Endangered at What Level?

The functioning of the Endangered Species Act has been less effective than expected because remedial action is not triggered until populations are in serious trouble and because of the inadequacies of a species-by-species approach. These problems have stimulated interest in expanding the Act to protect endangered habitats, communities, and ecosystems. Such a development requires the existence of a generally agreed-upon classification system for these larger ecological units. No such classification system exists, and developing one will be difficult and politically contentious. © 1993 by the Ecological Society of America.