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(ESA) is the nation's primary tool for preventing species extinctions. Congress intended the Act to function as a safety net, catching imperiled species before they are lost forever. In addition to preserving threatened and endangered species, one of the ESA's explicit purposes is to extend protection to at least a portion of the ecosystems upon which listed species depend. But the law was not designed to shoulder the entire burden of biodiversity conservation in the United States. Various other conservation laws, among them the 1969 National Environmental Policy Act, the 1972 Clean Water Act, the 1972 Coastal Zone Management Act,

Protection Act, the 1976 National Forest Management Act, the 1976 Federal Land Policy and Management Act and the 1976 Fishery Conservation and Management Act, include provisions that protect species and habitats. If these laws were fully implemented, there would

be less need for an ESA because there would be fewer endangered species. Instead, the ESA increasingly has been pressed into service for crisis management.

Saving Living Systems

Extinction is often the gradual and cumulative result of a number of common, daily activities. Taken alone, the construction of an additional suburb, the

clearing of another acre of forest or the catching of an additional net full of fish might have little impact on total species populations. But the accumulated pressures of habitat loss, overexploitation, pollution and other small, daily tinkering with the natural environment result in the slow, steady dwindling of even common species. As a result, the planet is losing species faster than at any other time in human history. The ESA helps to mitigate this trend by seeking to assure the survival of the life forms with

which we share the planet, from great whales and majestic eagles to often-overlooked plants scattered across the forest floor. The ESA protects all these for the benefit of all the inhabitants of

this world, including humans. Aldo Leopold, the father of wildlife management, warned five decades ago that the first rule of intelligent tinkering is to save all the pieces.'

Benefits of Biodiversity

On a rainy September day in 1914, the world's last passenger pigeon died at the Cincinnati Zoological Gardens. A remark

ably popular game species, the passenger pigeon was once the most numerous bird in North America, if not the world, the size of its population almost beyond comprehension. Eyewitnesses reported vast flocks of the birds darkening the sky for hours, and the distinguished artist and ornithologist John James Audubon likened the cumulative roar of their wings to “a hard gale at sea, passing through the rigging of a closereefed vessel." Early in the 19th century, the species may have numbered some 4 billion birds, but unrestrained market hunting, combined with habitat loss, decimated the pigeon population until only a single, captive speci

men remained, a fragile reminder of the vast flocks that had been one of the world's greatest natural spectacles. Only a few months after the last passenger pigeon died, the species was joined in extinction by the Carolina parakeet, a denizen of the Southeast that was one of only two parrot species native to the United States. The parakeet was another victim of habitat loss and uncontrolled hunting.

In the 19th century, commercial hunting played a major role in the extirpation or near extirpation of many species killed for meat or hides, including the bison, pronghorn, elk and bighorn sheep. Since then, habitat destruction has replaced hunting as the leading cause of extinction. But unlike commercial

hunting, which usually targets individual species, habitat destruction affects virtually all the species that share a common area. As development across the world has accelerated, so has the rate of habitat loss and the rate of extinction. Biological diversity, the sum total of all the different and unique forms of life on the

planet and their interrelationships is now threatened by a wave of extinction unparalleled since the end of the of the age dinosaurs 65 million years ago.

The recent surge in the global extinction rate coincides directly with the rise of industrial society. Although extinctions occur naturally as a consequence of evolution. The natural extinction rate is a tiny fraction of the current extinction rate. Humans have accelerated the natural extinction rate by hundreds if not thousands of times, threatening the very fabric of ecological systems. Scientists estimate that the planet may be losing up to 50,000 species per year. Although data suggest that losses are occurring most rapidly in tropical rainforests, habitat in the United States is also seriously affected. During the last 200 years, more than 500 species of plants and animals native to the United States have vanished 250 of them since 1980, according to the U.S. Fish and Wildlife Service (FWS). The span of just three human lifetimes has witnessed the permanent loss of

Grizzly Bear (Continued)

conflict with land uses such as recreation, timber harvest and livestock grazing.

In 1993, Defenders joined the effort to reintroduce grizzlies in the Bitterroot ecosystem. Defenders is raising the visibility of the project through educational campaigns and media work in order to build broad public support and to counter fears and misunderstanding that may stand in the way of the recovery effort. In addition, Defenders is working to obtain funding for an environmental impact statement, a necessary first step in the recovery process.

more than one percent of U.S. flowering plants, two percent of U.S. birds and amphibians and 13 percent of U.S. freshwater mussels. According to The Nature Conservancy's Natural Heritage Data Center, more than 30 percent of the nation's 16,300 species of native vascular plants are now of conservation concern, along with 22 percent of America's 2,500 native vertebrates.

The United States and the world as a whole are poised on the brink of a biological tragedy that could fundamentally alter human society and the basis of all remaining life on the planet. Noted biologist Edward O. Wilson has estimated that if cur

rent trends continue, we will lose or doom to extinction within the next 30 years a fifth of the world's species. The loss of literally millions of distinct kinds of plants and animals, a massive pauperization of the planet's biological resources, would rival the greatest extinctions of the past 500 million years - extinctions from which the planet required over 10 million years to recover. As Wilson has said, "This is the folly our descendants are least likely to forgive us.”

Despite technological advances, people are still tightly bound to natural systems. The relationship between humans and the rest of the biological

world is complex and multifaceted, and the current extinction crisis can harm humans in numerous ways. The ESA is now the nation's chief vehicle for conserving biodiversity and for safeguarding society from the effects of its loss-effects that would be profound, as the following discussion suggests.

Agriculture

We rely on the natural world for our food supply. All agricultural crops must be bred periodically with wild varieties to increase yields and even to main

tain current levels of production. Although today's modern highyield hybrid plant crops are bred

for disease-resistance, after five to 15 years genetic resistance fades as new strains of disease adapt to plant defenses, leaving entire crops vulnerable.' In the 1970s, for example, a corn blight struck the southeastern United States and wiped out more than a seventh of the nation's corn crop, costing farmers and consumers in excess of $2 billion."

Wild relatives of commercial plant varieties, found primarily in natural areas, often are resistant to the diseases that trouble

domestic crops. This makes wild species key to maintaining crop health and diversity. In 1977, researchers discovered in Mexico a wild variety of corn that was resistant to the seven major types of viral disease that usually infect commercial corn. The potential economic benefits of this discovery are staggering: a mere one percent increase in corn production as a result of increased disease resistance would add $150 million to $200 million to the annual value of the U.S. corn crop.' Overall, this single discovery may be worth billions of dollars to American agriculture.

Crossbreeding crop plants with wild relatives also can provide other benefits to food production, from more nutritious soybeans to strains of barley and tomatoes that can be irrigated with seawater. The worldwide destruction of natural areas threatens many vital wild varieties of plant with imminent extinction. The wild Mexican corn plant that so benefited the agricultural industry grows in only three small patches. A single bulldozer could easily wipe out the entire species in less than an hour. Without these wild varieties, the agricultural industry may be unable to produce sufficient food to provide for exploding human populations in the next century.

Wild species are also a major source of new curative drugs. More than 40 percent of the prescriptions filled in the United States each year are derived from plants, animals and microbes. These drugs form the backbone of the American pharmaceutical industry, which contributes more

than $60 billion to the nation's economy annually. 10 Yet only a small fraction of the world's species have been screened for potential use as curative drugs. Overall, flowering plants have been the most closely examined group, yet fewer than three percent of such plants - 5,000 species out of 220,000 worldwide - have been examined for medi

cinal compounds."

The rosy periwinkle of Madagascar provides a good example of the potential that wild plants hold for curing humanity's worst diseases. Two compounds derived from this innocuous little plant have proved successful in treating Hodgkin's disease and childhood leukemia.

Although the species-rich tropics are often described as "nature's pharmacy," many species found in the United States also hold great potential for drugs. Digitalis, a drug derived from the common purple foxglove, is used by 3 million Americans annually to treat heart disease, and aspirin, the most widely used medicine in the