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The ability of wildlife to adapt naturally to climate change is largely a function of available genetic diversity and the rate of change. This section deals not with natural adaptation but with human adaptation to changes in wildlife populations, in terms of conserving wildlife and replacing some of the goods and services that wildlife provides.
One typical method to adapt to declines in wildlife populations has been establishment of refuges, parks, and reserves. Placement of reserves, however, rarely has taken into account potential rapid climate change, even though the problems of such change and reserve placement were discussed in the mid-1980s (Peters and Darling, 1985). Managers of current reserves and parks need to be encouraged to consider rapid climate change in developing future management plans (Solomon, 1994; Halpin, 1997). Developing a series of bioindicators to monitor the potential impacts of rapid climate change on parks and reserves may be possible (de Groot and Ketner, 1994).
In the United Kingdom, the Institute of Terrestrial Ecology has estimated that 10% of all designated areas (i.e., nature reserves) could be lost (e.g., to habitat degradation) within 30-40 years and that species distribution in 50% of designated areas could change significantly over the same period (UK DETR, 1999). In light of these changes, there is a need for a robust nature conservation system that can accommodate climate change.
In part, the disparity between siting reserves where wildlife species currently are versus where they may be in the future may stem from uncertainties in the rate and amount of projected climate change. If a species' range shifts out of a reserve created for its survival, the current reserve placement could even be considered maladaptive. However, if reserves are not created and species are lost to other pressures, the potential effects of climate change on species distributions are moot (see Box 5-7).
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Box 5-7. Biodiversity Hotspots and Climate Change
Biodiversity hotspots are areas with exceptional concentrations of endemic species facing extraordinary threats of habitat destruction. Twenty-five hotspots contain the sole remaining habitats for 133,149 (44%) vascular land plants and 9,732 (36%) terrestrial vertebrates (Myers et al., 2000). The number of invertebrates is not known, but in light of the many interactions (e.g., pollination) between plants and invertebrates, especially insects, the concentrations of these animals probably parallel those of plants. Nine of these hot spots occur on islands, making them particularly vulnerable to sea-level rise and limiting or preventing the opportunity for many terrestrial animals to modify their range (Myers et al., 2000). Because these 25 hotspots constitute only 1.4% of the Earth's land surface (Myers et al., 2000), they provide an opportunity for planners to respond to the biodiversity crisis by giving priority status to conserving them. Unfortunately, synergistic effects of climate change and requirements to conserve areas for species survival may complicate the situation. With warming temperatures, many species are expected to move poleward (Parmesan et al., 1999) or upward in altitude (Pounds et al., 1999). This implies that the locations of hotspot reserves may need to allow for such movement, which may require a somewhat larger region to be conserved. Even with these efforts, some species may not be conserved because they presently are as far poleward (e.g., fynbos region at the southern tip of South Africa) or as high in altitude (e.g., cloud forests in Costa Rica) as they can be. |
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