|E. O. Wilson|
But what is Nature? The simplest possible answer is also the best: Nature is that part of the original environment and its life forms that remain after the human impact. Nature is all on planet earth that has no need of us, and can stand alone.
Some skeptics have insisted that even when elaborated, such a definition has little use, because the natural world has been so disturbed as to be humanized everywhere and thus has lost its original identity. There is a kernel of truth in that claim. Very few square kilometers of Earth’s land surface remain untrodden at some time or other, at the very least by explorers and native people….
It is further true that thousands of industrial pollutants drift continuously onto the receding polar snows and into the most distant seas. Five percent of Earth’s surface is burned every year, mostly in order to create agricultural fields or re-fertilize old ones. These practices and others contribute to the overloading the atmosphere with greenhouse gases, sufficient to destabilize the climates of the entire planet.
The humanization of Earth proceeds in many other ways. Most of the land-dwelling mega-fauna, comprising animals weighting ten kilograms or more, have been hunted to extinction on the land. Wildlife of the plains and forests of the world today bears little resemblance to the majestic parade of giant mammals and birds driven to extinction by expert Paleolithic hunters. A large minority of those surviving today are on the endangered list. Twelve thousand years ago the wildlife of the American plains was richer than of Africa today.
Overall, humanity had altered this planet as profoundly as our considerable powers permit. Yet a great deal of Nature does remain. In purest state it exists in what are still legitimately called wildernesses. Very roughly, a full-scale, mega fauna-sized wilderness is defined as relatively large and mostly undisturbed aggregate of habitats. As specified by Conservation International in a recent study, it is an expanse of ten thousand square kilometers (one million hectares) or more, at least 70 percent of whose area still bears natural vegetations. Domains of this magnitude include the great tropical forests of the Amazon Basin, the Congolian Basin, and most coniferous forests that stretch across North America and on through Siberia to Finnoscandia. Wildernesses of a very different kind are earth’s largest deserts, the polar regions, the high seas, and the abyssal floors of the oceans (in contrast, very few deltas and coastal waters remain unchanged).
Smaller wildernesses abound, denoted officially in the U.S. Wilderness Act of 1964 as parts of Earth “untrammeled by man and where man himself is a visitor who does not remain.” In this historic piece of legislation, 9.1 million acres were set aside “for the use and enjoyment of the American people in such a manner as will leave them unimpaired for future use and enjoyment.” Mandating protection of fragments as small as 5,000 acres, the act has saved such priceless tracts of land and water as Montana’s Great Bear Wilderness and the Allagash Wilderness Waterway of Maine.
Untrammeled. How well that word catches the spirit of wilderness! But how exactly it applies in practice depends on the scale employed. A suburban woodlot is obviously no longer a wilderness for mammals, birds, and trees. But it might be a “micro-wilderness” for small organisms. Many kinds of insects, mites, and other arthropods, mostly under ten millimeters in size, range freely there, their local domains untroubled by human hands, feet, or tools. Luckily, micro-wildernesses are not a trivial part of wild Nature. Quite the opposite: each cubic meter of soil and humus within it is a world swarming with hundreds of thousands of such creatures, representing hundreds of species. With them are even greater numbers and diversity of microbes. In one gram of soil, less than a handful, live on the order of ten billion bacteria belonging to as many as six thousand species.
The entire lives of the microscopic and barely visible organisms play out in spaces that human beings, among the largest animals on Earth, are inclined to dismiss. For an oribatid mite, only a crawling dot to the naked eye, a rotting tree stump is the equivalent of Manhattan. For a bacterium, the equivalent is New York State. The woodlot may be seriously disturbed on a macro-scale, as perceived by humans who walk across it in a few minutes. It may be littered with trash. Its trees may be second-growth. But around the base of each tree is an ancient and relatively intact miniature inhabitants. The soil and litter between the trees is their continent, and the nearby springtime pool is their sea.
* The above text is taken from E. O. Wilson, The Creation, Norton, 2006, pp. 15-17