91成人短视频

A Geography of Hope

The 2004 LaFollette Lecture

October 1, 2004

I begin with a vignette. On a lovely spring morning last year I stood waist-deep in the Madison River in Yellowstone National Park, releasing a 20 inch rainbow trout. Before beginning to cast again, I glanced at my surroundings. On the far shore a cow elk and her twin calves grazed the lush grass sprouting beneath the pines charred by the 1988 fires. The cow did more watching than eating but the calves, unconcerned, grazed and moved in synchrony the way cervid twins always do. Just downstream from me a bald eagle was perched on a snag above the river. Like me, he was watching the river for rising trout. On the near shore a coyote glided down an elk trail stopping occasionally to sniff at ground squirrel burrows. It was a marvelous moment, an iconic and idyllic scene: Yellowstone at its best; the world’s first national park; America’s best idea. A watercolor of the moment could be sold in the gift shop.

I have lived a charmed life for I have a thousand such mental images—moments captured and stored as internal landscape photographs. There is an image of a musk ox, that quintessentially Pleistocene animal, shambling out of the Noatak River in the Brooks Range as our canoe glided by. Another as I stood in the last warm light of sunset before a single prairie fringed I’d driven five hundred miles to see. Still another is a bitter cold and sleepless night alone on the summit of Mt Whitney while thunderstorms flashed below me in the valleys to the east and west. There is a slather of mallards, wings locked, turning in unison to glide into a prairie pothole in North Dakota. In yet another, a whale erupts from a dead-calm sea, not fifty feet from our kayak. These images sustain me. They bring me peace. They inspire my work. I can call them up at the times I need them most.

I believe we live in a culture that especially values the natural world. Roderick Nash, historian of the environmental movement, points out that early in our history we suffered from a national inferiority complex. Americans saw themselves as bumpkins, hopelessly uncultured relative to Europeans. American intellectuals envied the long artistic, musical, and literary history of Europe. Eventually, we found pride in the fact that we had in abundance one thing Europe had not known for a thousand years: wilderness. Wild nature became the subject of our earliest literature and art. Moreover, as we worked our way across a wilderness continent, the wilderness worked on us as well. Wild country gradually insinuated itself into our psyche and our culture. We became a people shaped and defined by nature.

All of us value in some way those personal moments of connection to nature. They are mementos of our bond with the natural world, universally valued. I realize my own interaction, by vocation and avocation, is at the far end of the bell curve. And I am perhaps more self-conscious about it as well. Nevertheless, we all share in some way the need for those moments—whether a gentle walk through Pine Hills or an extended immersion in the wilderness. And there are those among us whose contact with nature is solely vicarious, who simply cherish the idea of a natural world somewhere out there.

But let me return to that moment on the Madison, my natural moment, and think out loud about it as a professional ecologist. From this point of view, everything I described was wrong; nothing was natural. Twinning in elk is uncommon. It is a response to an enhanced food supply. The grass on which they grazed was unnaturally lush—the response to a fire begun outside the park as an untended campfire. Invasive non-native grasses, escaped from overgrazed country outside the park, are replacing the native species.

The bald eagle is supposedly a success story. On the brink of extinction in the 1960s, eagles recovered thanks to the protection of the Endangered Species Act and the removal of DDT from the environment1. It’s a nice but incomplete story. Because eagle populations were so drastically reduced—a bottleneck to biologists—this individual and its species carry a tiny fraction of the genetic variation they should. We have deprived them of the wherewithal to adapt to an environment that will inevitably change.

The coyote is problematic as well. I see coyotes every day in Yellowstone because their populations are abnormally high for two anthropogenic reasons. Coyotes and wolves do not mix well and wolves generally displace coyotes. Early in the 20th century the Park Service, in an attempt to increase game populations popular with visitors, targeted virtually all predators for removal. When wolves were extirpated coyotes increased dramatically. Why didn’t trapping depress coyote numbers? The answer lies in the peculiarities of coyote behavioral ecology and the mathematics of their population dynamics. Unless you are able to remove 70% of the adult population of coyotes, you will end up with more than you started with.

Alas, that fat rainbow trout was artificial as well. Rainbows were introduced from the Pacific Northwest and are gradually out competing and hybridizing with the native cutthroats to the point that the latter may soon be placed on the endangered list.

What of my iconic image now? Is it an image of a momentary intrusion into a lovely, healthy wilderness? Or is it an image of a world in decay? Perhaps I’ve lived too long. There are times I mourn for the world I knew before I knew so much. As Aldo Leopold tells us, “One of the penalties of an ecological education is that one lives alone in a world of wounds”.2 This story leads me, finally, to the question that will guide this talk. It is a question my students often ask. My advanced ecology students inevitably raise it after a week in the Okefenokee, Florida Keys, and Everglades. As we sit by the shore at Flamingo on a warm, starry night after a week of marvelous biology tempered by the overwhelming unnaturalness of South Florida, I can count on someone to finally ask, “How can you possibly remain positive when you know what you know?”

At first glance this is perhaps a trivial question for a serious talk. It begs to be answered in glass half-full/half-empty banalities. But in fact, it is a significant question in the post-modern world. And to answer it we need to address two other questions: What do we value about our interaction with the natural world? And, how should we manage and conserve wild places to provide those values? The first question, the matter of value, is the province of the humanist. The latter is a scientific question. Together they invite a conversation about the relationship of my science to the humanities, my charge for this talk.

Bob Petty presented what was, I believe, one of the best of the Lafollette Lectures, entitled The Margins of Knowledge. In it, Bob said,

I do believe that all of us can and do learn much at the far margins of our own disciplines, at the frayed borders between our own understanding and the unique knowledge of others. And that, even in attempting to do this, somehow we revalue our own discipline for its inherent worth as well as its rightful limitations….. Only at the margins of knowledge can we discover some essential, critical perspective of the field we labor in, and come to a better definition of what lies at the center—perhaps even what matters most. 3

A coalition of scientists, writers, and artists has labored long and hard to protect the earth. This endeavor requires each group to work at the margins. Their contributions lie at the intersection of ecology and human values and experience. The humanists who write and speak for the earth articulate the value of a healthy planet and inspire our commitment to protect it. Neither value nor inspiration is properly the province of science but in the case of protecting the earth, both are connected to scientific principles. Wendell Berry describes science and the humanities as two distinct kinds of implements that together are part of the human tool kit. Although he is skeptical of a true unification of the two cultures, he allows that the only reason for the combined tool kit is to “build and maintain our dwelling on earth”. 4

If I am to address the relationship of my discipline to the humanities, I will need to talk about science. For a scientist, the Lafollette, by definition, demands Petty’s approach—to work near the margins. Although I will generally stay safely on the science side of the boundary, I will at least peer across it and reflect on what I can see of the other side. But in the end I will return to my home territory. This is due partly to my own ignorance and the fact that my charge is to reflect on my discipline in relation to the humanities. But it is also because I want to argue that science has something important to say to the humanities. In the end it is my science, not the earth poets, that sustains my hope and confirms my optimism. Despite the fact that my science systematically shattered for me, and now for you, the beauty of that moment on the Madison, ultimately it is my science that lets me live with hope in wounded world.

What do we value about the natural world? Here I’m not interested in what environmental scientists call “ecosystem services”: cleansing our water and air, pollinating our crops, or moderating the climate. Neither am I interested in preservation simply to ensure a good stock of potential cures for cancer. That moment on the Madison had not one practical consequence for me and that was precisely its value. In his wonderful 1994 Lafollette, Marc Hudson argued that scientific reasons for stewardship are

too cold, too abstract. They are good reasons, pragmatic enough for any accountant, and I am grateful to science for them. But that we must trot them out suggests a lack of caritas for creation, that ‘tenderness toward existence’ 5

It is the writer, the artist, and the earth poet who express for us the value we derive when our lives intersect the natural world.

What do we learn from them? It’s absurd to summarize a literature so vast so briefly, but here it goes. I believe they help us understand that we seek aesthetic and spiritual rebirth triggered by something beyond human creation. We seek something outside ourselves, something bigger, something mysterious, something mystical, and for some, religious. As expressed by John Burroughs, “We do not see ourselves reflected there—we are swept away from ourselves, and impressed with our own insignificance”. 6

Perhaps no one articulated the value we derive from that “tenderness toward existence” better than Wallace Stegner. Stegner understood that the universal human need for wild places is particularly well developed in Americans.

Something will have gone out of us as a people if we ever let the remaining wilderness be destroyed; if we permit the last virgin forests to be turned into comic books and plastic cigarette cases; if we drive the few remaining members of the wild species into zoos or to extinction; if we pollute the last clear air and dirty the last clean streams and push our paved roads through the last of the silence, so that never again will Americans be free in their own country from the noise, the exhaust, the stink of human and automotive waste. And so that never again can we have the chance to see ourselves single, vertical and individual in the world, part of the environment of trees and rocks and soil, brother to the other animals, part of the natural world and competent to belong in it…..

We simply need that wild country available to us, even if we never do more than drive to its edge and look in. For it can be a means of reassuring ourselves of our sanity as creatures, a part of the geography of hope.7

Ultimately, it is hope we seek.

What kind of place generates the moments we cherish? Our assumption has been that we find these moments in complete, functioning ecosystems—places of “organic wholeness”. There is in fact, a scientific term for such a state: the balance of nature. I want to expend some words on this phrase because it is central to what I want to assert today.

The roots of the concept are deep. George Perkins Marsh was a visionary, revered by environmentalists for conceiving amidst the abundance of the 19th century, the idea that American resources are finite. Marsh also was among the first to articulate the concept of the balance of nature. In his words, “Apart from the hostile influence of man, the organic and inorganic world are…bound together by… mutual relations and adaptations”. 8 Marsh goes on to describe an equilibrium condition that persists until upset by humans. The early ecologist A.G. Tansley first used the term ecosystem, to describe a beautifully balanced “superorganism”. The superorganism develops in a fashion analogous to the growth and development of an individual. When development is complete, the system “represents the highest stage of integration and the nearest approach to perfect dynamic equilibrium that can be attained…” 9 The plant ecologist Frederick Clements also conceived of plant communities as superorganisms, each species of which is essential to the balanced functioning of the “being”.

The idea was prominent in some of the earliest writing in defense of the earth. In the1920s, decades before he wrote A Sand County Almanac, Aldo Leopold acknowledged a superorganismal nature.

Possibly, in our intuitive perceptions which may be truer than our science and less impeded by words than our philosophies, we realize the indivisibility of the earth—its soil, mountains, rivers, forests, climate, plants, and animals, and respect it collectively not only as a useful servant but as a living being, vastly less alive than ourselves in degree, but vastly greater than ourselves in time and space—a being that was old when the morning stars sang together, and, when the last of us has been gathered unto his fathers, will still be young. 10

The idea is also central to one of John Muir’s most famous statements: “As soon as we take one thing by itself, we find it hitched to everything in the universe”.11 As the science of ecology developed, so too did this paradigm, as a model of natural systems. Populations, communities, and ecosystems were understood to function as highly integrated and balanced entities. The giants of 20th century ecology, David Lack, Robart MacArthur, and Charles Elton, emphasized the key role of negative feedback systems that regulate everything from lemming population cycles to the flow of carbon on the planet. Central to the paradigm was the notion that long periods of stability are punctuated by rare disturbance events. In this view, the process of ecological succession quickly restores the static, balanced community. It was but a short step from these ideas to the generalization that nature operates in dynamic balance unless and until we disturb it.

By 1968, the paradigm had reached its ultimate extension in the form of Lovelocks’ Gaia Hypothesis. The idea of the “balance of nature” was extended far beyond its original concept to include the entire planet. Lovelock defined Gaia as the totality of the planet, a superorganismal entity that seeks optimal conditions to maintain life. Active control by feedback systems maintains balance—and life. 12

The paradigm also shaped our fundamental approach environmentalism—how we should care for the natural world. The traditional argument asserts that humans perturb the balance, hence the importance of limiting nature’s exposure to us. We may visit natural systems briefly but the longer we are there and the greater our numbers, the more likely we are to upset the balance nature tends toward in our absence. This is part of the appeal of my initial iconic image of Yellowstone. My presence there was fleeting, non-extractive, and benign.

The environmental coalition seized upon the concept of balance as the natural ideal, as the goal of the movement. Nature “in balance” became the holy grail. Essayists and poets exalted balance and condemned our capacity to destroy it. Those who wrote with a specific preservationist agenda such as Marjory Stoneman Douglas for the Everglades or Mardie Murie for the Arctic National Wildllife Refuge, based their arguments at least in part on the need to preserve a natural balance.13 For others, the balance of nature provided the scientific control by which we measure our negative effect. Stegner argued that one value of wild country is as a “scientific yardstick by which we may measure the world in its natural balance against the world in its man-made imbalance”.14

How convenient that science provided such an unambiguous ideal. The paradigm is simplicity itself: the natural world is in lovely balance unless and until altered by humans. Moreover, the scientific, spiritual, and aesthetic ideals are coincident. They can be articulated equally well by the field biologist, the poet, and the artist. A poetic description from Robinson Jeffers:

Integrity is wholeness,

the greatest beauty is

Organic wholeness, the wholeness of life and things,

the divine beauty of the universe.

Love that, not man apart from that…15

The scientific view, from Leopold, is not fundamentally different:

The outstanding scientific discovery of the twentieth century is…the complexity of the land organism. If the land mechanism as a whole is good, then every part is good, whether we understand it or not. 16

For once science and the humanities were not at odds. I won’t spend the words to enumerate the ways that scientists have historically antagonized the humanists and vice versa. Suffice it to say that both cultures delighted in a shared vision of the world and a common goal. There was even room for God—the balance of nature was perfectly compatible with the perfection of creation. The coalition of earth poets, essayists, and artists, secure in the scientific validity of the balance of nature paradigm, was poised to defend the earth.

The paradigm framed the conversation about strategy as well. Two schools emerged: the preservationists who argue that humans affect the balance and must be shut out and the conservationists who believe that as stewards and managers, humans can effect balance. As we worked through the environmental disasters of the early 20th century, the preservationists gradually dominated the mainstream environmental movement.

The preservationist view certainly dominated the humanist’s contributions. For example, Robinson Jeffers created earth poems that in his words:

present a certain philosophical attitude, which might be called Inhumanism, a shifting of emphasis and significance from man to non-man; the rejection of human solipsism and recognition of the trans-human magnificence. It seems time that our race began to think as an adult does, rather than like an egocentric baby or insane person. 17

We see the preservationist ideal in the visual arts as well. Early in the 19th century the idea was already evident in the Hudson River school. Painters like Cole, Bierstadt, Church, and Durand evoked the dimension and grandeur of a world in balance. In the process they made clear statements about the role of humans. In these enormous canvases, nature is huge and magnificent; humans are vanishingly small and insignificant. But the human impact on the landscape, often depicted in a neat, well-ordered foreground economy, also foreshadowed the future and the end of nature. A few of these artists anticipated a different, and perhaps not better, future. Thomas Cole, in an 1836 essay on American scenery, warns that “the beauty of such landscapes [is] quickly passing away—the ravages of the axe are daily increasing—the most noble scenes are made desolate, and oftentimes with a wantonness and barbarism scarcely credible in a civilized nation”.18 The slide from pride and optimism toward despair began very early.

If we fast-forward to the twentieth century, the environmental photographs of Eliot Porter, Robert Glenn Ketchum and Ansel Adams represent another stage in the artists’ contribution to the coalition’s agenda—the use of photography to inspire and to define the environmental ideal. Ansel Adams’ photographs, for example, are an almost absurdly perfect metaphor for the balance paradigm and the preservationist agenda. They represent the inhuman archetype: no traces of humans or their works are visible. The photographs, like nature itself, are in balance in every dimension of composition and tonal range. Then “nature”, that is the image, is “fixed” by the last chemical bath and preserved on an acid-free mat under UV-protective glass. No wonder 20 Adams’ photos grace the walls of the Wilderness Society offices in Washington. They symbolize the program: Identify and define wilderness, keep humans out, and all will be well.

We now live on a planet with six billion humans. This century will see more than 10 billion people and a new level of human domination of nature. How can we possibly expect to achieve more than tiny, ecologically irrelevant islands of nature in balance? In such a world, art and literature that celebrate nature in balance document not the future we seek, but a past we must mourn. Look again at Ansel Adams’ Clearing Winter Storm (Yosemite), one of the most compelling images he ever made. I’ve watched patrons in a gallery turn a corner to confront a four by six foot print—and burst into tears. Compare that image with the depressing ecological reality of Yosemite Valley today. Adams’ intent in 1944 was inspiration; today his image is reduced to elegy. The same is true for the environmental literature. Read Sigurd Olson’s Farewell to Saganaga on the Quetico country. Or John McPhee’s Coming Into the Country on Alaska. Or Peter Mathieson’s African Silences. Or Edward Abbey’s Down the River, on Glen Canyon before the dam.19 Or Leopold as he contemplates the last grizzly taken from a desert peak:

Since the beginning, time had gnawed at the basaltic hulk of Escudilla, wasting, waiting, and building. Time built three things on the old mountain, a venerable aspect, a community of minor animals and plants, and a grizzly. The government trapper who took the grizzly knew he had made Escudilla safe for cows …. Escudilla still hangs on the horizon, but when you see it you no longer think of bear. It’s only a mountain now. 20

This is not art and literature that leads me gently into the “geography of hope”. It may be the source of my activism, but not my optimism. In an unbalanced world increasingly dominated by humans, it has become a literature and art of loss.

But there is good news. One of the defining characteristics of science is that its conclusions, and thus its principles, are tentative. It is time to discard the balance of nature paradigm and in so doing find a source of hope. We discard it, not because we don’t like where it leads us, but because it is untenable. There is no balance of nature—not because humans destroyed it—but because it never existed. The concept was established long ago as false ideal. The paradigm of equilibrium ecology began to unravel decades ago but still permeates science and literature at Bob Petty’s margins where the coalition works in defense of nature.

Why did it unravel? Let me explain with some biology at the center, rather than at the margins. The answer is both logical and empirical. I’ll begin with the logical. One of the appeals of the ecological balance paradigm is that it seems to be part of the grand unity of biology. The balance of nature is the ecological analog of the physiological homeostasis we see in individual organisms. Homeostasis, sometimes described as the “wisdom of the body”, is the tendency of individuals to maintain relatively balanced internal conditions regardless of the external environment. The biochemistry of life operates properly within rather narrow limits. Organisms inhabit a tremendous range of physical conditions on earth—from seas colder than freezing to boiling springs in Yellowstone; from salt water to fresh; from xeric desert to dripping rainforest. Thus, all individuals face enormous selective pressure to maintain an internal “balance of the body” different from the vagaries of their environment. Those individuals unable to do so are dropped by the wayside during the course of evolution.

Biologists are fond of describing a “hierarchy of life” that ranges in ever more inclusive units—from cells to tissues and organs, to individuals, to populations, to communities, to ecosystems. Ecologists like Clements and Lovelock extended the idea of the individual’s homeostasis “up” to populations and communities. The argument goes like this: in disturbed ecosystems, wildly fluctuating conditions eventually lead to ecological collapse and extinction. Thus, natural selection favors mechanisms that dampen these wild fluctuations and unstable interactions. The balance of nature is an adaptive response that is “good” for the ecosystem. Balance is as important to the community as homeostasis is to the individual. The argument requires that communities and ecosystems are subject to natural selection—life and death—in the same way individuals are.

As appealing and intuitive as this idea is, it is simply wrong. It fails because something profoundly important happens as we move up past the level of the individual in the biological hierarchy. A key discontinuity occurs at the level of the individual: Evolution is manifest only in groups but selection operates only on individuals. The converse is not true: individuals don’t evolve and groups are not selected.21 Natural selection cannot construct a cooperative, homeostatic community of organisms. The balance of nature, central to the environmentalist paradigm, requires it but evolution does not allow it.

The idea also collapses for lack of supporting empirical evidence. The data now overwhelmingly reject this model. We now understand that disturbance is common, stasis is rare. I won’t even attempt to convince you with the totality of the evidence—suffice it to say that virtually no ecosystem on earth can be called stable.22

There is yet another problem. The frequency of significant disturbance is sufficiently high that few ecosystems on earth are old enough to have developed the complex interrelationships required for balance. Thanks to the Pleistocene glaciations, no ecosystem north of 40oN is older than 9000 years. How then can we talk about the delicate balance of nature in the Arctic National Wildlife Refuge? It is too young. The ecosystem I study, the tallgrass prairie, arose in the last 8000 years from floral components migrating into the Great Plains from three different directions. For prairie plants that can probably live 100 years or more, that’s not enough time for a balanced ecology to evolve.

Ecologists shifted away from the balance paradigm more than a quarter of a century ago but the change still is not fully incorporated into the environmental movement. Why not? I think there are at least two key reasons. The concept is both intellectually and emotionally satisfying. A world in balance satisfies an underlying need for order. In addition, its simplicity and intuitive appeal facilitated its communication to the lay public and its translation into policy.

I suppose I’ve led you, like I apparently lead my students, not to hope but to despair. Not only is the biological world in obvious decay all around us, but our stewardship goal, our vision of ecosystem health, is false. How do we proceed in such a world? Curt Meine, conservation essayist and Leopold biographer, urges us to adopt what he calls an “irrational optimism”. For John Nichols, environmentalist and author of the wonderful environmental story, The Milagro Beanfield War, optimism is a matter of defiant faith:

Unfortunately, feeling even halfway positive in this turbulent day and age is not so easy. It takes a lot of courage and a lot of work simply not to be pessimistic. So many banal evils discourage the growth of a creative vitality. Shadows of malignant scaffolds hold the planet in a very negative net. Yet it can be done. And everything commences by refusing to despair; optimism is my one irrevocable act of faith….My dream is never to let them make me a cynical old man.23

Neither of these answers appeals to me because I think there is a more coldly rational reason for optimism. Let me gradually work toward an answer to my student’s question.

The fundamental fact of life is death. And ecology is the science of death—its spatial and temporal patterns and their probability distributions. My science catalogs the ways organisms die. From this science we learn that we do not inhabit a balanced, gentle, cooperative, superorganismal world. Physical disturbance in one form or another—glacier, storm, flood, fire, volcano—imposes death from without (its just one damn thing after another). As if that weren’t enough, death and disturbance are imposed by other living things as well. Every single organism on earth lives at the expense, direct or indirect, of others. I challenge you to find a single exception to that assertion.24 We live in a natural world that is unbalanced, stochastic, hostile, and transient. The earth’s evolutionary history is written in the countless ways species adapt to this ecology. The stunning diversity of life arose directly from the diversity of these ecological challenges and the myriad adaptive solutions to them. There are nearly as many solutions as there are species, that is, somewhere between 30 and 100 million. Evolution favors above all a strategy of persistence, not in defiance of change, but in expectation of change. The probability distribution of environmental change is immutable. It is imposed on the species from without. The resulting adaptive strategy is not an attempt to beat those odds, it operates according to them.

Let me steer my rambling toward hope with another vignette. Not far from my house is a tiny, roadside prairie remnant. Although it occupies just a few hundred square meters, it contains a number of unusual wet prairie species—American burnette, larkspur, grass of Parnassus, and the rare and stately Queen of the Prairie. It lies along my regular biking or jogging route and so I pass by it two or three times a week. As I pass by