What areas are the most important to preserve

Questions of "conservation triage" are difficult, but they must be faced in a world of limited support for conservation agendas. Faced with this problem, British ecologist Norman Myers devised the concept of biological "hotspots," which he defined as regions particularly rich in endemic species and immediately threatened by habitat destruction. Myers is the author of 17 books on the environment, among them Gaia: An Atlas of Planet Management, 1993. Myers listed 25 particularly important hotspots, which total only 1.4% of the earth's land surface, but contain 44% of all plant species and 35% of all terrestrial vertebrate species. The Indo-Burma hotspot covers

An ecotourist sits watching a highly endangered baby mountain gorilla (Gorilla beringei beringei) as it rolls on its back over flattened shrubbery. (Photo by © Staffan Widstrand/Corbis. Reproduced by permission.)

approximately 795,000 mi2 (2,060,000 km2) in south and Southeast Asia, and is home to such threatened species as tigers (Panthera tigris), red-shanked douc langurs (Pygathrix nemaeus), Sumatran and Javan rhinoceros (Dicerorhinus sumatrensis and Rhinoceros sondaicus), and Eld's deer (Cervus eldi). However, only 61,780 mi2 (160,000 km2), or 7.8% of the total area, is protected. Myers's favored strategy would be for conservation organizations to focus their efforts for fundraising and biodiversity conservation upon these areas, and such organizations as Conservation International and the MacArthur Foundation now largely subscribe to the hotspot approach.

However popular it may become, hotspot triage is not without its problems and detractors. For example, some readers may be surprised to learn that rainforests in the Amazon and Congo Basins do not make the magic Top-25. These areas, of course, are rich in endemic species—but they maintain over 75% of their forest cover and are in no immediate danger of complete destruction. Hotspot advocates would argue, "We should spend scarce dollars on species-rich real estate that's about to be destroyed." Opponents might reply, "I'd rather spend scarce dollars on species-rich Amazonia while I can still afford a really big chunk of it."

Regardless of her or his affection for (or disaffection with) hotspot triage, any mammalogist concerned with long-term conservation should become familiar with the types of habitats most important to mammalian diversity and most severely threatened with destruction. Such habits include tropical rainforests, tropical deciduous forests, grasslands, mangroves, and aquatic habitats.

During the 1980s and 1990s, tropical rainforests captured an increasing share of public attention. Rainforests cover less than 2% of the earth's surface, yet they are home to over 40% of all macroscopic life forms on our planet—as many as 30 million species of plants and animals. Rainforests are quite simply the richest, oldest, most productive, and most complex ecosystems on Earth. Furthermore, many of them, particularly in Asia and Oceania, are increasingly threatened by destruction.

An entangled northern fur seal (Callorhinus ursinus) is held down by an Aleut teen and seal biologist to remove fishnet that would kill the animal. (Photo by YVA Momatiuk & John Eastcott/Photo Reserachers, Inc. Reproduced by permission.)

Because they are more amenable to sedentary agriculture, some tropical deciduous forests are even more severely threatened than rainforests. Tropical savannas, with their magnificent relics of the Pleistocene mammalian megafauna, are easily converted into pasturelands—and unspoiled tropical savannas scarcely exist at all outside of formal National Parks. Mangroves, which shelter a number of important mammalian species, such as proboscis monkeys (Nasalis larvatus), are threatened by pollution, conversion for intensive aquaculture, and destruction for firewood. Lakes, rivers, estuaries, sea-coasts, and other aquatic habitats are also under increasing threats of multiple dimensions.

A problem faced by most conservation biologists working in the international arena is that countries with the highest degree of biodiversity (and this is particularly true for threatened and endangered mammals) are usually the countries least able to afford the conservation of their natural resources. For example, in some areas the median per capita income is less than $1US per day. People living under these conditions often consider conservation to be an unafford-able luxury.

Of course conservation biologists have long recognized that the futures of tropical peoples and of tropical wildlife are inextricably mixed. And for more than a decade almost all conservation action plans have emphasized the fact that local people should have an economic stake in the protection of their wild resources. Zimbabwe's "Campfire" program provides a classic example of the local benefit philosophy in action. Village councils were given authority to manage wildlife resources. Then, for example, when Europeans or Americans came to Zimbabwe to kill elephants, the villages could profit from the substantial expenditures of the wealthy hunters. Unfortunately, Campfire (and related "eco tourism" plans) is selling a high dollar luxury activity—which is at the mercy of international market forces and local interference. International economic downturns or national instability (both of which have beset Campfire) can undermine value-added conservation programs.

Under some circumstances sustained-yield harvest programs that return valued wild products directly to local users can be successful. Nevertheless, among people who are desperately poor, the odds against such programs are high. Many impoverished people naturally think of wild mammals as meat—not as an abstract food-resource to be harvested on a long-term, sustained-yield basis but as meat, now, for children who will otherwise be far too hungry before nightfall. The sale of bushmeat is rapidly becoming a substantial source of income, as well.

Because many conservation biologists believe that local biodiversity is a universal good, some argue that wealthier nations (and individuals) have a moral duty to assist poorer nations in conserving humanity's general biodiversity heritage. Even if one subscribes to this idea, it is difficult to determine (particularly on personal, financial levels) the degree of sacrifice that is morally obligatory. Furthermore, in recognizing that severe poverty threatens conservation, there are two more fundamental facts:

• First, severe poverty is in part a function of inequality. In 2003 the United States contains about 5% of the world's people—but is responsible for 30% of the world's resource-consumption. It is difficult for Americans to preach conservation to the rest of the world until the United States begins to clean up its own house.

• Second, severe poverty is in part a function of population-size. If the economic "pie" is finite in size, then even if the pie were equitably shared, "more people" would mean "smaller pieces per capita." At some point, population control becomes a prerequisite to effective conservation policy.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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