BIOLOGICAL DIVERSITY, ECOSYSTEMS, AND THE HUMAN SCALE

This paper considers the significance of biological diversity in relat ion to large-scale processes in complex and dynamic ecological-economi c systems. It focuses on functional diversity, and its relation to pro duction and maintenance of ecological services that underpin human soc ieties. Within functional groups of organisms two important categories of species are identified: keystone process species and those essenti al for ecosystem resilience. The latter group represents ''natural ins urance capital.'' In addition to basic research on the interplay among biological diversity, functional performance, and resilience in compl ex self-organizing systems, we suggest that a functional approach has two main implications for a strategy for biodiversity conservation: (1 ) Biodiversity conservation to assure the resilience of ecosystems is required for all systems, no matter how heavily impacted they are. It should not be limited to protected areas. (2) The social, cultural, an d economic driving forces in society that cause biodiversity loss need to be addressed directly. Specifically, (a) differences between the v alue of biological diversity to the private individual and its fundame ntal value to society as a whole need to be removed; (b) social and ec onomic policies that encourage biodiversity loss should be reformed, e specially where there is a risk of irreversible damage to ecosystems a nd diversity; and (c) institutions that are adaptive and work in syner gy with ecosystem processes and functions are critical and should be c reated at all levels.