I never wanted to live in Cincinnati, Ohio. What self-respecting wilderness lover would dream of moving to an old Rust Belt city straddling polluted rivers? One might dream of Spokane or Bozeman, but not Cincinnati, a town famous for laundry soap, machine tools, and indigestible chili. Sometimes it amazes me that I still live there a decade after arriving: the city has always seemed a sort of environmental hell, the source of pollution and habitat destruction and the forces that drive them. And yet I would like to tell some of the good I found there.

The very phrase "urban nature" seems paradoxical. We commonly think of "nature" as something opposed to civilization, a green world of diverse life-forms and complex ecological relations set apart from the gray world of human artifice, edifice, labor, and domestication. Nature is antithetical to this "built environment," and wilderness—where "the earth and its community of life are untrammeled by man [sic], where man himself is a visitor who does not remain," to quote the Wilderness Act of 1964—wilderness is the most natural nature of all. The necessary qualifier "urban" confirms that remoteness from cities is the norm, the standard field mark, the distinctive feature of Nature as reality and idea. It takes a leap of imagination, or faith, to think of nature and cities in the same mental frame. And yet this difficulty, this resistance to the very idea, suggests both an avenue of critique and an opportunity for learning. I would like to support this thesis with a brief anatomy of the resistance, followed by an examination of one particular issue, that of alien species.

No doubt you've heard about the Indian and the white man who were walking along the street when the Indian suddenly exclaimed, "I hear a cricket." The white man was incredulous, "How can you hear a cricket with all this traffic?" The Indian smiled, took out a dime, and dropped it on the sidewalk. Six people turned around. As he picked up the coin, the Indian said, "It all depends on what you listen for." If we listen for money more than for crickets, it should come as no surprise that we know more about the Dow or the NASDAQ than we do about the sequence of migrating birds or blooming wild flowers in our neighborhoods.

But, to be fair, most people have little reason to pay close attention to local nature. Consider the matter of where food comes from. In Cincinnati, I begin the day with a cup of Colombian coffee, an apple grown in Washington state (with a slab of New York cheddar on the side), and a slice of bread made from Montana wheat and spread with Georgia peanut butter or Connecticut blueberry jam. Ecologically speaking, I have more to do with a Montana wheat field than with the lawns and woodlots of Cincinnati. Such is not the case, of course, with indigenous people who depend on the local landscape, either as hunter-gatherers or as agriculturists. Scholars like Richard Nelson and David Abram have shown how close ecological dependence fosters intimate, personal relations among resident organisms and a spiritual sense of relatedness that is deeply embedded in local culture. In contrast to such "personal ecology," our urban life rests on an "impersonal ecology" that has removed the greatest incentive our species has ever had to pay close attention to the green world.

But there are other, more psychological reasons why urban nature remains largely invisible to us. For one thing, we don't have convenient ethical or esthetic categories for interpreting city landscapes. Take the green world in back of my house, which begins as an unkempt lawn and culminates in a belt of woods about a hundred meters deep. It's hardly sublime: there are no soaring mountains or plunging chasms. Nor is it picturesque: it's too thickly grown, too narrow in scope, with no glimmering lake or pond in the middle ground, no grazing cattle (or deer or buffalo), no decorative herdsmen or natives. You could not call it a garden, for no one tends it, the plants and animals grow wild, there's no plan or esthetic in their arrangement, no intentional statement of any kind; it's far from both art and husbandry. Nor does it qualify as wilderness: it's too small to meet the legal definition (being trammeled by the nearby houses, park, streets, and zoning rules), alien species abound, and there's too much human impact in the form of beer bottles, pop cans, plastic bags, or the occasional condom. What we have here is a mixed, ambiguous, and confusing landscape, yet one that is full of life and biotic diversity.

Why am I not drawn to study nature in such a landscape the way I am drawn to study it in the mountains, the desert, or the canoe country? The same chlorophyll, after all, makes the green world green no matter where it grows. Part of the reason may lie in what Leo Marx calls "pastoral idealism," the deeply-embedded notion that "out there," apart from human society and its built environment, nature abounds in health, grace, and virtue. This notion, conceived by Greek poets and practiced by writers, artists, and idle aristocrats down through the centuries, lies at the root of much current environmental thought. It conveniently masks the consequences of an impersonal ecology while allowing us to revere nature at a distance. By displacing all categories of value, such as beauty, truth, harmony, virtue, or health, from "right here" where we live to "out there" where we vacation or dream of retiring, pastoral idealism permits us to love the green world while carrying on the usual business of clearing, mining, logging, plowing, or paving it, all in the name of progress or development. As long as we have shrines like Yosemite, Yellowstone, or the Grand Canyon glowing on the horizon of desire, we can trash Cincinnati with lighter hearts. We can have our nature and eat it too.

But urban landscapes serve as a constant reminder. And this reveals a more sinister form of resistance. Every time I walk past the unmowed lot with its blue chicory, dandelions, and thickets of amur honeysuckle, I am reminded of how severely we humans have mauled the local ecology, driving away the animals, tearing up the ground, introducing all sorts of aggressive alien species. Once started down this path, it's hard to stop, hard not to think of the extermination of the buffalo, the decimation of prairie flora, the shaving and burning of ancient forests. The landscape begins to look like a world of wounds, and its history begins to look like a pattern of war, enslavement, and genocide, where all creatures are reduced to means for human ends regardless of their own ultimate concerns. These are not happy thoughts, nor are the feelings they evoke. It helps me repress them to think of this urban land as somehow less natural because it has been "impacted" or "spoiled." Maybe it's not really nature at all, not a real ecosystem, just a bunch of weeds and exotics mixed up with human junk. It doesn't count; it's not worth dealing with. I can ignore it. Such thinking makes urban nature invisible in a way that Ralph Ellison might have recognized. Beneath it lies the old desire to escape from history and avoid responsibility for our sins.

These are some forms of resistance I feel when pondering the very idea of urban nature. But resistance, as Zen masters know, is often a first step in learning. Historically, American environmentalism and its prophetic texts have drawn their inspiration from travels into the wild. We are pretty familiar with that sort of ground, but it is by no means the whole terrain. What can we learn from urban nature? Let's take a look at the matter of alien species.

Everyone knows that exotics abound in cities. Once mildly attuned to natural history, you begin to notice them everywhere. Many came as "stowaways" in sacks of feed or the ballast of ships; others were imported by gardeners but "escaped from cultivation."

The flower and bird books always make clear which species are native and which are alien. But why should it matter? In social terms, an alien is an outsider living on the inside, an "inside outsider," whereas a regular citizen is an "inside insider." An alien does not belong, yet is here. "Alien" in this sense is an official designation imposed by the group in power and thus, ipso facto, reflecting that group's values and social agenda.

In ecological terms, an alien is a species that arrived from somewhere else, that did not co-evolve with other resident organisms. More particularly we think of an alien species as one imported by humans, especially Europeans via the "Columbian exchange" that began with their incursions into the New World. An alien species does not belong in the native ecosystem, either because it has no original niche or because the niche it occupies did not exist until it arrived. Such species are bad because they "invade" and "take over" by "outcompeting" native species and "displacing" them from their niches or habitats. Alien species are also bad because they "degrade" the original ecosystem, or because they interfere with human activities, becoming "pests" or "noxious weeds." Examples abound: dandelions in the front lawn, amur honeysuckle in the woods, purslane in the garden, leafy spurge in the fields, purple loosestrife in the wetland. They are doing quite well, thank you, and they seem impossible to get rid of. Once they arrive, you can kiss wilderness, our standard of natural value, goodbye.

Interestingly, there's one kind of organism that's alien in both the social and ecological sense: I mean the aliens in science fiction. Another planet or galaxy represents the ultimate form of exotic landscape, and the behavior of space aliens is remarkably similar to that which we attribute to (or fear from) alien species on earth: they invade, run amok, and try to take over. Indeed, the plot often turns on heroic human efforts to defeat and annihilate the aliens, in order to "save the world." Things are made easier by the creatures' appearance, usually a hideous combination of features drawn from terrestrial nature. Typically, insects and parasites dominate this iconography of the grotesque, contributing body armor and slime. The fact that space aliens possess intelligence and technology, which we consider our exclusive property, makes their invasion not only threatening but scandalous. They must be stopped at all costs, because they come in and start doing to us what we have been doing to other creatures for years. They momentarily reverse the hierarchy in which humans dominate other creatures by right and by might.

The fact that space aliens are constructed out of pieces of earthly nature, and that these pieces are chosen from creatures we loathe or despise, suggests a scapegoating process. The invaders represent our own behavior stripped of all pretense to grace or virtue; you might say they're a caricature of how we must appear to other species. Of course, it is horrifying to be confronted with your own capacity for violence or evil, but it is equally horrifying to think that nature might not be committed to keeping us on top forever, might in fact have other ideas in mind, might want to sweep us off the stage in order to make room for new experiments. That the old order changeth, yielding place to new, is a classic lesson of evolution, but it is one that we cannot bear to entertain. As Annie Dillard says, evolution loves death more than it loves you or me. As a product of nature "out there," the invading alien embodies all the threatening power and creativity of an evolution indifferent to human desire. By defeating it in battle, human beings regain their dominance. The purpose of space alien fiction, then, is to assert a vision of human virtue and dominance over nature by scapegoating a constructed organism. The story of human victory naturalizes the status quo; the monster becomes an aberration blasted into the outer darkness; humans win, nature loses.

When we speak of humans here, we mean of course human as defined by the culture making the story. The constructed space alien shows how pervasively we desire to naturalize culture. The same process, I believe, informs our thought and behavior toward ecological aliens. We think of them as invading and running amok; we react with anger and hostility; we badmouth and belittle them while extolling the native; we try to extirpate them while reintroducing natives to "restore the ecosystem." You would think that alien species were posing a serious threat, that they would annihilate everything else if left to their own devices. You would think they were some kind of plague.

But a closer look suggests this may be simplistic thinking. Take my back yard for example: it's a flourishing array of native and non-native species. Of flowering herbs, I have native jewelweed, purple wood violet, daisy fleabane, avens, and blue-eyed grass; I have alien white clover, gill-over-the-ground, Indian strawberry, English plantain, and dandelion. Of trees, I have native beech, shagbark hickory, black tupelo, and northern pin oak; I have alien amur honeysuckle and glossy buckthorn. Of birds, I have native cardinal, bluejay, gold finch, mourning dove, junco, chickadee, nuthatch, and pileated woodpecker; I have alien starling, house finch, and house sparrow. The natives and aliens coexist; though the aliens do not dominate, they are here to stay. What this landscape presents is a flourishing hybrid community in which human activity plays a conspicuous role.

Interestingly, although alien species abound in the continental United States (numbering 6600 naturalized species and accounting for 5 percent of the biota, by some estimates), only a few are considered "serious invasives." Ecologists have developed a rough statistical guide known as the "Tens Rule" to describe this relationship. Generally speaking, for every thousand species introduced by any means into an area, one hundred will "escape" into the wild, ten will become naturalized, and one will spread far and fast enough to cause serious harm (which can mean either economic damage to business or agriculture, degradation of native ecosystems, or threats to the survival of native species). Hence, there should be about 660 alien species causing trouble even as we speak, a number roughly confirmed by particular studies, though conditions vary considerably from one location to another. The point is that not all aliens cause trouble, though all are tarred with the same brush in our thought and public discourse. Moreover, the definition of trouble reflects our economic, political, and cultural agenda rather than the ultimate concerns of the organisms in question.

When we talk about aliens "escaping from cultivation" or "becoming established in the wild," we are expressing frustration with the way imported organisms refuse to abide by their job descriptions. Amur honeysuckle, for instance, was brought to Cincinnati to serve as an ornamental shrub. Landscape architects admired its fondness for disturbed calcareous soils as well as its handsome foliage, long growing season, and abundance of fragrant white blossoms that mature into bright red berries. What they did not count on was the fact that these qualities also fitted it admirably to thrive in adjacent woods where, spread by the birds who love its fruits, it now forms dense stands that shade out both native wild flowers and the seedlings of canopy trees. No local insects appear to feed on it, nor does it suffer the usual plant diseases. The only ways to control it are to set fires in the woods, as the Indians did, or to pull it up by the roots, neither of which are practical on the large scales that are now required. As a result, succession has been interrupted in many of our woods, and some ecologists question whether the native forests can survive.

The "problem" of amur honeysuckle is not the plant's fault, of course. It is merely doing what any organism would under the circumstances: increasing and multiplying to replenish the earth and subdue it. Given ideal conditions, it will grow; it will express itself; it will flourish. This is the birthright and impulse of any life-form; call it wildness if you like. The problem, if there is one, lies with us human beings who created these favorable conditions and now refuse to accept full responsibility for management and control. We made the import decision based on our own esthetic and economic agendas, not to mention our limited ecological understanding of both the honeysuckle and the Cincinnati landscape. We wanted quick and limited results, impatient to circumvent the long horizons of evolutionary time that yield the "balanced" complexity of native ecosystems. Of course, succession of a new sort is now going on in our woods; evolutionary pressures are now affecting both the honeysuckle and its neighbors, toward results that no one can foresee. For evolution is an experiment that cannot be repeated. Like it or not, our woods will never be the same.

Ecological purists, however, talk of restoring the original community by uprooting all alien species and reintroducing natives. On a small scale, this can yield tantalizing results, but a closer look reveals troubling contradictions. At Fernald, just west of Cincinnati, a former uranium processing plant is being decontaminated, and an ecologist I know was asked to restore a twelve acre pasture on the site to its former wetland condition. Work began by scraping and grading the entire area, which was then stabilized with fiber mats and covered with topsoil; native plants were sown or transplanted; organic fertilizers were added, and the soil was inoculated with mycorrhizal spores. The plants came up in a textbook mosaic of indigenous flora, but problems arose almost at once. White-tailed deer browsed off the tender shoots; Canada geese uprooted aquatic plants and fouled the pond with their droppings; cattails muscled into the shallows. My friend spoke of fencing the area, stringing monofilament line across the pond to keep the geese from landing, and dipping a gloved hand in Roundup to poison individual cattails. The alternative, he said, was to keep replanting, which was unthinkable in time or cost. He admitted with some chagrin that the problem species were not exotics, but natives!

Urban nature reminds us that behind much ecological, political, and literary thinking lies a cherished concept of Edenic wilderness: a biotic community in equilibrium, sustainable, harmonious, and stable. Even though such a community might suffer occasional assaults from storm or fire, evolutionary time has guaranteed that all such disruptions will eventually be smoothed out. All resident organisms are considered to have fully coadapted; all niches are filled. This sort of thinking posits wilderness as a base datum of ecological normality, exemplifying what the land could and would produce if left to its own devices. The ecosystem is construed to embody a set of sustainable relationships that have proven survival value and can therefore be used as a standard of value for judging human actions and relationships, in other words, as the basis of an environmental ethic.

Significantly, this model casts human activity in a mostly negative light, as usurping, spoiling, tampering with, upsetting, or otherwise damaging the ecosystem—one notes, not incidentally, a certain similarity to the role of Eve in the myth of the Fall—and such actions are assumed to arise from ignorance, folly, greed, pride, or appetite. Humans, to paraphrase Dickens, are "naturally vicious." There is no room here for husbandry, responsible or otherwise. Nor is there room for the possibility that human actions might actually enhance the productivity of natural systems. Gary Nabhan has shown that small scale Papago farming increased biodiversity in the Sonoran desert oases of southern Arizona. When Organ Pipe Cactus National Monument was created, the farms were closed down and species began to disappear. Comparable examples can be drawn from the Boundary Waters of northern Minnesota, where the Ojibway increased berry and wildlife production using controlled burns, and from Amazonia, where the Mebêngôkre practice an intensive horticulture that builds soil, enhances biodiversity, and raises food and medicinal plants on hammocks in otherwise unproductive savannah. So subtle and refined are these methods that the Mebêngôkre gardens were not recognized as such until recently. They were thought to be wild productions of unassisted nature.

Beneath such Edenic thinking lurks the ancient idea of a "state of nature" where things grow and develop with no interference from civilized humans. The operative word here is "civilized," for the state of nature can and often did include people of various races and cultures that were considered barbaric, savage, or less advanced than that of the philosopher at the lectern. Before the seventeenth century, the state of nature was seen as a base line of development potential; it could be improved by art, cultivation, or education but not, apparently, degraded. Not until the romantic revolution in the late eighteenth century did the state of nature come to be seen as a repository of virtue, beauty, and inspiration that could, ipso facto, suffer diminishment and despoliation at the hands of people.

Either way, the state of nature was conceived to persist in its wild condition until and unless acted upon by civilized humans. In this sense it occupied a curious position with respect to time. It lay outside of history as defined by civilization, that is, as a series of irreplicable moments progressing linearly from past into future. Yet because it also participated in time, being subject to growth, death, and season change, it also lay outside of eternity, that is, outside the realm of the gods. The state of nature was temporal but ahistorical, rather like John Hanson Mitchell's "ceremonial time" of ritual and myth. Time moved but never progressed. More important, identity was intrinsic, not granted by the interplay between experience and character, as in human history. The process of individuation, the life story that we so take for granted, does not exist in the state of nature.

Natural history, therefore, appears as something of an oxymoron. It describes the life ways of organisms in a state of nature—even today, when the state of nature has been transmuted into the idea of wilderness—but the organisms are construed as types rather than individuals. (Think, for example, of the bird paintings of Roger Tory Peterson, which are constructed to showcase the field marks.) As discourse, natural history appears closer to myth than to biography because it deals with creatures as ahistorical icons. And its mythology is erected on a hierarchical separation of human culture from nature.

Of course, such views promise tempting returns. If human culture is considered superior to nature, as during the Renaissance, then humans can do what they like to it in the name of improvement or civilization. It is a short step from this charitable position to Baconian arguments for domestication, enslavement, or even extermination. The superior species', race's, or culture's agenda is naturalized and made to seem just and inevitable. On the other hand, if human culture is seen as inferior to nature, as it was by certain Romantic poets and American transcendentalists, then nature can be used as a concrete and accessible standard for judging people, cultures, or institutions. This view leads to the idealization of wilderness, the ethics of deep ecology, and, in extreme cases, a dream of reducing the human population by any means necessary.

But neither position is ultimately realistic or humane, and neither can lead to harmonious, just, or sustainable relations with the rest of the living world. The scandal of alien species is that they expose and subvert our received ideas about nature. For alien species are living proof that human and natural history cannot be disentangled, and that culture and nature are indissolubly linked. There is no such thing as an Edenic state of nature, no such thing as pure wilderness. Indeed, such concepts betray an ancient, troubling, and dysfunctional nostalgia for paradise, a desire to escape from history and deny responsibility for our violent and predatory treatment of other beings, not to exclude even members of our own species. What difference is there, except in degree, between "ethnic cleansing" and pulling weeds?

When I am oppressed by such thoughts, I find it refreshing to look out once again on my back yard, where alien and native species coexist in a flourishing, dynamic community. I do not know how this landscape will appear in a decade or a lifetime, what succession will emerge to shape its array of flowers and trees, but I do know it is something new for this continent and a great demonstration of the inexhaustible creativity of nature. How wonderful to find in the city, whose landscapes I used to despise, a scene of instruction as rich and fertile as any wilderness. I can learn as much from the English plantain at my feet as I can from a Parry primrose high in the Wind River Range.

Abram, David. The Spell of the Sensuous: Perception and Language in a More-Than-Human World. New York: Pantheon, 1996.

Alaimo, Stacy. "Discomforting Creatures: Monstrous Natures in Recent Films," in Karla Armbruster and Kathleen Wallace (eds.), Beyond Nature Writing. Charlottesville VA: University Press of Virginia, 2001.

Cox, George W. Alien Species in North America and Hawaii: Impacts on Natural Ecosystems. Washington DC: Island Press, 1999.

Dillard, Annie. Pilgrim at Tinker Creek. New York: Harper, 1974.

Marx, Leo. The Machine in the Garden: Technology and the Pastoral Ideal in America. New York: Oxford University Press, 1964.

Mitchell, John Hanson. Ceremonial Time: Fifteen Thousand Years on One Square Mile. Boston MA: Houghton Mifflin, 1984.

Nabhan, Gary Paul. The Desert Smells Like Rain: A Naturalist in Papago Indian Country. San Francisco CA: North Point Press, 1982.

Nelson, Richard K. Make Prayers to the Raven: A Koyukon View of the Northern Forest. Chicago IL: University of Chicago Press, 1983.

Posey, Darrell Addison, "The Science of the Mebêngôkre" in Peter Sauer (ed.), Finding Home: Writing on Nature and Culture from Orion Magazine. Boston MA: Beacon Press, 1992.