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Preserving Biodiversity Is Protecting Life on Earth : Environment: Why care about red squirrels, tundra, blue beetles or little bluestem grasses? Three reasons, which boil down to self-interest.

May 13, 1990|Donella H. Meadows | Donella H. Meadows is an adjunct professor of environmental and policy studies at Dartmouth College

PLAINFIELD, N.H. — The ozone hole and the greenhouse effect have entered our public vocabulary, but we have no catchy label for the third great environmental problem of the late-20th Century. It's even more diffuse than depletion of the ozone layer or global warming, harder to grasp and summarize. The experts call it "the loss of biodiversity."

Biodiversity obviously has something to do with pandas, tigers and tropical forests. But preserving biodiversity is a much bigger job than protecting rainforests or charismatic megafauna. It's the job of protecting all life--microscopic creepy-crawlies as well as elephants and condors--and all life's habitats--tundra, prairie and swamp as well as forests.

Why care about red squirrels, for instance?

"Do we have to save every subspecies?" asked the U.S. Interior secretary, Manuel Lujan Jr., on Thursday. He called for changes in the Endangered Species Act, because it is blocking construction of a $200-million telescope on Mt. Graham in Arizona, the habitat for about 180 endangered red squirrels.

Why care about tundra, swamp, blue beetles or little bluestem grasses? Ecologists give three reasons, which boil down to simple self-interest on three levels of escalating importance.

Biodiversity has both immediate and potential economic value. This is the argument most commonly put forward to defend biodiversity, because it's the one our culture is most ready to hear. It cites the importance of the industries most directly dependent upon nature--fisheries, forestry, tourism, recreation and the harvesting of wild foods, medicines, dyes, rubber and chemicals.

Some ecologists are so tired of this line of reasoning that they refer wearily to the "Madagascar periwinkle argument." That obscure plant yields the drugs vincristine and vinblastine, which have revolutionized the treatment of leukemia. About a third of all modern medicines have been derived from molds and plants. The potential for future discoveries is astounding. The total number of species of life is somewhere between 10 million and 30 million, only 1.7 million of which we have named, only a fraction of which we have tested for usefulness.

The economic value of biodiversity is very real, but ecologists hate the argument because it is both arrogant and trivial. It assumes that the Earth's millions of species are here to serve the economic purposes of just one species. And even if you buy that idea, it misses the larger and more valuable ways that nature serves us, even if we never name or harvest its millions of species.

Biodiversity performs environmental services beyond price. How would you like the job of pollinating all trillion or so apple blossoms in New York state some sunny afternoon in late May? It's conceivable, maybe, that you could invent a machine to do it, but inconceivable that the machine could work as elegantly and cheaply as the honeybee, much less make honey on the side.

Suppose you were assigned to turn every bit of dead organic matter, from fallen leaves to urban garbage to road kills, into nutrients that feed new life. Even if you knew how, what would it cost? A host of bacteria, molds, mites and worms do it for free. If they ever stopped, all life would stop. We would not last long if green plants stopped turning our exhaled carbon dioxide back into oxygen. Plants would not last long if a few genera of soil bacteria stopped turning nitrogen from the air into nitrate fertilizer.

Human reckoning cannot put a value on the services performed by the ecosystems of earth. In addition to pollination and nutrient recycling, these services include the cleansing of air and water, flood control, drought prevention, pest control, temperature regulation and maintenance of the world's most valuable library--the genes of all living organisms.

Biodiversity contains the accumulated wisdom of nature and the key to its future. If you ever wanted to destroy a society so thoroughly that there would be no hope of its resuscitation, you would burn its libraries and kill its intellectuals. You would destroy its knowledge. Nature's knowledge is contained in the DNA within living cells. The variety of that genetic information is the driving engine of evolution, the immune system for life, the source of adaptability--not just the variety of species but also the variety of individuals within each species.

Individuals are never quite alike. Each is genetically unique mostly in subterranean ways that will only appear in future generations. We recognize that is true of human beings. Plant and animal breeders recognize it in dogs, cattle, wheat, roses, apples. The only reason they can bring forth bigger fruits or sweeter smells or disease resistance is that those traits are already present in the genes carried by some individuals.

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