3.2 Biodiversity and protected areas See Table 3.2 here

Commentary
About the data
Definitons
Data Sources

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Losses of biodiversity are irreversible, and they compromise the choices of both current and future generations. Biologically diverse ecosystems often contain economically useful products that can be harvested or used as inputs in production—they provide economically valuable services, such as:

Improving the quality of water available for agriculture, industry, or human consumption. Reducing sedimentation in reservoirs and irrigation works. Minimizing floods, landslides, coastal erosion, and droughts. Providing recreational opportunities. Filtering excess nutrients. Providing essential habitats for economically important species.

Ecosystems also are the reservoirs of genetic material from which new pharmaceuticals and improved crops are developed. And many people value ecosystems even if they do not use them.

The main cause of biodiversity loss has been habitat destruction, driven by such human activities as logging and by shifts in land use to agriculture, infrastructure development, or human settlement. Agriculture has played a major role in this process as the human activity that affects the largest portion of the earth’s surface and the biggest user of freshwater worldwide. Agricultural expansion and intensification are both potentially important contributors to habitat and biodiversity losses worldwide. Conversion of land to agriculture is closely related to logging: many logged areas are later cultivated, and roads built for logging facilitate new settlement.

Conversion of habitat can lead directly to the extinction of species. Even if species survive the conversion of part of their habitat, their long-term survival may be threatened by fragmentation and disturbance of the rest. As habitats become smaller, the number of species they can support falls, and the populations of wide-ranging species often expand at the expense of species with more specialized habitat requirements. Species also are threatened by toxic chemicals and by changes in water regimes caused by human use.

Habitat conservation is vital for stemming the decline of biodiversity. Habitat conservation efforts traditionally have centered on protected areas, which have grown substantially in recent decades, particularly in low- and middle-income countries. Almost 7 percent of the world’s land area is protected (figure 3.2a), with the proportion highest in North and Central America (table 3.2a). Although protected areas are important in conserving biodiversity, they have limits. Many are subject to encroachment and disturbance. Most were established to protect scenic or recreational resources, with ecosystem protection only recently becoming an explicit objective.

Recognition of the limits of protected areas has spurred efforts to foster complementarities between biodiversity protection and economic activities. Such complementarities are particularly important for agriculture, which depends on many services provided by the environment, such as crop pollination and genes for developing improved crop varieties and livestock breeds. Moreover, exploiting biodiversity could substantially boost agricultural production. At the same time, damage to biodiversity often hurts agriculture. Reconciling biodiversity conservation with increased production to meet the needs of a growing human population will be a major challenge.

Source: Table 3.2.

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The data here are subject to variations in definition and in reporting to the World Conservation Monitoring Centre (WCMC)—a joint venture of the United Nations Environment Programme (UNEP), World Wide Fund for Nature (WWF), and World Conservation Union (IUCN)—which compiles and disseminates them. As a result cross-country comparability is limited. Compounding these problems, available data are of different vintages.

Nationally protected areas are areas of at least 1,000 hectares that fall into one of five management categories defined by the WCMC:

Scientific reserves and strict nature reserves with limited public access. National parks of national or international significance (not materially affected by human activity). Natural monuments and natural landscapes with unique aspects. Managed nature reserves and wildlife sanctuaries. Protected landscapes and seascapes (which may include cultural landscapes).

The first three categories, referred to as "totally protected," are areas maintained in a natural state and closed to extractive uses. The last two categories, referred to as "partially protected," are areas that may be managed for specific uses, such as recreation or tourism, or that provide optimum conditions for certain species or communities of wildlife. Some extractive use is allowed within these areas. Designating land as a protected area does not necessarily mean, however, that protection is in force.

Threatened species are defined according to the IUCN’s classification categories: endangered (in danger of extinction and survival unlikely if causal factors continue operating), vulnerable (likely to move into the endangered category in the near future if causal factors continue operating), rare (not endangered or vulnerable, but at risk), indeterminate (known to be endangered, vulnerable, or rare but not enough information is available to say which), out of danger (formerly included in one of the above categories, but now considered relatively secure because appropriate conservation measures are in effect), and insufficiently known (suspected but not definitely known to belong to any of the above categories). Figures on species are not necessarily comparable across countries because taxonomic concepts and coverage vary. And while the number of mammals and birds is fairly well known, it is difficult to make an accurate account of plants.

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• Nationally protected areas are totally or partially protected areas of at least 1,000 hectares that are designed as scientific reserves with limited public access, national parks, natural monuments, nature reserves or wildlife sanctuaries, and protected landscapes and seascapes. The data do not include sites protected under local or provincial law. Total land area is used to calculate the percentage of total area protected (see table 3.1).

• Mammals exclude whales and porpoises.

• Birds are listed for countries included within their breeding or wintering ranges.

• Higher plants refer to native vascular plant species.

• Threatened species refer to species classified according to the IUCN categories endangered, vulnerable, rare, indeterminate, out of danger, and insufficiently known.

Data on protected areas are from the Protected Areas Data Unit of the WCMC, and those on species are from the WCMC’s Biodiversity Data Sourcebook, the WCMC’s Global Biodiversity Status of the Earth’s Living Resources, and the IUCN’s 1994 Red List of Threatened Animals, as reported by the World Resources Institute.

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