ABSTRACT
Ecologists have proposed several indicators of sustainability. Unlike economic valuation approaches, ecological indicators are not concerned with measuring the impacts of environmental degradation on human welfare. This chapter examines the use of different concepts of ecological resilience and stability as important indicators of sustainability. It looks at indicators of species richness and extinction as key ecological measures for use in sustainable development policy. The economist Martin Weitzman has argued that, if any biodiversity indicator is to be truly useful for policy purposes, then at some point it must be translated into a value of diversity function. C. Perrings et al use the example of wild and domesticated grasses in rangeland systems to argue how different considerations of the ecological and economic roles of these species can determine whether increased species diversity is necessarily a good thing. Although the loss of biological diversity may take many forms, the extinction of species is taken to represent its most dramatic and irreversible manifestation.
