Chapter Three: Priority-Setting In Practice
This chapter reviews a variety of priority-setting methods representative, but not inclusive, of the many approaches developed or used around the world in recent years. Taken together, these examples illustrate various ways in which biodiversity priorities can be defined at the species and ecosystem levels and at different geographic scales (eg global, regional, national, or local). These methods reflect a tremendous amount of analysis, innovation, and dedication to the conservation of biodiversity on the part of their creators.
None of the examples discussed in this chapter should be applied wholesale to a new setting. Each reflects a unique set of objectives, underlying values or assumptions, and circumstances. However, readers should be able to identify specific approaches, or elements from several approaches, that can be adapted to form the basis for new priority-setting efforts. Rather than being viewed as a set of competing methodologies, the examples presented here should be seen as a rich resource for informing future priority-setting efforts.
The examples are grouped according to the geographic levels for which they were developed - global, regional, and national or local. This is an arbitrary division in some ways. Most of the examples could (with modification) be used at any geographic scale. Any alternative grouping (by method of analysis, for example) would risk being arbitrary as well. Therefore, the reader is urged to consider the concepts behind different methods rather than focus on the geographic scale categories used here to organize the chapter.
The examples profiled in this chapter are categorized in Table 3.1 by the criteria (rarity, distinctiveness, threat, utility, etc.) and approach categories (genetically-based, species-based, ecosystem-based, and integrative) that best characterizes each methodology.
Setting Global And Regional Priorities
The most visible efforts to establish conservation priorities in recent years have centered on identifying those parts of the world with the greatest biodiversity. These efforts are driven by several considerations. First, biodiversity is unevenly distributed around the world, with some nations having greater diversity than others, just as within a nation some ecosystems have more species than others. Second, biological resources found in one area can have regional or global significance in addition to local and national value, especially in terms of genetic resources for agriculture and pharmaceuticals. Third, most of the world's species are found in the tropics, where countries with limited conservation resources (e.g., funding, training, etc.) face enormous pressures on their biological resources. Fourth, conserving biodiversity will require international investments to share the cost of maintaining biological resources, the benefits of which often flow beyond national borders.
Table 3.1 Typology Of Priority-Setting Approaches
Priority-Setting
ApproachesCriteria for Assigning Conservation Value Type of Analysis Biological Social & Institutional Genetically-
BasedSpecies-
BasedEcosystem-
BasedIntegrated Richness Distict-
ivenessRarity Represent-
ativenessThreat Function Utility Feasi-
bilityOther
Global Priorities
Biodiversity Hotspot Areas *
*
*
Megadiversity Countries *
*
Major Wilderness Areas
* *
*
*
Centers of Plant Diversity *
*
*
Endemic Bird Areas *
*
*
*
Large Marine Ecosystems *
* * *
*
Regional Priorities
IUCN Regional
Protected Areas Reviews*
* *
*
CPTI for Indo-Pacific
& Latin America Regions
* *
*
*
Priority-Setting Workshopsin South America *
*
*
*
IUCN Species Survival Action Plans
* * * *
* *
BSP Priority-Setting Framework *
* *
* *
* National & Local Priorities
Natural Hertitage Programs * * * * * *
* *
Papua New Guinea *
* *
*
* *
Conservation Needs
Assessment / Gap Analysis in the U.S.*
*
*
*
Iterative Approaches to Reserve Selection in Australia
*
*
*
Identification of Useful Plants for Conservation and Development
* *
* *
*
*
Priorities for Conserving Genetic Diversity in Forest Trees * * * * * *
*
Ecologically Sensitive Areas *
*
* * * * *
* * * Biodiversity, in other words, is often considered to be a global good with international value that exceeds the value that accrues to an individual country. Because its conservation is very likely to cost more than what an individual country can afford, particularly in the tropics, and because the benefits of conservation accrue to those outside individual countries, other countries will have to help. In recent years, donor agencies have been investing more resources in biodiversity conservation (Abramovitz, 1991; Abramovitz, 1994), and they have also been seeking ways to identify international biodiversity conservation priorities to guide their investments (e.g., Dinerstein and Wikramanayake, 1993; Braatz et al., 1992; WCMC, 1994; Dinerstein et al., 1995; BSP et al., 1995). Now that the Convention on Biological Diversity has entered into force, this will intensify.1
Although disagreements over the balance between biodiversity as a global good and as a national sovereign resource have often divided the international community, the Convention obligates member countries to protect biological resources for national and international benefits. Among other things, the Convention also starts a process to establish financial mechanisms that can assist members in carrying out their obligations. The resources available to do so are limited, meaning that donors (mostly countries in Europe and North America, and Japan) and international agencies with Convention-related responsibilities (e.g., the Global Environment Facility) will have to devise mechanisms for directing resources.
For the most part, international approaches to setting geographic priorities have assumed that using the number of species (and sometimes endemism rates) is the most effective way to broadly distinguish conservation priorities between countries or regions. Most approaches focus on species richness for the best understood taxonomic groups because they are the most easily measured (albeit incomplete in most areas) indicators of biodiversity.
Some international approaches add additional criteria to further narrow priorities. For example, the "hotspots" approach (Myers, 1988) examines various indicators (e.g., deforestation rates) to identify which of the areas richest in biodiversity are most imminently threatened by habitat loss and species extinctions (see Box 3.1).
International priorities have been set using different scales of analysis, which McNeely et al. (1990) have categorized as regional, national, and site. Regional analysis often distinguishes between major biogeographic units, irrespective of political boundaries. For example, the eastern Himalayas, encompassing parts of Nepal, India, Bhutan, Tibet, and China, are considered a priority region under one method (Myers, 1988). National analysis, on the other hand, distinguishes among individual countries, as in the "megadiversity" countries approach (Mirrermeier, 1988), which identifies Indonesia, Colombia, and Zaire and several other countries as international conservation priorities because they have high species richness and endemism levels with their borders. Still, priorities determined under either of these levels of analysis are relatively broad, and will require further elaboration at the national, regional, or local level. Finally, the site approach to setting international priorities focuses on individual habitats or sites known to be important to certain taxonomic groups, such as birds (Bibby et al., 1992) or plants (WWF and IUCN, 1994). Site approaches are likely to be much more specific than regional and national approaches to setting international priorities.
Box 3.1 Data Evaluated In Myers "Hotspot" Analysis
- Extent of original (pre-agricultural) habitat
- Extent of present habitat Geographic patterns of plant species diversity
- Geographic patterns of plant species endemism
- Estimated "total of plant species eliminated or on verge of extinction"
- Diversity in other taxonomic groups, if known
- Human population growth rates
- Deforestation rates
Source: Myers (1988)
Approaches For Setting Global Priorities
Six efforts to set priorities at the global scale are presented below. These examples, in principle, have no geographic limits to their analysis, although the first five ("biodiversity hotspot areas," "megadiversity countries," "major wilderness areas," "endemic bird areas, and "centers of plant diversity") focus on terrestrial areas. The sixth is an example of priority-setting for coastal and marine areas.
Biodiversity "Hotspot" Areas
In 1988, British ecologist Norman Myers published an article in which he identified international conservation priorities on the basis of species richness and endemism, combined with an assessment of threats to natural habitats. The results of his "hotspots" analysis have since become perhaps the most commonly cited list of conservation priorities of any kind. References to the Myers (1988) "hotspots" are frequently encountered in the conservation literature and occasionally in the media, usually in the context of international or tropical biodiversity conservation efforts. The Myers analysis has also had considerable influence on the funding decisions of a number of public and private donors that support international conservation efforts.
The methodology first used by Myers is relatively simple. He made several important initial assumptions: that species richness and endemism are the best indicators of biodiversity values, that floristic diversity patterns are broadly representative of other taxonomic groups, and that humid tropical forests are the most important ecosystems for biodiversity conservation and among the most threatened. The objective was then defined as identifying tropical forest areas that have exceptional concentrations of plant species numbers (i.e., species richness) and high levels of endemism and that also face exceptional degrees of threat from human activities. Myers termed these areas biodiversity "hotspots."
Table 3.2 Location Of Biodiversity "Hotspots" And Number Of Endemic Species
Region Plants1 Mammals2 Reptiles2 Swallowtail
Butterflies2Cape Regionb
(South Africa)6,000 15 43 0 Upland Western
Amazoniaa5,000 - - - Atalntic Coastal
Brazila5,000 40 92 7 Madagascara 4,900 86 234 11 Philippinesa 3,700 98 120 23 Northern Borneoa
(Malaysia, Indonesia)3,500 42 69 4 Eastern Himalayasa
(Nepal, Bhutan, India)3,500 - 20 - S.W. Australiab 2,830 10 25 0 Western Ecuadora 2,500 9 - 2 Colombian Chacoa 2,500 8 137 0 Peninsular Malaysiaa 2,400 4 25 0 California Floristicb
Province (USA)2,140 15 15 0 Western Ghats (India)b 1,600 7 91 5 Central Chileb 1,450 - - - New Caledoniaa 1,400 2 21 2 Eastern Arc Mountainsb
(Tanzania)535 20 - 3 S.W. Sri Lankab 500 4 - 2 S.W. Côte d'Ivoireb 200 3 - 0 Total 49,955 375 892 59 Sources: a - Myers (1988); b - Myers (1990); 1 - plants from Myers (1988; 1990); 2 - other taxonomic groups from WCMC (1992). To identify the "hotspots," Myers collected data (Box 3.1) on such factors as the extent of primary forest habitats, the biogeography of plant diversity and distribution patterns in the humid tropics, rates of plant species endemism, and estimates of endangered plant species. By looking at human population growth rates in combination with deforestation rates, Myers assessed the degree of threat to those forest areas with high levels of species richness and endemism among higher plants2. Although the analysis is based on the distribution of plant species richness, Myers found that such areas are also relatively species-rich for some vertebrate and invertebrate animals. However, he does not present comparable data between sites for these taxa.
Although the 10 "hotspots" identified in the original Myers (1988) analysis include only 3.5 percent of the remaining primary humid tropical forest (and only 0.2 percent of the earth's land surface area), these areas are home to at least 27 percent of the higher plant species found in the tropics, and nearly 14 percent of all of the world's plants (see Table 3.2).
Myers recognizes the limitations facing conservation biologists who attempt to compile data from which to assess conservation priorities. At their best, some figures can be taken as fairly accurate (perhaps within 5 percent), but others are little more than "best guesses" of specialists who have worked in a specific area for many years. Nevertheless, Myers concludes that the overall approach, uneven as it is, is justified as an analytical exercise that seeks to delineate the conservation challenge facing the humid tropical forests.
The original "hotspots" analysis was limited to tropical forest regions and therefore neglected a number of extremely important temperate and non-forest areas. For example, in the semi-arid grasslands and mountains south of the Tropic of Capricorn in southern Africa (South Africa, Lesotho, Swaziland, Namibia, and Botswana), the high plant species diversity (23,200 species) is also exceptionally high in endemism (18,560 or 80 percent). This gives the area the world's greatest plant species richness (calculated as species/area ratio), or 1.7 times greater than Brazil (Davis et al., 1986). The region also has the highest concentration of threatened plant species (2,373) of any temperate region (McNeely et al., 1990). Recognizing this limitation, Myers (1990) expanded his earlier analysis to identify eight additional terrestrial "hotspots," four in the humid tropics and four in Mediterranean-type habitats (Table 3.2).
The Myers analysis is widely recognized as a timely advance in determining where conservation needs are greatest and where the potential benefits of conservation might be maximized. It has limitations, however. Among the problems are the limited distribution data for many of the world's plant species, limited knowledge of endangered status, and the difficulty of quantifying threats to habitat areas. The "hotspots" approach does not address the number of species per unit area, which would provide a more accurate reflection of the relative levels of biodiversity between areas. And while the "hotspots" are geographically limited, they are nor precise enough to allow conservationists, governments, or donor agencies to take action without a more detailed assessment of conservation priorities within the "hotspot" area. One response to this problem has been to develop techniques to rapidly assess biodiversity in areas where information on species and ecosystems is limited (Box 3.2).
In addition, it is not yet clear how indicative plant species distributions are for other taxonomic groups. For example, Daniels et al. (1991) show that centers of plant diversity in India are not necessarily centers of diversity for other taxonomic groups. In the United Kingdom, researchers empirically tested whether species-rich areas for different taxa coincide and whether species-rich areas contain substantial numbers of rare species (Prendergast et al., 1993). For Britain, at least, the findings indicate that "hotspots" for different taxa rarely coincide, and that most rare species do not occur in the most species-rich areas.
Megadiversity Countries
Another approach developed at the same time as the "hotspots" analysis has become widely cited in the context of international conservation priorities. Developed by Russell Mittermeier and others, the "megadiversity countries" concept is based on three premises (Mittermeier, 1988; Mittermeier and Werner, 1990):
- Although international conservation priorities should ideally be based on basic scientific information on biodiversity and endangered ecosystems, it is governments of sovereign nations policies and programs;
- Biodiversity is not evenly distributed among the world's more than 170 countries; and
- A very small number of countries, lying wholly or partly within the tropics, contain a high percentage of the world's species (including species from marine, freshwater, and terrestrial habitats), and most of them require special international conservation attention.
Several kinds of biological information are integrated in the "megadiversity" concept, although species numbers and levels of endemism (at the species level and higher taxonomic levels) are the main determinants of whether a country is considered to be a "megadiversity" country. Based on initial analysis, a dozen countries were included in the first list of megadiversity countries: Brazil, Colombia, Ecuador, Peru, Mexico, Madagascar, Zaire, Australia, China, India, Indonesia, and Malaysia (see Table 3.3). Together, these countries contain as much as 60 to 70 percent (and perhaps more) of the world's species.
The list of megadiversity countries was prepared from published and unpublished species lists, as well as in-country literature and field research conducted by Conservation International. Although Table 3.3 presents a straight-forward tally of species diversity, the megadiversity analysis also considers endemism levels (Mittermeier, 1988; Mittermeier and Werner, 1990; McNeely et al., 1990). For example, a number of countries would rank ahead of Madagascar solely on the basis of species diversity (e.g., the United States, Thailand, Venezuela). However, the extraordinary endemism among all taxonomic groups in Madagascar, despite lower overall species richness, led to its listing as a "megadiversity" country. On the other hand, the United States is left off the list, despite its high species diversity, presumably because endemism rates are generally low (i.e., many species in the United States are also found in Mexico and Canada).
The main advantage of the megadiversity approach is that it provides a straightforward, relatively quantitative analysis that results in conservation priorities defined by political boundaries (this is also a disadvantage; see below). This is appealing to donors, since they negotiate with individual governments and because their funding and development priorities are usually defined by political geography, not biogeography. In addition, most of the information needed for setting priorities is organized by countries, and not by biogeographic regions. Finally, most conservation programs and policies are developed by national governments - conservation agencies defined on the basis of biogeographic boundaries may be an ecologist's favorite daydream but they simply do not exist.
The megadiversity approach has a number of limitations, however. Species richness and endemism are only the simplest indicators of biodiversity. They do not convey other ecological dimensions of biodiversity, such as human dependency or serious threat. For example, centers of diversity for economically important wild plant species will not always coincide with the megadiversity countries. Like the Myers (1988) "hotspots" approach, conservation priorities determined by the megadiversity approach are heavily biased toward humid tropical forest areas. If conservation resources were directed primarily to megadiversity countries, many biomes and the vast majority of ecosystem types which are found elsewhere in the world would be neglected. Because tropical forest ecosystems are so disproportionately species rich, and the megadiversity and hotspots analysis so reliant on species richness, they put priority setters in the awkward position of favoring certain types of ecosystems and their inhabitants over others - even if that was not the intent.
Finally, the country-level analysis obscures the actual distribution of biodiversity. For example, if the island of New Guinea were a single country, there is little doubt - with its high endemism rates and limited species ranges - that it would be a megadiversity country. But the island is shared by two countries, Indonesia (the province of Irian Jaya) and Papua New Guinea. Indonesia is a megadiversity country but Papua New Guinea is not. There is, however, no guarantee that conservation resources allocated to Indonesia would go to the province of Irian Jaya. "When ranked on a species/area basis, six of the top dozen countries (Costa Rica, Panama, South Africa, Venezuela, Guatemala, and Haiti) are not on the megadiversity list (see WRI 1994). In other words, megadiversity countries are rankings of countries determined largely by their area (large) and location (tropical); their species richness and endemism5 simply reflect these two important biogeographical factors.
Box 3.2 Rapid Ecological Inventory And Assessment In Belize
A lack of information is a major constraint to better biodiversity conservation planning and management, particularly in the tropics. One strategy pursued in a growing number of areas around the world is to quickly augment limited information on biodiversity with the use of rapid ecological assessments and inventories. Experienced field researchers using simple but standardized survey techniques are common elements of rapid biodiversity assessment programs.
Two of the more prominent examples of these assessment programs have been used recently in the Maya Mountains of Belize, a country with the largest contiguous area of tropical forest remaining in Central America. The Rapid Assessment Program (RAP) developed by Conservation International uses experienced international and local biologists to survey - within a matter of weeks - the biota of an area thought to be of high conservation value. The Conservation International RAP team, including biologists from Belizan organizations, visited the Columbia Forest River Preserve to assess the conservation importance of this little-known area in the southeastern Maya Mountains on the border with Guatemala. Their findings suggest the reserve contains the most species-rich plant and animal communities in Belize (Parker et al., 1993).
The Rapid Ecological Assessment (REA) program developed by The Nature Conservancy is designed to quickly identify management actions needed in areas already known to be of significant conservation value. Joined by the Belize Audubon Society, and the Program for Belize, The Nature Conservancy organized a Rapid Ecological Assessment (REA) of the Bladen Nature Reserve, which happens to be adjacent to the Columbia River Forest Reserve. Interdisciplinary teams of Belizan and international scientists (including social scientists) surveyed species distributions, plant communities, and human uses of the area to identify the most important management actions for the reserve (Iremonger and Sayre, 1994).
Strictly speaking, neither the RAP nor the REA approaches are priority-setting methods in themselves. Neither approach ranks sites on a comparative basis and then selects among them. Their proponents, however, clearly see them as complementary tools to priority-setting processes.3
Critics of programs such as RAP and REA fear that such approaches undermine support for long-term scientific field research (Abate, 1992). The results of such surveys have not been published in peer-reviewed journals, they charge, because the methods would not stand up to scientific scrutiny. Proponents of rapid biodiversity assessments respond that scientific rigor is not their goal. In a recent article on the controversy, Ted Parker4 - prominent participant in Cl's RAP missions - concluded, "Ten or fifteen years from now our scientific contributions won't be important, but there may be some places that still exist because of what we've done." (Abate, 1992). In the meantime, RAPs, REAs, and similar approaches have proliferated in many parts of the world.
Major Wilderness Areas
A considerably different approach is embodied in the identification of major wilderness areas (McCloskey and Spalding, 1989; CI, 1990). Whereas the "hotspots" analysis considers the urgency of human threats to a limited subset of natural habitats, in combination with species diversity, the wilderness approach emphasizes the identification of large relatively undisturbed natural areas with low human population densities and does not explicitly evaluate species diversity or endemism. It can be assumed that wilderness areas in the humid tropical forest biome are relatively rich in biodiversity, although some areas will be more important than others, and some areas within a particular wilderness area will be more diverse than others. Globally, relatively undisturbed habitats cover approximately one third of the earth's land surface (McCloskey and Spalding, 1989) - much of it composed of desert, boreal, and arctic/Antarctic ecosystems (see Tables 3.4 and 3.5). As relatively undisturbed habitats shrink in the temperate, tropical, and even boreal zones, these wilderness areas will become increasingly important for the conservation of biodiversity.
The objective of the McCloskey and Spalding (1989) inventory was to identify only large blocks of wilderness with over 400,000 hectares. They defined wilderness as it appears in the U.S. Wilderness Act, i.e., land that "generally appears to have been affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable." As McCloskey and Spalding (1989) point out, this does not mean that such areas are pristine or absolutely untouched. It does mean that wilderness is land without settlements or roads and is not regularly cultivated or heavily and continuously grazed. Most of this land has been lightly used and occupied by indigenous peoples at various times, and seasonal pastoralism, particularly in arid and upland areas, will have been common.
Table 3.3 Species Diversity in Selected Countries
Mammals Birds Reptiles Angiosperms Swallowtail
ButterfliesMegadiversity Countries1 Brazil 428 1,622 467 55,000 74 Colombia 359 1,721 383 45,000 59 China 394 1,195 265 27,000 99-104 Mexico 449 1,010 717 25,000 52 Australia 255 - 686 23,000 - Indonesia 515 1,519 >600 20,000 121 Peru 361 1,701 297 20,000 58-59 Ecuador 280 1,447 358 15,000 64 Malaysia 293 1,200 171 15,000 54-56 India 350 1,200 182 14,500 77 Zaire 409 1,086 280 11,000 48 Madagascar - 250 269 10,000 - Other Countries for Comparison2 United States 466 1,090 368 20,000 30-31 France 113 342 36 4,500 - Costa Rica 203 218 218 8,000 - Sources: 1 - Adapted from McNeely et al. (1990); 2 - WRI (1992). From a global biodiversity perspective, wilderness areas in the tropics, particularly the humid tropics, are most important. Large wilderness areas in most of the temperate world have disappeared, and major wilderness areas in the tropics are becoming increasingly rare. There are, however, a few major tropical wilderness areas where very large tracts of primary forest are likely to persist well into the next century. Although more threatened habitats, such as those identified by Myers (1988; 1991), will require more urgent attention and higher levels of funding for conservation, major wilderness areas should not be overlooked in the assessment of conservation priorities. These areas will be increasingly important, as McNeely et al. (1990) indicate, because:
- They will be the last areas where major evolutionary processes can continue to take place with only limited impacts by humans (although the influence of climate change and pollution are becoming increasingly pervasive);
- They can serve as "controls" against which the effects of human activities in managed ecosystems can be measured;
- They are major storehouses of biodiversity, where large numbers of individuals of many species will continue to exist;
- They play a key role in maintaining local, regional, and, in some cases because of their large size, global climate patterns;
- They will be the last areas where aboriginal peoples can choose to continue to live their traditional lifestyles; and
- They will represent increasingly rare aesthetic, spiritual, and scientific values in an increasingly crowded, urbanized world.
Using Jet Navigation Charts and Operational Navigation Charts published by the U.S. Defense Mapping Agency at a scale of 1:2,000,000 and 1:1,000,000, McCloskey and Spalding (1989) eliminated all areas showing roads, settlements, buildings, airports, railroads, pipelines, power lines, canals, causeways, aqueducts, major mines, dams and reservoirs, and oil wells. Although the maps did not show agricultural development or logging, these activities usually depend on proximity to roads and settlements. Most of the charts were last updated in the early-to mid-1980s, but in many areas more recent map sources were consulted for verification. McCloskey and Spalding (1989) concede that the inventory has weaknesses (e.g., varying levels of map detail on human artifacts on the landscape), but argue that in aggregate, the findings are reasonably accurate.
Table 3.4 Distribution Of Larger Wilderness Areas By Continent
Continent km2 Wilderness
% of Total# of Areas1 Antarctica 13,208,983 100 2 North America 9,077,418 37.5 85 Africa 8,232,382 27.5 434 Former Soviet Union 7,520,219 33.6 182 Asia2 3,775,858 13.6 144 South America 3,745,971 20.8 90 Australia 2,370,567 27.9 91 Europe2 138,553 2.8 11 Total 48,069,951 32.3 1,039 1 - Only contiguous areas of at least 4,000 km2 are included.
2 - Does not include former Soviet Republics.Sources: McCloskey and Spalding (1989).
The inventory produced an area of approximately 48 million square kilometers of wilderness in 1,039 separate areas in 77 countries, covering 32.3 percent of the earth's land surface area (see Table 3.5). Using the Udvardy biogeographical system,6 McCloskey and Spalding show that 41 percent of large wilderness areas are found in the high arctic or Antarctic, 20 percent in warm desert areas, 20 percent in temperate regions (mostly in the boreal or taiga province), 11 percent in the tropics, 4 percent in mixed mountain systems, 3 percent in cold desert regions, and a small fragment is found in island regions.
Table 3.5 Wilderness Distribution By Biome
Biome km2 % of Total # of Areas Tundra Communities 20,047,533 41.7 100 Warm Desert / Semi-Deserts 9,329,531 19.4 389 Temperate Needleleaf Forests 8,799,312 18.3 120 Tropical Humid Forests 3,006,855 6.3 77 Mixed Mountain Systems 1,973,391 4.1 76 Cold-Winter Deserts 1,478,494 3.1 51 Tropical Dry Forests 1,424,099 3.0 120 Tropical Grasslands / Savannas 735,331 1.5 33 Temperate Rainforests 450,215 0.9 15 Temperate Broadleaf Forests 290,646 0.6 20 Temperate Grasslands 272,016 0.6 24 Evergreen Sclerophyllous Forests 170,885 0.4 7 Mixed Island Systems 91,647 0.2 7 Total 48,069,951 100.0 1,039 Source: McCloskey and Spalding (1989). The McCloskey and Spalding (1989) wilderness inventory does not identify biodiversity conservation priorities per se. Conservation International (1990), a nongovernmental organization based in the United States, has modified the wilderness inventory approach to assess humid tropical forest conservation opportunities as part of its Rainforest Imperative program. The major tropical forest wilderness areas identified as conservation priorities include the island of New Guinea; the humid tropical forests of the Zaire Basin (Zaire, Congo Republic, and Gabon); and a major arc of forest wilderness from southern Guyana and Suriname, across southern Venezuela, the northern Brazilian Amazonia, and down through the western Amazonian lowlands of Brazil, Colombia, Ecuador, Peru, and Bolivia.
The advantages of identifying major wilderness areas as priority sites for biodiversity conservation include: lower management and maintenance requirements; large habitat areas for a wide range of species, especially large predators, encompassing most if not all species for the ecosystems within the wilderness; and relatively few of the social and economic pressures that afflict most smaller habitat "islands" surrounded by intensive land uses.
Perhaps the greatest disadvantage to this approach is that wilderness is viewed as a western concept with little value or desirability in many developing countries. In addition, wilderness does not lack owners. What appears as "wilderness" in a satellite image or to the casual outside observer is often someone's home. There are other disadvantages as well: a) there may be little information on how much biodiversity is actually included in the wilderness area, b) other areas with higher concentrations of biodiversity may be missed because they are not classified as wilderness," and c) attention focused primarily on large wilderness areas with few imminent threats may divert resources from areas facing more urgent problems.
Finally, the relatively "undisturbed" wilderness area, as defined by McCloskey and Spalding (1989), may be overrepresented for some biomes. For example, relatively low human population densities (and grazing animal densities) can have significant adverse impacts on grass-land ecosystems, especially in semi-arid regions. Transhument pastoralism in some grassland and other semi-arid regions represents a seasonal or prolonged period of human and livestock presence that will not be registered by identifying settlements and other infrastructure on jet navigation charts.
In any case, identifying wilderness areas should be viewed as a first step in defining more detailed priorities and should not be viewed as a comprehensive approach to setting biodiversity priorities. Nevertheless, knowing where wilderness areas are can help to focus biodiversity assessments in areas where conservation prospects are less complicated by human activities.
The three previous examples identify large areas (i.e., countries or regions) as global conservation priorities. The two following examples, centres of plant diversity and endemic bird areas, involve identifying individual sites or habitats critical to threatened or endemic species, or an unusual concentration of species. Site approaches identify priorities without specific reference to country or biogeographic boundaries. Priorities identified in this way have the advantage of being relatively precise in geographic terms. At the same time, they are often limited to a narrow subset of species or habitats. For example, an approach may identify well-defined habitats that are important to endemic birds, but such habitats may do little for the conservation of many other elements of biodiversity. However, sites of concentrated diversity or endemism for some groups of organisms may be indicative of biodiversity concentrations more generally. In any case, sites identified in this way may be used to add specificity to more general country (e.g., megadiversity) or regional (e.g., hotspots) priorities.
Centres Of Plant Diversity
Plants are vital constituents of any ecosystem and are usually the most visible indicators of habitat types and condition. Moreover, it is estimated that as many as 60,000 of the world's approximately 250,000 vascular plant species may become extinct before the middle of the next century (IUCN, 1987). These reasons, plus the fact that plants as a taxonomic group are generally well known, provide a good basis for using plants to identify conservation priorities.
In 1986, the IUCN and the World Wide Fund for Nature (WWF) initiated a project to identify major centres of plant species diversity (IUCN, 1987). The goal of the project was to identify places with unusual concentrations of plant diversity and endemism that, collectively, represent a majority of the world's plant species. The final list of sites for the "Centres of Plant Diversity" project is 234, most of them in the tropics (see Tables 3.6 and 3.7).
The project is intended to identify "first order" sites of global significance. The sites were chosen without reference to political boundaries. Some countries have numerous sites (e.g., Indonesia), while others (e.g., Egypt) have none. The ultimate goal is to confer some form of protected area status to all vulnerable sites - many of which already are included in protected areas and nevertheless remain vulnerable.
Working with botanists and other collaborators from around the world, the Centres of Plant Diversity Project identified three basic types of sites (WWF and IUCN, 1994):
- botanically rich sites that are well-defined geographically (e.g., Mt. Kinabalu in Sabah, Malaysia on the island of Borneo, or Darien National Park in Panama);
- less well-defined geographic regions with high species diversity and/or endemism (such as the High Atlas Mountains of Morocco or the Klamarh-Siskiyou Mountains of Oregon and California); and
- vegetation types and floristic provinces that are exceptionally rich in plant species (such as the Cape Floristic Province in South Africa, or the Atlantic Forests in southeastern Brazil).
Table 3.6 Regional Distribution Of Centres Of Plant Diversity And Endemic Bird Areas
Region Centres of Plant Diversity
# of SitesEndemic Bird Areas
# of SitesAfrica 33 32 Asia 83 63 Austalia / South Pacific 22 33 South America 46 42 Central America / Caribbean 23 31 North America 6 14 Europe and Middle East 21 6 Total 234 221 Source: adapted from WCMC (1992) and WWF and IUCN (1994). Selected sites must have one or both of the following characteristics: the area must clearly be species-rich, even if the number of species present is not yet accurately known, and/or it must be known to contain a large number of endemic species.
In addition, the evaluation process considers such other characteristics as whether the site a) contains diverse habitat types, b) contains plant genetic resources of economic importance, c) contains an unusual number of species adapted to special edaphic (soil) conditions, and d) is threatened or imminently threatened with extensive degradation (WWF and IUCN, 1994). In practice, the site selection process has emphasized botanical importance rather than threat, and distinctiveness rather than utility.
While a simple set of criteria and characteristics was used to help select initial sites for consideration, a deliberative and consultative process with regional botanical experts was used for the final selection rather than a quantitative ranking process. This helps to ensure that important areas for which data are not available are considered for the final list, as well as to update and strengthen the data collected for each site. Regional workshops in Africa, China, India, and North and South America reviewed and revised data on sites proposed by IUCN.
Endemic Bird Areas
Not long after the IUCN initiated the Centers of Plant Diversity project, the International Council for Bird Preservation (now known as Birdlife International) launched a similar effort to identify critical areas for the conservation of bird species around the world. It collected information on the geographic ranges of bird species, then mapped them to identify Endemic Bird Areas (EBAs), that is, areas having large numbers of endemic birds with restricted ranges. It also reviewed the endemism of other taxonomic groups within the Endemic Bird Areas to assess the value of birds as biodiversity indicators. The great advantage of using birds as an indicator for biodiversity - assuming there is correlation with species richness and endemism for other groups - is the abundant data collected by ornithologists and amateur bird watchers during the past century; these are useful for preparing distribution maps and other analysis.
Table 3.7 Countries With The Most Centres Of Plant Diversity Sites
Country # of Sites Indonesia 18 Malaysia 13 Brazil 12 Mexico 12 Australia 10 China 8 United States 8 Peru 8 Colombia 8 India 6 Philippines 6 Turkey 6 Source: adapted from WWF and IUCN (1994). To identify Endemic Bird Areas, locality records were gathered from ornithologists, museums, universities, and conservation agencies to identify species with breeding ranges of 50,000 km2 or less. Over 55,000 separate locality records were accurately geo-referenced and mapped using a computer-based Geographic Information System (GIS). The mapping yielded the surprising result that 27 percent of the world's approximately 9,600 bird species have breeding ranges restricted to less than 50,000 km2 (Bibby, et al., 1992). Not unexpectedly, species of restricted range tend to occur together, for instance on islands or in isolated mountain habitats. Using multivariate analysis, Birdlife International researchers developed boundaries around the groupings of the restricted-range endemic birds, designating these areas as Endemic Bird Areas. In all, 221 EBAs have been identified which contain the habitats of 2,484 restricted range endemic birds - or 95 percent of all known restricted-range species (see Table 3.8).
Most Endemic Bird Areas are found in the tropics (76 percent), with very few found in the northern temperate areas. Although the southern hemisphere has only about 25 percent of the world's land area (excluding Antarctica), it has more than half of the EBAs (119). Most of the EBAs are found either on islands (46 percent) or in mountainous habitats in continental areas.
The Endemic Bird Areas are nor uniform in size - the smallest (5km2) is found in the northwestern Hawaiian Islands, and the largest (174,000 km2) is in northern South America in French Guiana, Surinam, Guyana, and Brazil (Bibby et al., 1992). Although there is considerable variation in size, some patterns are evident. For example, all EBAs smaller than 1,000 km2 are found on islands and the larger EBAs tend to be continental. Only 16 percent of EBAs are larger than 50,000 km2, which is the maximum range size allowed for any one restricted-range endemic species.
Table 3.8 Countries With Greatest Number Of Endemic Bird Areas
Country # of Endemic
Bird Areas# of Restricted-Range
Bird Species1Indonesia 24 410 Peru 18 215 Brazil 17 200 Colombia 14 185 Mexico 14 105 China 12 60 Papau New Ginea 12 170 Ecuador 11 190 Philippines 9 115 Argentina 9 100 1 - Numbers are approximate.
Source: Adapted from Bibby et al. (1992)
Like size, the number of species contained in Endemic Bird Areas varies considerably beyond the two species minimum. There are an average of 11.2 restricted range species per EBA, but the numbers range from 2 in a number of locations (e.g., on Australia's Lord Howe Island) to 67 in the Solomon Islands. Most EBAs are found in predominantly forest habitats (70 percent), while fewer EBAs are found in predominantly scrub habitats (11 percent), or mixed habitats (11 percent). Grasslands and wetlands are poorly represented, most likely because species in these habitats are more widespread (WCMC, 1992).
Regardless of their location, restricted range-endemic bird species are frequently listed as threatened (29 percent), and most EBAs (85 percent) are known to contain threatened endemic species (Bibby et al., 1992).- only 8 percent of the land area found in EBAs is under any form of protection. Nearly one third of the individual EBAs have no protected areas coverage whatsoever, and 35 percent have less than 5 percent of their area legally protected (although nor necessarily in practice).
Bibby et al. (1992) also evaluated endemicity patterns for other groups of animals and plants to determine the level of congruence with bird species endemicity. In some parts of the world, there are striking similarities in patterns of endemicity - for example in Amazonia, there is a high degree of overlap between centers of endemism for birds, some lizards, butterflies, and trees. Overall, there appear to be some general patterns of congruence in endemism between birds and other taxonomic groups, but the overlap varies considerably from region to region, and distribution patterns for groups other than birds are poorly documented in most parts of the world.
Having identified the 221 Endemic Bird Areas, Bibby et al. (1992) took their analysis one step further. They classified the EBAs on the basis of their biological importance (species richness and endemism levels) and the immediacy of the threats they face. The EBAs were classified into three groups to indicate increasing level of biological importance (determined by the species to area relationship), and classified separately into another three groups by the degree of threat to the area.
Although the classifications are based on quantitative information, Bibby et al. (1992) were reluctant to use numerical ranking alone since it "gives an air of greater objectivity and finality than is appropriate." Rather, they evaluated the EBAs in each of the areas, giving scores of 1 to 3 on biological importance8 and 1 to 3 on degree of threat.9 These two classification systems are then combined into a conservation priority classification.
These two classification systems are then combined into a conservation priority classification. Those EBAs with a combined score of 5 or 6 are classified as "critical," those with a com-bined score of 4 are "urgent," and those with a combined score of 2 or 3 are "high" conservation priority. The final classification has 79 "critical" priority EBAs, 87 "urgent" EBAs, and 55 "high" priority EBAs.
The Bibby et al. (1992) analysis is one of the most comprehensive assessments of biodiversity conservation priorities ever made at a global scale. One hopes that similar efforts will be mounted for other taxonomic groups as more information becomes available.
The site selection approaches - centers of plant diversity and endemic bird areas - have the advantages of being relatively specific geographically, quantitatively based, and amenable to straightforward analysis. They also have their limitations. For example, restricting the analysis to birds with less than 50,000 km2 of range means that larger areas of avian endemism such as the Mediterranean Basin or Amazonia are not included. Similarly, wide-ranging migratory or sea birds that depend on a very confined breeding or wintering habitat are not included, even though such birds may be the most vulnerable of all. But, as Bibby et al. (1992) note, "the thrust of this report is not intended to deny that conservation action is needed in all the world's biomes. It is suggested that the smaller centers of endemism are the more pressing for conservation action because they are more susceptible to sufficient destruction to cause extinctions.