Setting priorities for conservation.

• Author: Bright, Chris
• Position: Brief Article

44 percent of all vascular plant species and 35 percent of all terrestrial vertebrate species appear to be confined to just 25 "hotspots," which cover only 1.4 percent of the Earth's land surface, according to a paper published in the 24 February 2000 issue of Nature. "Biodiversity Hotspots for Conservation Priorities," written by a team of five ecologists, finds that these hotspots are all under a high degree of threat, so protecting them presents a major opportunity for a highly targeted, global conservation effort.

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...