Chapter OneThe Many Roads to Conservation
It is customary to start a book about conservation with a doom-laden outline of the impending biological and ecological crises that face the planet. In fact, most readers will have more than a passing awareness of the gravity of the current situation. A few images that depict the skeletal white hand of logging roads etched into an Amazonian satellite view, the scarred red earth of Madagascar blowing in the dust, or an immense lump of fallen rhino with the horn hacked away are enough to focus attention on biodiversity loss. At one level, the problem posed by the erosion of biodiversity is simple-it is happening and it needs to be slowed, better, stopped. But once you start examining proposed conservation strategies, or more specifically exploring the disciplines where such strategies are being crafted, only more questions arise. What is biodiversity? Why does it need conserving? What are the goals of biodiversity conservation? Who is involved in the practice of conservation, and what are their objectives? Such questions must be faced directly, since they frame any so-called solutions to the biodiversity crisis. Inevitably people will give wildly divergent answers to these kinds of questions, depending on when and where they live, their social, economic, and political circumstances, their personal experiences, and (at least among academics) their intellectual training or disciplinary affiliation. Yet answers to these questions take us a long way toward understanding changes in conservation thinking through time and help unravel the unique problems associated with the contemporary challenges discussed in this book.
In this chapter we look at some of these questions. Philosophers, artists, naturalists, ecologists, and activists have all written on these matters, and we cannot claim to offer anything other than a coarse overview of their positions. We start out with a summary of the principal threats to biodiversity (1.2) and an intellectual map of the reasons biodiversity should be saved (1.3 and 1.4). The core of the chapter lies in an examination of the historical evolution of conservation thinking. By focusing on this story in the United States, we demonstrate how tightly interwoven changing social and environmental philosophies are with conservation practice, in particular, protectionism (1.5), management (1.6), and multiple use (1.7). We also draw on a wider range of related issues from other parts of the world in the boxes. With this background we conclude by showing how, at the dawn of the modern conservation era, purely utilitarian objectives had largely succumbed to the highly preservationist goal of comprehensive biodiversity protection. We also point to the importance of distinguishing conservation goals and means, and to the fact that conservation is always about choices based on ethical values (1.8).
1.2 Principal Threats to Biodiversity
Biodiversity refers broadly to the full set of species, genetic variation within species, the variety of ecosystems that contain the species, and the natural abundance in which these items occur (OTA, 1987); in other words, it is an umbrella term for all of nature's variety (McNeely, 1990). Leaving historical (chapter 2), ecological (chapter 3), political (chapter 7), and global (chapter 9) aspects of the concept of biodiversity for later consideration, we consider here its major threats.
It barely needs repeating, the world is a very different place from what it was 10,000 years ago, and even 100 years ago. The changes of the last century radically restructured humankind's economic activities, political relations, and social and demographic profile. One prominent feature of this change is the accelerating scale of human impact on the Earth's natural biophysical systems-climate, stratospheric ozone, terrestrial and marine ecosystems, and the great cycles of water, nitrogen, and sulfur, all of which sustain the conditions on which life depends (McMichael et al., 1999; Vitousek et al., 1997). Clearly, the world our children inherit will be far more crowded, more polluted, and less habitable than the one we occupy today (Meffe and Carroll, 1997).
Closely associated with these broad changes in the global environment is the erosion of biodiversity, in particular, the loss of species, populations, and their habitats. The intricate relationships between levels of biodiversity, productivity, ecological complexity, stability, and environmental health are not well understood (May, 1999), but a pop rivet analogy nicely captures many biologists' thinking about loss of this diversity, given all the uncertainties. How many rivets can a financially strapped airline operator remove from its aircraft without impairing safety in flight? As with the removal of species and habitats from our planet, no one really wants to do the critical test. In the absence of precise details on the tolerance of human welfare to the current wave of extinctions, there is nevertheless increasing recognition that biological diversity is a key environmental asset under threat. In part, this is because of the evidence that certain ecosystems, such as speciose forests and highly productive marshes, play essential roles in maintaining a healthy, functioning ecosystem, and in part because many people hold strong ethical beliefs that nature deserves respect, often for purely inspects trinsic reasons (see below). The erosion of biodiversity is reflected in extinction rates (Wilson, 1988). Though extinction is a natural evolutionary process, its rate over the last century ranged from 100 to 10,000 species per year (Pimm et al., 1995) compared to a one to ten species a year background rate, based on paleontologists' estimates. This has been called variously an "extinction crisis" (Soule, 1986) or an "extinction spasm" (Myers, 1987).
Mass extinctions have occurred before; there have been five, at the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous, spanning geologic time from 430 mya to 65 mya, when the dinosaurs met their end. These were all "natural events," and usually occurred over many hundreds or thousands of years. The present extinction spasm is considered to be unnatural (and unique) insofar as it is driven by a single species-humans. In contrast to other extinctions, which were probably driven by large-scale climatic changes that affected many or all species, our current crisis affects species in a more systematic way: large-bodied, economically significant, and habitat-sensitive species are being extirpated and replaced by smaller, generalist species that thrive in human-dominated places. The current situation is notable also for its extreme rapidity, and the fact that between one-third and two-thirds of all species on earth will disappear within the foreseeable future if the present trend continues unchecked (Pimm et al., 1995; Wilson, 1992). With species loss goes the eradication of locally adapted populations, habitats, and the evolutionary and ecological processes whereby these species coevolve and coexist.
Biodiversity is strongly patterned. Its greatest storehouse lies in areas that are warm and humid, especially tropical rainforests which, although they occupy less than an estimated 7 percent of the Earth's surface, are thought to contain at least 50 percent of the world's species (Wilson, 1988). Although species diversity is also associated with altitude, area size, successional stage, and other factors (considered in chapter 3), the latitudinal effect is strong. For example, of the twenty-five biodiversity hotspots, areas highlighted for the prioritization of global conservation efforts, sixteen lie in the tropics (Figure 1.1). This means that remaining biodiversity is found largely in developing countries, where conservation resources are scarcest, where habitat conversion is most rapid (Dobson et al., 1997), and where the threat to biodiversity is greatest. Notably, too, species richness is concentrated in areas of high human density, both at a global scale (Cincotta et al., 2000; see chapter 8) and within continents (at least as shown for Africa; Balmford et al., 2001), even when latitudinal differences are controlled. Given that the population projections for 2050 are highest for many of the world's poorest countries (Bongaarts and Bulatao, 2000), the challenge for conservationists is all the more acute. None of this means that blame is to be laid at the door of developing rather than developed nations. In fact, almost the converse: a good proportion of the extraction of natural resources supports businesses owned by Westerners or Westernized national elites (chapter 7). With so much of the Western and developed world already environmentally degraded, a guilty focus necessarily settles on areas of remaining diversity (chapter 9).
The direct and indirect causes of biodiversity declines are extremely complex, and rarely if ever exclusively local. Virtually everything we do affects species diversity. Sometimes these outcomes are positive: for instance, there are activities that potentially enhance species diversity and habitat protection, such as programs that establish wildlife reserves, mount species survival programs, or manage botanical and zoological parks, as well as many traditional natural resource management practices that may be quite effective (chapters 4 and 5). However, the majority of human activities, particularly in recent years, are detrimental to diversity. The broad anthropogenic processes of deforestation, desertification, pollution, agricultural expansion, and urban sprawl drive species extinction, spearheaded by an "evil quartet" of mechanisms habitat loss, overexploitation, introduced species, and pollution; e.g., Purvis et al., 2000). Furthermore, though the 6.5 billion and growing) world population is a key ingredient of biodiversity loss, equally important factors are where these people live and the inequities in what they consume. In the developing world many people are forced to live in fragile areas not well suited to human habitation, whereas in industrial countries (and among elites in the developing world) the wealthy consume a disproportionate share of nature's products, whether this be water, wood, or wilderness experience (Figure 1.2). In fact, standing back from the local sites of biodiversity erosion, it becomes clear that the most distal causes of biodiversity decline are probably the most important: the steady narrowing of traded products from agriculture, forestry, and fisheries, promoting monoculture and genetic loss; deficiencies in knowledge and its applications; and legal and institutional systems that promote unsustainable exploitation (WRI, 1992). These global processes are examined further in chapters 7 and 9.
1.3 Why Conserve Nature? Instrumental Values
Why is there a need to conserve biodiversity? The reasons are neither obvious nor widely agreed upon (Norton, 2000). Environmental philosophers identify two very different sets of arguments, based on the utilitarian (or instrumental) versus the intrinsic (or inherent) value of nature. The utilitarian value of nature refers to the product or function that nature can provide, whereas intrinsic value inheres in the natural object or system itself, irrespective of whether it has any use. Arguments for conserving biodiversity that are based on the utilitarian value are often labeled anthropocentric (human-centered), whereas the arguments predicated on intrinsic value are often called biocentric (or ecocentric) since the value exists independent of its use to human beings. Though philosophers are somewhat troubled by the tautology entailed in the anthropocentric position, pointing out that enjoyment or use of an object is ultimately based on some inherent value (Sagoff, 1988), the intrinsic/utilitarian distinction remains enormously helpful for thinking about the arguments for conserving bioversity.
The utilitarian value of biodiversity may be divided into four basic categories: goods, services, information, and spiritualism (Table 1.1). As regards nature's goods, people need food fuel, fiber, and medicine, items they can obtain both through collection in the wild and through cultivation. The utility of the vast majority of species is still unknown, with respect to both undiscovered medicinal properties (see chapter 8) and genetic diversity. As regards the latter, although more than 20,000 edible plants are known, and perhaps 3,000 have been used by humankind throughout history, the world's food supply is dominated by many fewer (Prescott-Allen and Prescott-Allen, 1990) and according to some analyses a mere handful of crops (Vietmeyer, 1986). The genetic diversity that lies in the wild ancestors of wheat, oats, and barley that still occur in the arid hills of Galilee could, for example, save conventional food resources from incurable disease or uncontrollable pests. Nature's services (often referred to as ecosystem services) are a product of such a vast, invisible natural economy that they were, until quite recently, overlooked! For example, green plants replenish oxygen and remove carbon dioxide from the atmosphere, fungal and microbial organisms decompose dead organic material and recycle plant nutrients, and rhizobial bacteria turn atmospheric nitrogen into usable nitrate fertilizer for plants. Fear about the stress to which ecosystems can safely be subjected when several of their component species go extinct was popularized by Commoner (1971), and this question has become central to the field of conservation biology (see chapter 3). The information value of nature lies not only in the estimated 5 to 15 million species that exist, most of which are still unknown to science (May, 1999), but in the evolutionary and ecological processes that allow these species to coexist. As Ehrenfeld (1976) argues, the study of intact functioning ecosystems provides blueprints for habitat reconstruction, design principles for new ecosystems, environmental baselines for monitoring threatened systems, and a wonderful teaching laboratory for the ecologists of the future. Finally, as regards psycho-spiritual value, nature offers rich meaning to human existence, for some an emotional touchstone, for others a sense of spiritual or intellectual purpose. This derives not only from the exquisite excitement of scientific discovery, but also from the beauty and more diffuse sense of awe and mystery that can be found in nature. This complex value E. O. Wilson (1984) calls "biophilia," invoking the strong bonds humans can feel with nature. A clear example of how conservation can be rationalized on utilitarian grounds, combining nature's goods, services, information, and spiritual value, is found in the Biodiversity Support Program's (BSP) emphasis on the links between health and conservation (Box 1.1).