Perspectives on Biodiversity Valuing Its Role in an Everchanging World (1999) / Chapter Skim
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3: The Values of Biodiversity
3: The Values of Biodiversity
Pages 43-71
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From page 43... ...
For example, genetic diversity provides the basis of continuing adaptation to changing conditions, and continued crop productivity rests on the diversity in crop species and on the variety of soil invertebrates and microorganisms that maintain soil fertility. Similarly, a change in the composition and abundance of the species that make up an ecosystem can alter the services that can be obtained from the system.
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From page 44... ...
concluded that "no one yet knows how to engineer systems that provide humans with the life-supporting services that natural ecosystems produce for free." Biodiversity in Domesticated Systems Humans rely on a relatively small fraction of species diversity for food. Only about 150 species of plants have entered world commerce, and 103 species ~ This measure and measures that follow in the chapter are very general indications of monetary values associated with various aspects of biodiversity.
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From page 45... ...
Different landraces can contain genes that confer resistance to specific diseases or pests, make crops more responsive to inputs such as water or fertilizers, or confer hardiness enabling the crop to be grown in more extreme weather or soil conditions. Much of the genetic diversity available for crop breeding is now stored in a network of national and international genebanks administered by the UN Food and Agriculture Organization, the Consultative Group on International Agricultural Research, and various national agricultural research programs, such as the US Department of Agriculture's National Seed Storage Laboratory in Fort Collins, Colorado.
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From page 46... ...
Not only are specific genes valuable in modern agricultural systems, but the maintenance of genetic diversity is also valuable in traditional agricultural systems. The greater the genetic uniformity of a crop, the greater the risk of catastrophic losses to disease or unusual weather.
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From page 47... ...
Of the $55 billion in tourism revenues accruing to developing countries in 1988, an estimated 4-22% was due to "nature tourism" (Lindberg 1991~. More than half of the visitors in Costa Rica, for example, state that the national parks are their "principal reason" for traveling to the country (see the case study on Costa Rica in chapter 2~.
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From page 48... ...
Reduced genetic diversity increases the probability of species extinction or of substantial reductions in the population of a species due to changing environmental conditions (such as, a change in climate or the introduction of a new disease)
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From page 49... ...
Natural products were once the only source of pharmaceuticals, but by the 1960s synthetic chemistry had advanced to the point where the pharmaceutical industry's interest in natural products for drug development had declined greatly and it declined further with the introduction of "rational drug design". Several technological advances led to a resurgence of interest in research in natural products in the 1980s.
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From page 50... ...
Moreover, there would be a 97.5% chance that no product at all would be produced. The likelihood that any particular plant or animal will yield a new drug is extremely small, but endangered species in the United States have yielded new drugs.
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Nonetheless, the available data indicate that a higher level of species diversity in an ecosystem tends to increase the likelihood that particular ecosystem services will be maintained in the face of changing ecological or climatic conditions (below, "Species Diversity and Ecosystem Services"~. Both wild and human-modified ecosystems provide humankind with a variety of services that we often take for granted (see box 3-1~.
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From page 52... ...
Historically, ecosystem services were not generally scarce and management decisions were rarely based on their low marginal value. That is decreasingly true, particularly with regard to drinking-water quality, flood control, pollination, soil fertility, and carbon sequestration.
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From page 53... ...
The value of various ecosystem services can also be seen in the costs that must be incurred to replace them. For example, natural soil ecosystems help to maintain high crop productivity, and the productivity that is lost if soil is degraded through erosion or through changes in species composition can sometimes be restored through the introduction of relatively expensive fertilizers or irrigation.
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From page 54... ...
The human population of Southern Florida is now 4.5 million and growing at a rate of almost 1 million per decade, mostly concentrated along the lower eastern coast. The Everglades has been compartmentalized for a variety of land uses: agriculture in the north, where the largest accumulations of organic soils once existed; water conservation areas in the central portions; and the Everglades National Park in the south.
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From page 55... ...
At issue were maintenance of the integrity of the watershed and water quality, preservation of biodiversity in a region of great interest, conservation of endangered species as required by law, and the sustainability of natural resources in a setting of rapid economic and population growth. Two current examples illustrate the complexity of the process.
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From page 56... ...
It involves using portions of the EAA for dynamic water storage while it remains entirely or partly under private ownership; the EAA consists of 280,000 hectares, used primarily for sugar production, with total annual economic activity of about $1.2 billion (Bottcher and Izuno 1994~. A National Audubon Society report on the endangered species in the Everglades made a similar recommendation (National Audubon Society 1992~.
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From page 57... ...
But addition or removal of particular species could profoundly alter one or more services. Moreover, the presence of a diversity of species and the genetic diversity in those species will aid in the persistence of a particular service in the face of changing ecological and climatic conditions.
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From page 58... ...
Box 3-2 presents some changes in species or populations of particular species that have had substantial effects on ecosystem services. A particular species might compensate functionally for another that is removed from an ecosystem, but a simplified ecosystem is less likely to maintain a particular ecosystem service than one with a greater diversity of species playing similar functional roles.
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From page 59... ...
Some species might be most effective under current conditions; while others might become more important unless conditions change. For example, in an 11-year field experiment based on 207 grassland plots, increased plant species diversity resulted in greater stability in the community and ecosystem process in experimental plots, especially in the face of a severe drought (Tilman 1996; Tilman and Downing 1994~.
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From page 60... ...
By cultivating a connoisseur's perspective, we might develop a better understanding of the aesthetic value of biodiversity just as art critics and scholars help us to appreciate art. Information Biodiversity holds the potential for applied knowledge through the discovery of how different species have adapted to their varied environments (Wilson 1992~.
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From page 61... ...
Many of our insights about ourselves could only have come through the study of other species. For example, our knowledge of our development and reproduction rests on the study of many diverse species beyond the common laboratory species, such as bacteria, nematodes, rats, mice, and monkeys.
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It is impossible to predict how new knowledge will be used. Knowledge about various forms of life has, as seen in the above examples, had direct effects on improving human health and has led to revolutions in science, such as our understanding of molecular genetics.
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From page 63... ...
The experience of biodiversity provides such opportunities. The examples cited above suggest that diverse environments contribute to a self-knowledge that, although it can take a multitude of forms and is difficult to catalog, is nonetheless irreducibly valuable in its own right.
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From page 64... ...
The effort that we make to protect the habitats of native species entrenches a relationship between people and places. One sees one's own activities and those of one's community as rooted in a particular place; one's experiences, in other words, depend on where one is (Gallagher 1993; Light and Smith 1998~.
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From page 65... ...
The reintroduction and protection of native species, in contrast, follows Virgil's counsel: it is well to be informed about the winds, About the variations of the sky, The native traits and habits of the place, What each locale permits and what denies. Much of what many people deplore about the human subversion of natureand fear about the destruction of the environment has to do with the loss of places that they keep in shared memory and cherish with collective loyalty.
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From page 66... ...
Boulder now has the highest per capita acreage of municipally owned natural area of cities in the United States. The purposes of open space, as codified in a charter amendment approved by voters in 1986, are preserving and restoring natural areas and their biota, preserving land for passive recreational use, retaining traditional agricultural land uses, limiting urban sprawl, and preserving aesthetic values (City of Boulder Open Space Department 1995~.
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The case study examples of the Everglades and Boulder illustrate why a broadened understanding is necessary for management considerations. In the next chapter, we see that information on the many philosophical and systematic approaches to valuing biodiversity can favor particular outcomes in management decisions.
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From page 68... ...
Central and Southern Florida Project. Issue No 3 (December)
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From page 69... ...
In press. Ecosystem management to achieve ecological sustainability: The case of South Florida.
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From page 70... ...
Nature 368:734-7. National Audubon Society.
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From page 71... ...
New York NY: Basic Books. WRI [World Resources Institute]
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