The national research agenda that Jim Carlton and Cheryl Ann Butman describe beginning on page 4 aims to fill in this deficit. Not an easy question. Sheer diversity itself may be of inestimable value as a foundation for a healthy planet and human well-being. Many ecologists now believe that richly diverse ecosystems are more resilient and better able to recover from such stresses as drought or human-induced habitat destruction than less diverse systems. Some describe biodiversity as nature's insurance policy against catastrophe.
Diminished diversity puts the functioning of ecosystems at risk.
The California Academy of Sciences, which operates a Biodiversity Resource Center, estimates that more than 10,000 species of terrestrial organisms become extinct each year, and the rate of extinction is increasing. The central cause of species extinction is human destruction of natural habitats. Of all the benefits we derive from biological resources ranging from medicine, to wood products, to recreational settings food is perhaps the most important. Five thousand plant species have been used as food by humans, but less than twenty now feed the majority of the world's population and just three or four carbohydrate crops are staples for a vast majority. One of the important benefits of conservation of biodiversity is the wild plant gene pool that is available to augment the narrow genetic base of these established food crops, providing disease resistance, improved productivity and different environmental tolerances.