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Ch. 9: Sustaining Biodiversity: The Species Approach

Terms in this set (62)

Species are a Vital Part of the Earth's Natural Capital.

1) The world's species are a vital part of the earth's life support system. They provide natural resources and natural services that keep us and other species alive. For example, we depend on some
insects for pollination of food crops and on some birds for natural pest control. Each species also has ecological value, because it plays a role in the key ecosystem functions of energy flow and chemical cycling, in keeping with one of the three principles of sustainability. Thus, by eliminating species, especially those that play keystone roles, we can upset ecosystems and speed up the extinction of other species that depend on those systems. Eventually such degradation of the earth's natural capital can threaten human health and lifestyles. Thus, by protecting species from extinction caused by human activities, and by protecting their vital habitats from environmental degradation, we are helping to sustain our own health and well-being.
2) ECONOMIC SERVICES THAT SPECIES PROVIDE: when we lose them, we can't get those services anymore. most species contribute to economic services—those services that support our economies (Concept 9-2). For example, various plant species provide economic value as food crops, fuelwood and lumber, paper, and medicine. Bioprospectors search tropical forests and other ecosystems to find plants and animals that scientists can use to make medicinal drugs. According to a 2005 United Nations University report, 62% of all cancer drugs were derived from the discoveries of bioprospectors. Despite their economic and medicinal potential, less than 0.5% of the world's known plant species have been examined for their medicinal properties. green Career: Bioprospecting - Species diversity also provides economic benefits from wildlife tourism, or ecotourism, which generates more than $1 million per minute in tourist expenditures. Conservation biologist Michael Soulé estimates that a male lion living to age 7 generates about $51 5,000 in tourist dollars in Kenya, but only about $1 ,000 if killed for its skin. Similarly, over a lifetime of 60 years, a Kenyan elephant is worth about $1 million in ecotourism revenue. This is much more than what could be gained from the illegal sale of ivory obtained by killing an elephant and removing its tusks. Ecotourism is thriving because people enjoy wildlife.
3) Caring for future generations: analysis of past mass extinctions indicates it will take 5 million to 10 million years—25 to 50 times longer than the amount of time that our species has been around—for natural speciation to rebuild the biodiversity that is likely to be lost during this century. As a result, any grandchildren that you might have along with hundreds of future generations are unlikely to be able to depend on the life-sustaining biodiversity that we now enjoy.
4) Ethical Obligation: many people believe that each wild species has a right to exist, regardless its usefulness to us. According to this view, we have an ethical responsibility to protect species from becoming extinct as a result of human activities and to prevent the degradation of the world's ecosystems and their overall biodiversity. This ethical viewpoint raises a number of challenging questions. Since we can't save all species from the harmful consequences of our actions, we have to make choices about which ones to protect. Should we protect more animal species than plant species and, if so, which ones should we protect? Some people support protecting well-known and appealing species such as elephants, whales, polar bears, tigers, and orangutans. But they care much less about protecting plants that serve as the base of the food supply for all species. Other people distinguish among various types of species. For example, they might think little about getting rid of species that they fear or hate, such as mos-quitoes, cockroaches, disease-causing bacteria, snakes, and bats. Some scientists argue that the current extinction crisis is tragic, partly because we do not even know what we are losing. No one has ever seen or studied many of the species that are rapidly becoming extinct. To biologist Edward O. Wilson, carelessly and rapidly eliminating species that make up an essential part of the world's biodiversity is like burning all the copies of millions of books that we have never read.
Critics of the ESA call it an expensive failure because only 46 species have been
removed from the endangered list. Most
biologists insist that it has not been a failure, for four reasons:

1) Species are listed only when they face serious danger of extinction. Arguing that
the act is a failure is similar to arguing that a poorly funded hospital emergency room set up to take only the most desperate cases, often with little hope for recovery, should be shut down because it has not saved enough patients.

2) It takes decades for most species
to become endangered or threatened. Not
surprisingly, it also takes decades to bring a species in critical condition back to the point where it can be removed from the critical list. Expecting the ESA—which has been in existence only since 1973—to quickly repair the biological depletion that took place over many decades is unrealistic.

3) According to federal data, the conditions of more than half of the listed species are stable or improving, and 99% of the protected species are still surviving. A hospital emergency room taking only the most desperate cases and then stabilizing or improving the conditions of more than half of those patients while keeping 99% of them alive would be considered an astounding

4) The 2010 budget for protecting
endangered species amounted to an average expenditure of about 9¢ per U.S. citizen. To its supporters, it is amazing that the ESA, on such a small budget, has managed to stabilize or improve the conditions of more than halfof the listed species.