Some pioneering projects in conservation biology are already reshaping scientists' ideas about extinction and its consequences. In the Amazon Basin near Manaus, Brazil, the World Wildlife Fund and Brazil's National Institute for Amazonian Research launched the Minima.! Critical Size of Eco systems project in 1979. Brazilian law re quires that 50 percent of the land in new cattle ranches remain forested; researchers worked with local ranchers as they cleared grazing land to create a set of forest reserves ranging in size from 1 to 10,000 hectares.
This huge experiment allows biologists to observe the process of extinction and species change when forest patches are isolated from once-continuous forest. The project will reveal for the first time the rates and patterns of species loss as the ecosystem approaches new equilibrium populations of plants and animals. Similar studies are needed in every type of habitat on every continent—a goal beyond the present ...
