key predators patrolling the food web, he said, “what we’re trying to preserve is no longer the pristine self-sustaining ecosystem that nature could manage unassisted, but an already collapsing ecosystem incapable of sustaining itself.”
“It’s easy for me,” Diamond excused himself in closing. “I’m not the one who will have to explain to the public why they can’t pick flowers in a reserve where deer are shot.”
Diamond was wise to count his blessings. Within the decade the shooting had indeed started, in both directions. With some of the last bastions of biological diversity under plague of the hoofed locusts, conservationists started killing. The Audubon Society, better known for hunting birds with binoculars, went on record in favor of gunning overstocked deer; the Nature Conservancy, manager of the largest private system of nature reserves in the world, started opening some of its most heavily besieged sanctuaries to crews of archers and riflemen. Antihunters and animal rights activists fired back with protests, media campaigns, and op-ed grenades suggesting the hunts were merely cruel excuses to kill.
But some of the most vehement opposition came from hunters themselves, for whom there could never be too many deer. And nobody felt their wrath like Gary Alt. In the year 2000, after a long wildlife career spent crawling headfirst into bear dens, the biologist Alt enlisted for a new post on the Pennsylvania Game Commission to save the forest from its deer. The forests of Pennsylvania, browsed by the largest deer herd in the East—to the chagrin of foresters and conservation biologists, and to the delight of Pennsylvania deer hunters—had entered a state of reproductive arrest. (Among the few trees still regenerating was black cherry, a tree with cyanide in its tissues.) Alt’s first task was to deliver the bad news to the public, among them a powerful culture of hunters beholden to their behemoth herds. Alt soon came to long again for the safety of a bear den.
Night after night, in a 225-town tour of Pennsylvania, Alt played to overflowing auditoriums, projecting on big screens the damning photos of fence lines, delivering the same dark sermon. “If you care about forest ecosystems, if you care about wildlife, if you care about hunting or just care about deer, this ought to drive you to your knees,” Alt would say, pointing to the deer-beaten side of the fence. “You can’t grow deer in this habitat on the left. For seventy years we have had more deer in that system than we should have. Healthy deer can double their numbers in two years. Devastated habitat may take decades to recover.”
The obvious remedy to Alt and his fellow biologists was heresy to the Pennsylvania deer hunter. For suggesting more deer needed to be shot, Alt was sworn at, spat on, and threatened with death. He began reporting for work in a bulletproof vest. His crusade eventually cost him his marriage and his job. After twenty-eight years with the Pennsylvania game department, Alt resigned, moved to California, and took up photography and leading natural history tours. A happier Alt later sa
id, “I would rather walk into a grizzly den unarmed than try to sell deer management in the state of Pennsylvania.”
Coming Soon to a Neighborhood Near You
Huntley Meadows Park is an ancient meander of the Potomac River south of the District of Columbia, encompassing two square miles of oak woods and wetland meadows, with a population of white-tailed deer that not long ago numbered 250 (roughly twenty times the park’s ecological carrying capacity). When Gary Roisum came on as park manager in 1978, there was already a browse line forming in the understory, and the ground cover was growing noticeably sparse. In the mid-1980s, Roisum noticed a patch of exotic grass growing near the visitor center. Microstegium vimineum, Japanese stilt grass, is an immigrant from Asia first spotted in Tennessee in 1919, supposedly arriving in a crate of porcelain, which it was used to pack. Roisum would come to wish he’d yanked that harmless little patch when he had the power to do so.
By the 1960s, Japanese stilt grass had appeared in all the Atlantic states from New Jersey south. As the conservation community caught wind of it, Microstegium emerged as no run-of-the-mill garden weed. A single plant could produce a thousand seeds; it could survive ten weeks underwater and grow to maturity in the weakest light of the forest. Microstegium, it turned out, could alter the soil chemistry to the demise of its competitors. And whatever Microstegium couldn’t overcome on its own, with whitetails they could. With their hooves the whitetails prepped the stilt grass’s soil, with their incisors they cleared the competition. Roisum watched as each season the green wave of stilt grass rolled farther across his sanctuary, spreading in a front like a slow-moving fire. He pleaded for defense funds that never came. Together, deer and stilt grass blazed through Huntley Meadows, immolating the spring beauties and violets and pink lady’s slippers along the way. The deer browsed the high-bush blueberry to stubs. No seedlings of hickory, ash, oak, or sassafras reached beyond the molar zone of a white-tailed deer. Roisum’s park was under attack.
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