Science and the Endangered Species Act -- Copyright -- Preface -- Contents -- Executive Summary -- INTRODUCTION -- THE PRESENT STUDY -- EXTINCTIONS -- THE SPECIES CONCEPT -- HABITAT -- RECOVERY -- CONSERVATION CONFLICTS BETWEEN SPECIES -- ESTIMATING RISK -- MAKING ESA DECISIONS IN THE FACE OF UNCERTAINTY -- TIMING -- BEYOND THE ENDANGERED SPECIES ACT -- SCIENCE, POLICY, AND THE ESA -- 1 Introduction -- HISTORY -- THE PRESENT STUDY -- REFERENCES -- 2 Species Extinctions -- EXTINCTIONS OVER GEOLOGICAL TIME -- PREHISTORIC HUMAN IMPACT ON CONTINENTAL ECOSYSTEMS -- PREHISTORIC HUMAN IMPACT ON ISLAND ECOSYSTEMS -- RELATING THE PAST TO THE PRESENT -- Ecosystem Degradation and Restoration -- Rates of Extinction -- Habitat Loss -- Introduced Species -- CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- 3 Species Definitions and the Endangered Species Act -- HISTORICAL USE OF THE TERM SPECIES IN IMPLEMENTATION OF THE ENDANGERED SPECIES ACT -- Introduction -- Zoological Interpretations of Species -- Botanical Interpretations of Species -- HISTORY OF SPECIES CONCEPTS BEFORE AND AFTER THE ENDANGERED SPECIES ACT -- Species Concepts -- Taxonomic Units Below the Rank of Species -- A CONCEPT OF SPECIES FOR THE PURPOSES OF THE ENDANGERED SPECIES ACT -- Introduction -- Evolutionary Units and Their Identification -- Species and Subspecies -- Distinct Population Segments -- Distinctiveness -- Genetic Isolation -- Geographic and Temporal Isolation -- Behavioral and Reproductive Isolation -- Examples of Circumscription of Evolutionary Units -- The Fate of Hybrids under the Evolutionary Unit Concept -- CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- 4 The Role of Habitat Conservation and Recovery Planning -- THE IMPORTANCE OF HABITAT -- THE ROLE OF HABITAT CONSERVATION UNDER THE ESA -- CRITICAL HABITAT AND FEDERAL ACTIVITIES -- Survival Habitat.

PRIVATE ACTIVITIES AND HABITAT CONSERVATION PLANNING -- Habitat-Conservation Plans -- RECOVERY PLANNING -- NATURAL COMMUNITY CONSERVATION PROGRAM AND COASTAL SAGE SCRUB COMMUNITY OF SOUTHERN CALIFORNIA -- HABITAT-RELATED STANDARDS -- Public and Private Lands and Actions -- Survival and Recovery -- CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- 5 Modern Perspectives of Habitat -- LANDSCAPES AND POPULATIONS -- SOURCES AND SINKS -- METAPOPULATIONS -- SPATIALLY EXPLICIT MODELS -- A SPATIAL PERSPECTIVE AND POPULATION VIABILITY ANALYSIS -- CONCLUSIONS -- REFERENCES -- 6 Conservation Conflicts Between Species -- INTERACTIONS OF SPECIES IN NATURE -- NORTHERN GOSHAWK AND MEXICAN SPOTTED OWL -- WINTER-RUN CHINOOK SALMON AND DELTA SMELT -- BACHMAN'S SPARROW AND RED-COCKADED WOODPECKER -- MARINE MAMMALS AND SALMONIDS -- CONCLUSIONS -- RECOMMENDATIONS -- REFERENCES -- 7 Estimating Risk -- ESTIMATING THE RISK OF EXTINCTION -- SOURCES OF RISK -- Random Demographic Changes -- Random Environmental Changes -- Catastrophes -- Accumulation of Deleterious Genetic Factors -- Loss of Adaptive Variation Within Populations -- Habitat Fragmentation -- Supplementation -- FOCUSING CONSERVATION EFFORTS -- DISTRIBUTION OF EXTINCTION TIMES -- LIMITATIONS OF OUR ABILITY TO ESTIMATE RISK -- CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- 8 Making ESA Decisions in the Face of Uncertainty -- DECISIONS REQUIRED UNDER THE ESA -- THE NEED FOR NEW APPROACHES TO DECISION MAKING -- PROVIDING OBJECTIVE RISK STANDARDS -- Developing Quantitative Risk Standards -- Time Frame for Estimating Risk of Extinction -- Listing Systems Based on Objective Criteria and Rules -- Limitations on Estimates of Risk -- Limits of Models -- Poor Understanding of Cumulative Effects and Thresholds -- Should Different Risk Standards Apply to Different ESA Decisions? -- Endangered, Threatened, Recovered.

Different Taxa -- Public Versus Private Land -- USING STRUCTURED APPROACHES TO DECISION MAKING -- Using Subjective Probability and Expert Opinion -- Linking Science and Values -- Scientific Uncertainty in ESA Decisions -- Estimating Uncertain Quantities -- Reducing Uncertainty by Gathering Information -- Types of Errors -- Burden of Proof -- Statistical Errors -- Cumulative Effects/Thresholds -- Listing Decisions -- Reducing Asymmetry of Risk for Listed Species -- Making Tradeoffs Among Competing Objectives -- Resolving Conflicts Among Interest Groups -- Implementing Structured Approaches in the Agencies -- CONCLUSIONS AND RECOMMENDATIONS -- REFERENCES -- 9 Areas of Scientific Uncertainty -- ECOSYSTEM-BASED PROTECTION -- Ecosystem Management -- INADEQUATE KNOWLEDGE OF SPECIES AND THEIR ROLES IN ECOSYSTEMS -- ESTIMATION OF THE RISK OF EXTINCTION -- Current Limitations of Existing Theory -- Intrinsic Limits of Extinction Models -- LACK OF BASIC INFORMATION -- Dynamics of Natural Populations -- Systematics -- Do Minimum Viable Population Sizes Exist? -- THE PROTECTION OF GENETIC DIVERSITY -- Uncertainty Regarding Future Adaptive Challenges to Species -- FEASIBLE MANAGEMENT STRATEGIES -- The Spatial Structure of Reserves -- Corridors and Edge Effects -- Reconstruction of Habitat -- Consequences of Captive Breeding and Supplementation -- Global Environmental Change -- VALUING RARITY -- REFERENCES -- 10 Beyond the Endangered Species Act -- IS THE ESA WORKING? -- REDUCING EXTINCTION -- RECOVERY SUCCESS -- PROTECTION OF ECOSYSTEMS -- THE FUTURE: BEYOND THE ENDANGERED SPECIES ACT -- SCIENCE, POLICY, AND THE ESA -- REFERENCES -- Appendixes -- Appendix A -- Appendix B -- Endangered Species Act of 1973 -- Table of Contents -- Endangered Species Act of 1973 -- Findings, Purposes, and Policy -- Definitions.

Determination of Endangered Species and Threatened Species -- Land Acquisition -- Cooperation with the States -- Interagency Cooperation -- International Cooperation -- Convention Implementation -- Prohibited Acts -- Exceptions -- Penalties and Enforcement -- Endangered Plants -- Conforming Amendments -- Repealer -- Authorization of Appropriations -- Effective Date -- Marine Mammal Protection Act of 1972 -- Annual Cost Analysis by the Fish and Wildlife Service -- Appendix C Biographical Information on Committee Members -- Chair -- Members -- Staff -- Index.