The scientists delved beyond species to identify genera and families that are unique to the hotspots, concluding that hotspots also hold a disproportionately high degree of unique evolutionary history. Madagascar and the Indian Ocean Islands Hotspot, for example, has 24 plant and vertebrate families that are found nowhere else on Earth. "We now know that by concentrating on the hotspots, we are not only protecting species, but deep lineages of evolutionary history," Mittermeier said. "These areas capture the uniqueness of life on Earth."
The hotspots concept was pioneered in 1988 by British ecologist Norman Myers, who recognized that hotspot ecosystems (most often in tropical forest areas) cover a small total land area yet account for a very high percentage of global biodiversity. The concept was subsequently refined by Myers and CI, most recently in 2000.
"This new analysis has benefited greatly from increased collaboration among countries and organizations, as well as from scientists' ever-increasing knowledge of species and their habitats," said Gustavo A.B. da Fonseca, executive vice president of CI.
Two factors determine which areas qualify as hotspots: number of endemic species (those found nowhere else) and degree of threat. Plants are used as a measure of endemism, and each of the hotspots holds at least half a percent of the total diversity of vascular plants as endemics; this translates to 1,500 species of vascular plants found exclusively within its boundaries. Degree of threat is determined by the percentage of remaining habitat, with each hotspot having lost at least 70 percent of its original natural habitat. Some of the hotspots have less than 10 percent of their original natural habitat.
THE HOTSPOTS ARE: