Protected areas usually are designated and managed to keep wild species that live within the area from becoming extinct. Even after an area has been set aside as protected habitat, extinction or population declines may still occur as a result of changes in environmental conditions related to climate change, land use in surrounding areas, or widespread pollution. Climate change is likely to induce vegetation change that will force wild plant and animal species to shift their distribution in response to the new conditions. For example, a variety of changes in butterflies, dragonflies, beetles, and other migratory insects have been recorded in green corridors of Japan in recent years (Ubukata, 2000), and shifts have been recorded in the ranges of many North American, European, Arctic, and Antarctic bird and insect species (see Section 5.4). If the protected area is not large enough to contain an area that will be suitable under the new climate conditions, a species may become locally extinct. In contrast, protected areas that are large enough to cover an elevation or a latitudinal gradient should allow species to make adjustments along the gradient as conditions change. In some cases, such as in coastal areas, habitat may simply be lost as a result of factors such as sea-level rise, with no potential area for species to migrate.
Frontier forests in Asia are home to more than 50% of the world's terrestrial plant and animal species (Rice, 1998). Risks to this rich array of living species are increasing. For instance, of the 436 species of mammals and 1,500 species of birds in Indonesia, more than 100 species each of mammals and birds have been declared threatened (UNEP, 1999). Similar trends also are seen in China, India, Malaysia, Myanmar, and Thailand. In India, as many as 1,256 higher plant species, of more than 15,000 species, are threatened (Sukumar et al., 1995).
Coastal areas are likely to be at risk from climate change-induced sea-level rise. A rise in the water level of estuaries will reduce the size and connectedness of small islands and coastal and estuarine reserves and increase their isolation. The Yangtze (Changjiang) and Mekong deltas on mainland China and the Mai Po marshes in Hong Kong are refueling stops for migratory birds, especially ducks, geese, and shorebirds. The presence of these birds may be threatened by the disappearance of coastal marshes as a result of increases in sea level from global warming (Li et al., 1991; Tang, 1995). Similarly, the Rann of Kutch in India supports one of the largest Greater Flamingo colonies in Asia (Ali, 1985; Bapat, 1992). With sea-level rise, these salt marshes and mudflats are likely to be submerged (Bandyopadhyay, 1993), which would result in decreased habitat for breeding flamingoes and lesser floricans (Sankaran et al., 1992). In addition, about 2,000 Indian wild asses in the Rann of Kutch could lose their only habitat in India to rising sea level (Clark and Duncan, 1992).
The Sundarbans of Bangladesh, which support a diversity of wildlife, are at great risk from rising sea level. These coastal mangrove forests provide habitat for species such as Bengal tigers, Indian otters, spotted deer, wild boars, estuarine crocodiles, fiddler crabs, mud crabs, three marine lizard species, and five marine turtle species (Green, 1990). With a 1-m rise in sea level, the Sundarbans are likely to disappear, which may spell the demise of the tiger and other wildlife (Smith et al., 1998).
Species that live in mountainous areas also are particularly at risk of losing habitat as a result of changes in climate. Extreme temperature conditions may cause these protected areas to undergo major changes, partly because of high rates of variation in habitat structure that naturally occur on mountain ranges as a result of changes in slope, steepness, and exposure. Protected areas also may be subjected to extreme surface runoffs because of rapid melting of winter snow. Because many Asian mountain ranges are east-west oriented, there will be little room for species to shift their ranges toward cooler mountainous habitat. An additional barrier to wildlife movements in mountainous habitat derives from the fact that many of the larger reserves in central Asia are located along international borders. Depending on topography, if these borders are heavily fenced, most of the larger terrestrial vertebrates will not be able to respond spatially to changes in their environment.
Besides loss of habitat, wild species are at risk from changes in environmental conditions that favor forest fires and drought. For example, forest fires under unseasonably high temperatures in Nepal may threaten local extinction for red pandas, leopards, monkeys, deer, bears, and other wild animals. If the frequency of these extreme events increases, the frequency of fire also may increase. Similarly, increases in the frequency of dry spells and local droughts may decrease populations. For example, drought-related decreases in the density and persistence of Green Leaf Warblers have been recorded on their wintering grounds in the Western Ghats of south India (Katti and Price, 1996). In desert ecosystems, protected areas often are located around oases, which are the basis for the existence of much of the local fauna. Protected oases often are far apart, so droughts that cause a decline in local forage often cause mass mortality because animals may not be able to move on to adjacent oases. The frequency of these droughts therefore is a key component in the viability of populations in such protected areas (Safriel, 1993).
Climate change is likely to act synergistically with many other stressors, such as land conversion and pollution, leading to major impacts on protected areas and species (see Chapter 5). Currently designated major protected areas in Asia need to be examined with respect to the ability of their species to shift in range in response to changing climate, as well as with respect to how much habitat could be lost. Many speciesespecially those in coastal areas and mountainous habitatscould experience large population declines; some may become extinct at least in part because of climate changes.
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