Depletion and Conservation of Natural Resources - Biodiversity

Biological diversity, or biodiversity, refers to the full range of plant, animal, and microbial life and the ecosystems that house them. Environmentalists began using the term during the 1980s when biologists increasingly warned that human activities were causing a loss of plant and animal species.

Studies of deforestation have supported the concerns about declining biodiversity, showing that tropical rain forests have dwindled from 3.5 billion acres before the industrial era to fewer than two billion acres. Deforestation has meant extinction for hundreds of species of plants and animals each year. The exact number of species in the remote forests is unknown, although it is generally accepted that they house the greatest number of species on the planet.

Extinction Rates

No one knows how many species of plants and animals exist in the world. By the beginning of the twenty-first century scientists had named and documented 1.4 million species. Educated guesses of the total number of different species range from five million to 100 million. Just as the health of a nation is promoted by a diverse economy, so the health of the biosphere is promoted by a diverse ecology.

Widespread extinctions have occurred infrequently in Earth's history and are generally believed to have been due to major geological and astronomical events. Scientists call the disappearance of only a few species over the period of a million years a "background rate." When that background rate doubles for many different groups of plants and animals at the same time, a mass extinction is taking place.

THE SIXTH EXTINCTION?

At least five times in the last 600 million years planet-wide cataclysms, such as drastic climate change or colliding asteroids, have wiped out whole families of organisms. Because of these losses scientists believe that more than 95 percent of all species that have ever existed are extinct. Researchers predict that, as tropical ecosystems are converted to farms and pasture, the extinction rate will approach several hundred extinctions per day before the mid-twenty-first century—millions of times higher than the background rate. The Worldwatch Institute believes that more species of flora and fauna may disappear in our lifetime than were lost in the mass extinction that included the disappearance of the dinosaur 65 million years ago.

The loss of diversity leads to problems beyond the simple loss of animal and plant variety. When local populations of species are wiped out, the genetic diversity within that species that enables it to adapt to environmental change is diminished, resulting in a situation of "biotic impoverishment." Those organisms that do survive are likely to be hardy, "opportunistic" organisms tolerating a wide variety of conditions—characteristics often associated with pests. Experts suggest that, as some species dwindle, their places may be taken by a disproportionate number of pest or weed species that, while a natural part of life, will be less beneficial to human beings.

Most living species have never been identified. Mammals, including humans, make up barely three-tenths of 1 percent of all known organisms. There were 1,263 species in the United States listed as endangered or threatened as of April 2004. Another 558 species are listed for foreign countries. (See Table 9.1.) The number of endangered or threatened species listed in the Unites States has increased dramatically since 1980 when less than 300 species were listed.

Scientists participating in the "Global Biodiversity Strategy," an international team of 500 researchers, believe that the extinction of species will deprive future generations of new medicines and new strains of food crops. With as many as 50 plant species disappearing daily, the researchers calculate that the planet's diversity

TABLE 9.1
Summary of listed endangered and threatened species, as of April 1, 2004

	Endangered		Threatened
Group	U.S.	Foreign	U.S.	Foreign	Total species
Mammals	69	251	9	17	346
Birds	77	175	14	6	272
Reptiles	14	64	22	15	115
Amphibians	12	8	9	1	30
Fishes	71	11	43	0	125
Clams	62	2	8	0	72
Snails	21	1	11	0	33
Insects	35	4	9	0	48
Arachnids	12	0	0	0	12
Crustaceans	18	0	3	0	21
Animal subtotal	391	516	128	39	1074
Flowering plants	569	1	144	0	714
Conifers and cycads	2	0	1	2	5
Ferns and allies	24	0	2	0	26
Lichens	2	0	0	0	2
Plant subtotal	597	1	147	2	747
Grand total	988	517	275	41	1821
SOURCE: "Summary of Listed Species—Species and Recovery Plans as of 4/1/2004," in Threatened and Endangered Species System (TESS)—Listed Species Summary (Boxscore), U.S. Department of the Interior, U.S. Fish and Wildlife Service, Washington, DC, April 12, 2004 [Online] http://ecos.fws.gov/tess_public/TESSBoxscore?format=display&type=archive&sysdate =4/01/2004 [accessed April 12, 2004]

could be reduced by 10 percent by 2015. One-fourth of all medical prescriptions in the United States contain active ingredients from plants. Among the medically useful species are some used in the treatment of cancer, Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS), circulatory disorders, bacterial infections, anxiety, inflammatory diseases, and for the prevention of organ rejection in transplants.

Species Loss—Crisis or False Alarm?

As with most environmental questions, not all experts agree about the threat to species diversity. Some observers believe that extensive damage to species diversity has not been proven and claim that, while wild habitats are disappearing because of human expansion, the seriousness of the extinction has been exaggerated and is unsupported by scientific evidence. They point to the fact that the total number of species and their geographic distribution are unknown. How, they ask, can forecasts be made based on such sketchy data?

Other observers contend that extinctions, even mass ones, are inevitable and occur as a result of great geological and astronomical events that humans cannot affect. They do not believe that disruptions caused by human activity are enough to create the mega-extinction prophesied by people they consider "alarmists."

Furthermore, some critics of the environmental movement believe that the needs of humans are being made secondary to those of wildlife. They contend that the Endangered Species Act protects wildlife regardless of the economic cost to human beings. Sometimes, as in the case of the spotted owl of the Pacific Northwest forests, that cost is the loss of jobs for people. The owl's presence halted logging there—following protests by environmental groups—at considerable economic loss to communities and families in the area. Furthermore, critics contend that halting development because it threatens a species whose whole population occupies only a few acres and numbers only in the hundreds is simply nonsense.

According to a 1998 poll conducted for the American Museum of Natural History by Louis Harris and Associates, biologists overwhelmingly view the loss of biodiversity as a serious problem. According to the survey, most scientists agreed that, if trends continue, the loss of species will have a very negative effect on the Earth's ability to recover from both natural and human-made disasters.

Earth Summit Biodiversity Treaty

At the 1992 Earth Summit in Rio de Janeiro, 156 nations signed a pact to conserve species, habitats, and ecosystems. This Biodiversity Treaty is regarded as one of two main achievements of the United Nations Conference on Environment and Development, the other being a treaty on global warming. The Biodiversity Treaty makes nations responsible for any environmental harm in other countries produced by companies headquartered in their country.

One provision of the treaty concerns "biotechnology," a term referring to the ownership of genetic material. Plants, seeds, and germ plasm have historically been in the public domain (belonging to the general public), rather than belonging to any particular government. Therefore, anyone could exploit or use them without compensation to the country of origin. For example, the rosy or Madagascar periwinkle, a plant found only in the tropical rain forests of Madagascar, is used as a base for medication to treat Hodgkin's disease and childhood leukemia. Madagascar receives no compensation for use of the plant. The biotechnology treaty drafted in Rio called for compensation to be paid for the use of those genetic materials.

The United States did not sign the treaty at the time. The administration of George H. W. Bush, while agreeing with many provisions of the pact, believed the economic requirements for accomplishing those goals were unacceptable to American businesses because they would be forced to compensate for the use of these species. President Bill Clinton signed the treaty in 1994. However, as of April 2004 the treaty had not been ratified by the U.S. Senate.

Endangered Species Act

The 1973 Endangered Species Act (ESA), passed into law during the administration of President Richard Nixon, was originally intended to protect creatures like grizzly bears and whales with whose plight Americans found it easy to identify. In the words of its critics, however, it has become the "pit bull of environmental laws," policing the behavior of entire industries. In three decades the ESA has gone from being one of the least controversial laws passed by Congress, to one of the most contentious.

The ESA regulates industries that can cause fish and wildlife populations to decline. It also determines the criteria to decide which species are endangered. Since the act was first passed, the pendulum has periodically swung between increased protection and the need to soften the law's economic impact.

The U.S. Supreme Court, in Manuel Lujan, Jr., Secretary of the Interior v. Defenders of Wildlife et al. (504 US 55 1992), determined that groups and individuals cannot sue the government solely on behalf of the public interest or on behalf of the flora and fauna they seek to protect. Instead, they must demonstrate harm to themselves. The ruling has been generally regarded as a victory for business interests and a defeat for environmentalists in their efforts to protect endangered species, since immediate harm is often difficult to show in environmental issues.