Comprehensive resource highlighting the nation's biological wealth and concerns. It identifies causes for the decline of some species and habitats; describes successful management strategies that have helped recover some declining species and habitats; provides the scientific information neccessary to help manage and conserve the nation's biological resources; gives statistically reliable information on the status and trends in biological resources; identifies factors that have caused biological changes; analyzes how natural forces and human activity affect biological resources; and looks at alternative management and policy decisions that might help improve the use of biological resources.