The Rewilding: The Trophic Tango
1. Standing in the Dark Looking In
In a dream I am an ecologist who studies wolves and elk. I am doing field research that involves looking intently into the uncurtained, brightly-lit windows of a two-storey Colonial house to observe the animals who dwell within. My objective is to measure their behavior (how they use space and resources) and discern patterns and relationships. Partly hidden by a shrub, I stand outside the house. I have my clipboard, data sheets, and mechanical pencil in hand, and a neatly formulated hypothesis in mind.
Only the animals aren’t cooperating. They’re behaving in ways beyond the pale. As I stand there, a watcher in the shadows, a strong wave of cognitive dissonance hits me. Like vertigo, like looking in a funhouse mirror and seeing the floor where the ceiling ought to be.
Inside the house my study units, as we call them in ecology, are in the dining room at a round table set with a damask tablecloth, fine china, and sterling silver. Two elk sit companionably with two wolves, their body language relaxed. Tapers burn brightly in twin silver candlesticks. With impeccable manners, the elk dine on what looks like kale sautéed with chanterelles. The wolves eat prime pieces of very rare meat. They carefully cut into their steaks with bone-handled steak knives. The knives’ razor-sharp blades glint in the candlelight. The quartet converses convivially. They sip a blood-red wine. At one point they raise their glasses and clink them together. When they finish eating, they move into the living room and put on music, loud enough that I can hear that it is a tango. They then dance with passion and wild abandon, first in single-species couples and then in wolf-elk pairs.
I stand outside, a scientific voyeur, astonished. I try to record these unprecedented intraspecies behavioral interactions—wolves and elk socializing. Lacking the proper categories on my data sheets in which to enter these observations, I scribble notes madly, my heart pounding. I press too hard, snapping the lead in my mechanical pencil. Could it be? Wolves eat elk. Elk fear wolves, because wolves eat them. Yet the animals in the house aren’t behaving according to the ecological paradigm. My hypothesis—that elk will avoid wolves—doesn’t fit. I realize that the only way for me to understand what’s happening is to go inside. Clutching my clipboard, I walk to the house and knock on the front door. My dream ends there, leaving me in the dark with many unanswered questions.
2. Out of the Garden and Back
In my waking life I live that dream. I conduct research on food web relationships called trophic cascades. The term trophic simply means food, and a cascade is like a waterfall. Specifically, I study the wolf, an apex predator, and its relationship with its primary prey—which happens to be elk in my northern Rocky Mountain study area. The ecology of fear, as it’s called, works like this: Fear of being eaten by a wolf forces elk to nibble plants warily and look up frequently, rather than standing around complacently browsing aspens and shrubs to death. This trophic tango indirectly influences many other species, such as birds that depend on plants for nesting and feeding habitat. In this manner, the wolf’s tooth touches everything in an ecosystem. However, like the tango, these top-down dynamics are far from simple.
Philosophically, my research represents a pronounced departure from how until very recently humans saw nature and the act of predation. Over 2,000 years ago, the Bible used stories to reinvent our human relationship with nature from being just plain denizens of it to being its rulers. The fall from the garden is one of the best known of these stories. When Eve takes a bite from the forbidden fruit, God expels her and her mate Adam from an Edenic paradise into a savage, dangerous world. To survive, they live by their wits and by the Biblical doctrine of dominion—man over nature.
Science arose at the same time as the Bible, born out of the work of philosophers such as Aristotle. His many claims to fame include Historia Animalium, his attempt to categorize nature. But his use of logic to explain natural phenomena represents his most revolutionary contribution to science.
The modern scientific movement began in 1637, when mathematician and philosopher Rene Descartes wrote “cogito ergo sum,” which means, “I think therefore I am.” With these words he created the existential I, and defined it dialectically by all that is not I. Humans, therefore, were outside of nature. Descartes then established a scientific framework that enabled us to study nature systematically and empirically. In doing so he created the practice of asking scientific questions in the form of hypotheses, which could be either true or false. This dichotomous logic did much to help us make sense of the world, but it widened the chasm between us and nature caused by the fall from the garden.
Two hundred years later, the hermit Henry David Thoreau attempted to bridge this chasm. To understand why wildness mattered, this peripatetic curmudgeon lived alone in a woodland cabin for two years. By day he obsessively roamed the woods; by night he wrote in his journal, reflecting on his experiences. In 1946, when he wrote, “In wildness is the preservation of the World,” he sparked the modern conservation movement. In the decades that followed his iconoclastic environmental ethos began to take hold, but the doctrine of dominion continued to rule.
By the 1920s humans had misguidedly wiped out most of the wolves in North America, thinking that the only good wolf was a dead one. Without wolves preying on them, elk and deer (called ungulates) exploded in number, creating more food for humans. Burgeoning ungulate populations ravaged plant communities. Yet, even as humans were pulling the trigger on the last wolf in Yellowstone National Park, the Thoreauvian movement had opened a new realm of possibility.
Thoreau’s powerful words seeded today’s environmental zeitgeist, which includes laws such as the Endangered Species Act and the field of conservation biology—defined literally as the science of saving nature. In the 1990s, conservation biologist Michael Soule coined the term rewilding to refer to restoring wildness to the planet. Since then, rewilding has evolved into the study of the ecological value of wildness and a paired social movement to return to a more primitive, primal, and connected way of life. In his Rewilding Manifesto, environmental journalist George Monbiot advocates abandoning the doctrine of dominion, restoring the garden, letting the wild things roam, and then sitting back and letting nature take her course.
3. Mending the Web
In the 1990s, 70 years after we’d hunted them, set them on fire, poisoned them, turned them loose with their jaws wired shut so they’d starve to death, and trapped them into extinction, we let wolves return. This rewilding took two forms. Some wolves, such as those that returned to northwestern Montana, where I lived at the time, simply came down from Canada on their own, drifting like smoke into remote, narrow mountain valleys. However, in 1994 we played God in Yellowstone, in a now legendary attempt to right a wrong by reintroducing wolves there. Besides ethical considerations, the rationale for this rewilding had to do with science.
Scientific evidence of the importance of top predators arrived in the 1960s and ‘70s with Robert Paine’s sea star and James Estes’ sea otter studies. In two different habitats (the rocky intertidal zone and the ocean), both scientists showed that ecosystems without apex predators begin to unravel. Prey take over, eating plants such as kelp unsustainably. As biodiversity plummets, these debilitated ecosystems enter an extinction spiral. Paine created the metaphorical term keystone species to refer to apex predators and noted that when you remove the keystone, arches and ecosystems collapse.
And so like a mutual act of faith (or what those who don’t like wolves consider a joint act of defiance), we let wolves return—and they obliged. They set up housekeeping, often denning where they’d denned a century earlier, and using the same hunting grounds. Like a flesh-and-blood primal manifesto, upon their return wolves rapidly sent their ecological force rippling throughout the land, restoring the American West from the top of the food web to the bottom. The ensuing recovery of plants that elk had been eating to death in the absence of wolves has become one the most popularized and beloved ecological tales. Yet today scientists caution that this story is more myth than fact because nature isn’t so simple.
In the years since Paine’s and Estes’ seminal studies, ecologists have found trophic cascades—also called top-down effects—ubiquitous from coral reefs to prairies to polar regions. However, scientists also have found that sunlight and moisture, which make plants grow, drive ecosystem processes from the bottom-up, making predators relatively unimportant. For nearly four decades, the top-down vs. bottom-up debate has been one of the most acrimonious in ecology. The northern Rockies wolf recolonization, which happened literally in my backyard, provided the perfect testing ground for these contrasting views.
The top-down perspective holds much valence with me. I used to have a large meadow on my Montana land in which white-tailed deer and elk would stand around peacefully eating aspens and shrubs down to nothing. When wolves returned in the late 1990s, these ungulates had to stay wary and on the move to avoid begin eaten. And within five years, un-browsed aspens and shrubs had filled my meadow, providing a home for long-absent songbirds, such as the American redstart. I became so curious about these relationships that I went to graduate school and studied them. I wanted to use science to show how the wildness carnivores bring to a system touches everything and can create healthier ecosystems.
In the mid-1800s in his book The Origin of Species, Charles Darwin presciently described nature as a “tangled bank.” Nature’s complexity results from myriad species and their relationships with other species and all the things that can possibly affect them, such as disease, disturbance, and competition for food. Science works incrementally, taking us ever deeper into that tangled bank as we investigate ecological questions. Each study answers some questions and begets new ones. Sometimes we find contradictory results. Learning how nature works requires that we keep searching for answers amid the clues nature gives us, such as the bitten-off stem of an aspen next to a stream where there are no wolves.
In my own research I’ve found that wolves alone don’t always produce strong top-down effects. They sometimes need another keystone force—fire—to create trophic cascades. In my previous work in Glacier National Park, Montana and in ongoing Earthwatch research in Waterton Lakes National Park, Alberta, we’re experimenting with fire in a wolf-dominated system. Our first five years of data show that with wolves and fire present, elk herbivory drops, aspens thrive, and biodiversity soars due to the healthy habitat created by young, vigorous saplings. However, parsing this complex weave of top-down and bottom-up relationships has been complicated. And even after gathering data on 35 ecological variables and building dozens of statistical models, I missed a key point. What I failed to realize was that the “everything” that wolves touch in a food web includes us.
4. Gifts from the Garden
When you do field research, you end up drawn into the tangled bank you study. No amount of empirical thinking, hypothesis testing, or attempts to remain objective and unbiased can change that. Therein lies the primal paradox: that as much as we see ourselves as nature’s stewards and observers, we’re also part of nature. This connection runs so deeply that it’s embedded in every fiber of our being, in every breath we take, and every strand of our DNA.
Thoreau inadvertently sharpened this paradox. Conservationists that came later, such as John Muir, interpreted his words as a call to set aside protected wilderness lands untrammeled by humans. And so we created the 1964 Wilderness Act and over 109 million acres of federal wilderness areas. At first glance, the concept of hallowed ground free from human extractive activities such as logging and mining represents a move back to the garden. But looking closer it becomes obvious that this concept is flawed, because by accepting that nature must be rewilded, then as modern humans our very presence in nature signifies its downfall.
The trouble with wilderness, according to environmental philosopher William Cronon, is that it implies that where we are is where nature is not. Wild or rewilded nature is a place we visit or pass through. However, if we accept that in order to save nature, our presence in nature represents its loss, we’re buying into the false dichotomy that led to nature’s degradation by humans in the first place. We also are accepting all the false dichotomies created by scientists, such as that nature is a place where elk and wolves behave in a predictable manner. Tangled banks don’t support such notions.
Like all scientists, I was trained to separate myself from what I studied. To produce best science, I became that scientific voyeur, impartially recording data. Fortunately, in my case, my study units reached out to me and very primally let me know that nature didn’t quite work that way.
A few summers ago I was working in a meadow in Glacier National Park, Montana, measuring trophic cascades in an area that had a high wolf density. Well-acquainted with these wolves, I had put collars on two of them and over the years had spent hundreds of days immersed in the landscape in which they lived, measuring their tracks and sign, their trail of carcasses, and how their presence indirectly affected everything in this ecosystem.
It was just before dusk. We’d been hearing the wolves howling that day, their voices rising and falling, weaving together, coming from all around us. This paean to wildness felt oddly comforting. Wolves use howling for a variety of purposes, including communication with members of other species. We’d also been finding grizzly sign in the willows that grew among the aspens—dinner plate-sized fresh scats filled with roots and shoots. Many bears and other carnivores roam the area where I do my research, indeed some say it contains one of the highest densities of large carnivores in America. To maintain peaceful relations with these creatures I avoid their foraging grounds during crepuscular periods—dusk and dawn.
We had one more plot to measure to complete our survey, but it was late, and I sensed it would be best to leave. We marked it, six feet in radius and on the edge of the aspens, with pink pin-flags arranged in the cardinal directions and left. As we filed out of the meadow on a well-worn game trail, the wolf howls continued. Piles of elk scat marked the trail, along with abundant wolf, cougar, and bear scat, providing bold evidence that this was a heavily-used carnivore trail as well.
The following morning we returned to finish our survey. As we approached my plot, there, in its center lay a carcass—or to be more precise, one quarter of a freshly-killed elk. A scatter of bloody wolf tracks lay around the hunk of elk like scarlet blossoms on grass. We looked at the meat incredulously. It had not been there the previous day, but here it was—most of the hindquarters of an elk, the backstrap still attached, all neatly contained within my plot. As we pondered the meaning of all this, we heard a guttural huff from just inside the aspen stand. There, backlit by the morning sun, stood a grizzly bear, rearing up on its hind legs, announcing its keen mutual interest in the elk meat. I had prepared my crew for such situations, when showing fear would only provoke an attack. We left, walking calmly and straight-backed out on the carnivore trail that had taken us into the meadow.
One week later we returned to finish the plot, but met the same bear, who was napping just inside the aspens this time, and who huffed at us again. The elk carcass had been reduced to little more than sinew and bone by then, but the bear was still possessively positioned, perhaps hoping for another gift from the wolves. We left again. It wasn’t until two weeks later that we finally were able to finish surveying my plot. In it I found many young aspens, growing straight and true and only lightly browsed, providing abundant evidence of a trophic cascade.
Whether mindful gift or accident of fate, that hunk of elk meat in my plot taught me much about our connections to the wild. If we honor the howl of wolfen voices, the sleeping bear, the primacy of a freshly killed elk and the gift its meat provides to whole ecosystems, we’ll be that much closer to learning to live sustainably on this earth. And it made me reflect on who we really are beneath the layers civilization has imposed on us.
5. Letting the Wild Rumpus Begin
Today we’re learning that there’s no real separation between humans and the wild. Poor science makes them separate. The lessons the animals I study bring to me in my dreams and field plots have taught me that we’re all in this together. The irony is that the primal paradox is irresolvable. Rewilding means acknowledging this ultimately irresolvable paradox and moving on. Doing good science also calls for acknowledging that the more we try to keep ourselves separate from the systems we study in order to produce unbiased science, the more we’re part of them. Moreover, the truth is ultimately unknowable. No matter how many hypotheses we test, all we can do is get closer to understanding how nature’s tangled bank works.
Like the doctrine of dominion, traditional scientific method has failed us because we continue to apply two-dimensional logic to a multi-dimensional, fractal world. Scientists are responding to this primal paradox by learning new ways of thinking about nature. For example, we’re developing nonparametric statistical tests that acknowledge and embrace nature’s fractal, non-linear characteristics. The answers some are finding are helping us understand that animals inhabit that tangled bank at multiple scales and what we can do to save them in a world in crisis.
The wounds we’re attempting to heal—climate change, habitat fragmentation, and the resulting rampant species extinctions—defy simple solutions. The only way to heal them is to return to an ancient way of relating to nature in which we see ourselves as an intrinsic part of the fractal whole—like one of a set of nested Russian matryoshka dolls. This means boldly exploring new philosophical horizons that can help us take needed scientific leaps. And based on my dreams, for me personally it means learning to dance the trophic tango in which top-down and bottom-up effects conjoin and move to the heartbeat of life.
A week or so after my elk and wolf dream, I had another that served as an epilog. In this dream I am inside the colonial house that was in my first dream. I am in the dining room sitting at the table with elk and wolves—a pair of elk on my right, a pair of wolves on my left. The elk closest to me fills my wineglass. The wolf on my left raises her glass and initiates a toast: l’chaim—to the rewilding. The five of us clink glasses. I sip from the rewilding cup. The rich, complex wine tastes of fir trees, sweet huckleberries, smoky earth, and ineffable wildness. We drink deeply, and then the wild rumpus begins.
Cristina Eisenberg, Black Earth Institute Scholar Advisor, is the Lead Scientist at Earthwatch Institute, where she develops and helps support a global research program as an ecologist she studies wolves and fire in Rocky Mountain ecosystems. She has a master’s degree in conservation biology from Prescott College and a PhD in Forestry and Wildlife from Oregon State University. She is a Smithsonian Research Associate, a Boone and Crockett Club professional member, and the nonfiction editor of the literary journal Whitefish Review. She serves on the editorial board of Oregon State University Press. Her books for Island Press include The Carnivore Way: Coexisting with and Conserving America’s Predators, and The Wolf’s Tooth: Keystone Predators, Trophic Cascades, and Biodiversity. Her nonfiction and poetry have been published in a variety of literary journals. She currently lives in Massachusetts, in a farmhouse near Walden Pond. She blogs regularly at http://www.huffingtonpost.com/cristina-eisenberg/.