Biodiversity is the array of populations and species on Earth, and the communities, ecosystems and landscapes of which they are component parts. Extinction may threaten local populations or entire species. While attention has focused on the problem of species loss, in many parts of the world the loss of local populations may be the most important aspect of the degradation of biodiversity. This paper discusses the importance of population extinction relative to species extinction, offers a preliminary assessment of its importance, and examines policy implications.
