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The evolution time bomb.

National parks and other protected areas may hold the key to survival of species...including our own.

THE TRADITIONAL FUNCTION of parks has been to provide inspiration, recreation, and resource protection. But today parks must serve a new role as well, one we are just beginning to understand, and one that could help humanity survive the consequences of its own actions.

Ample evidence exists to suggest that humankind is interrupting the Earth's natural ability to heal. But for perhaps the first time in evolutionary history, the most dominant force affecting change has the potential to control its impact. The nine-mile-wide meteor that is believed to have caused the extinction of the dinosaurs could no more stop its trajectory toward the planet than a volcano could stop its eruption, but humankind has the ability to make constructive choices to halt the loss of species. And national parks can, and must, play a crucial role toward this end.

Our parks, forests, and refuges hold the keys to species's survival, including our own. Although in the past not much attention has been paid to the crucial role parks play in preserving the habitat necessary for any species' survival, they are the only areas we have that come close to being large enough to support natural selection and evolution. And these areas may need to be even larger to ensure the long-term survival of many of the species in the parks, as suggested by noted biologist Michael Soule.

Despite the important role national parks and other protected lands play, not enough research is conducted with long-term public objectives in mind. These areas are perhaps the only places left that can serve as laboratories to teach us how to cope with acid rain, ozone exposure, industrial pollution, global warming, and toxic runoff. In the past, the national parks have not had an organized endangered species program except in isolated cases, and there is limited integration of research within a park or refuge, let alone among management units.

The newly proposed federal Biological Survey program shows promise for the national parks; however, in addition to a concomitant purpose for research, these habitats must be protected to ensure survival of species and of the evolutionary process.

As part of international environmental goals, each nation has agreed to strive to protect as parkland at least 5 percent of its land mass--a goal that the United States has yet to meet. The United States has set aside roughly 170 million acres of its 3.6 billion square miles as national parks and wildlife refuges, land that could be called protected habitat. This total does not include land within the national forests, still under the control of the Department of Agriculture, which has only a token commitment toward preservation, nor does it include a representation of all of the types of ecosystems found in this country.

We know that evolution is the process by which all living organisms' chances of survival are enhanced in a changing world. These natural changes have occurred for millions of years, creating the untold numbers of species that exist now and have existed in the past. Unfortunately, however, humankind has accelerated the rate of change and disturbed and manipulated the environment to such a degree that the ingredients necessary for evolution as described by Darwin are disappearing, endangering the process itself.

Scientists project that 15 million species will vanish in the next few decades because of destruction wrought by Homo sapiens. In the United States alone, more than 600 species are listed by the federal government as endangered. Of that number, recent studies indicated 38 percent were improving. More than 3,000 "candidate species" are waiting to be listed.

Scientists also predicted that the rapid rate of climate change--brought on by an increase of carbon dioxide from automobiles and other industrial pollution--will inhibit, if not prohibit, the ability of trees and plants worldwide to adapt. Trees are weakened by pollution, subjected to water diversion, and attacked by natural and exotic diseases and insects. Witness the loss of the American chestnut and the slow disappearance of the American dogwood.

Everywhere, species are coming under increasing stress from pollution, habitat change, competition, exploitation, and predation from introduced, alien species. Elsewhere in the world, the same patterns are emerging, whether the nation is "developed" or "developing." If stressed species are to survive, natural selection must be allowed to assist them in adapting to changing conditions. Scientists such as Soule and Mark Shaffer have shown that for such adaptations to occur, threshold levels of population and habitat size must be achieved. If the numbers of individuals are not sufficient, extinctions become more likely.

One way to understand what has happened to Earth's biological diversity is to look at Madagascar, a developing country, which is probably the richest biological environment on the planet. There are 150 species of frogs alone, 148 found only on the island. There are 40 kinds of lemurs, 160 genera of palms. The plants and animals of this island nation off the east coast of Africa evolved for more than 180 million years without Homo sapiens' influence. Then, about 1,000 years ago, traders settled the island and thus began the extermination of species. Population growth, poaching, the demand for firewood, destructive agriculture practices, and other human actions continue to take a toll.

Today, less than 10 percent of the forest habitat remains, and that small area is under constant pressure. In effect, it is reasonable to conclude that humans have stopped the evolution of Madagascar's plants and animals by eliminating their habitat, by polluting the waters the species depend on, and by cutting up the ecosystems into tiny "islands" with few connecting corridors.

Survival of species is not an esoteric issue, such as the spiritual benefit of a beautiful landscape. Daniel Janzen, professor of biology at the University of Pennsylvania, is already working with the people of Costa Rica to understand the benefits that could be derived from the more than 500,000 species of plants and animals that live in this Central American country. Any knowledge gleaned through this research effort will be made available to pharmaceutical companies and scientific communities to provide both health and economic benefits to Costa Ricans.

And there are many discoveries to be made. Of 1,500 plants from Costa Rican rainforests, 225 of them could produce life-saving drugs. Yet, we are still burning rainforests at such an alarming rate that we may never know what species we have lost, let alone understand how they evolved. Along with the loss of species will be the loss of knowledge that could benefit humanity, and this may be the greatest loss of all. For example, the Pacific yew of our Northwest was treated as a "trash" tree until it was found to contain taxol, an ingredient that has proved effective in treating cancer.

The 21st century may well be a time when millions of plant and animal species are no longer vigorous enough to adapt naturally to change or to undergo splitting into additional speciation), let alone survive.

How do we ensure survival of species and allow for their continued evolution? We cannot do it by collecting all endangered species in zoos or botanical gardens. Although these are valuable locations for human understanding and study, they do not have the resources to propagate the plants or breed the thousands of vertebrate and millions of invertebrate species that are becoming endangered.

The only way to ensure survival of species and continuation of evolution is to preserve sufficient habitat. Even if critics do not agree with saving each and every species, they cannot argue with the logic behind the prudent philosophy that the art of intelligent tinkering begins with saving all the pieces. Our survival and quality of life depend on it.
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Copyright 1993 Gale, Cengage Learning. All rights reserved.

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Title Annotation:national parks' role in preserving endangered species
Author:Pritchard, Paul C.
Publication:National Parks
Date:Jul 1, 1993
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