Setting priorities for conservation.
The authors define a hotspot as an ecologically distinct bioregion that meets two criteria. First, it must be biologically rich, containing at least 0.5 percent (or 1,500) of the world's vascular plants as endemics--that is, as species native only to the area concerned. (Some 90 percent of the world's flora consists of "vascular" plants--plants that have internal "plumbing.") Second, the region must have suffered loss of at least 70 percent of the original vegetation--a strong indication that surviving habitat is under severe pressure. Animal endemics were not used to define the hotspots, but the authors surveyed endemic fauna to determine the degree of overlap between plant and animal diversity, and to aid comparison of the hotspots themselves. The 25 hotspots are the sole surviving ranges of 29 percent of the world's birds, 27 percent of mammals, 38 percent of reptiles, and 53 percent of amphibians. (These percentages refer only to endemics; the hotspots also contain many species of both animals and plants that are not endemic to them.)
Of the 25 hotspots, 15 are tropical. Nine are made up largely or entirely of islands--and virtually all tropical islands are included in one hotspot or another. The hotspots vary in size from the surviving original cover of the entirety of southeast Asia and central America, to the 2,000 square kilometers of forest remaining along the eastern Kenya-Tanzania border.
Although the analysis is still limited--it doesn't include invertebrates, for example, or marine vertebrates--the authors argue that it is comprehensive enough to justify a substantial expansion of the original hotspots conservation strategy. That strategy, launched in 1989. was based solely on plant diversity "hotspots" and has attracted some $400 million in funding over roughly a decade. The current paper argues for increasing the level of finding to $500 million annually for the next five years--a tiny fraction of the $300 billion annually that a comprehensive global conservation program would probably cost.
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|Article Type:||Brief Article|
|Date:||Jul 1, 2000|
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