CONTENTS 



Page 



Highlights 63 



Introduction 63 



Diversity Loss 64 



Ecosystem Diversity 66 



Species Diversity 68 



Genetic Diversity 75 



Causes of Diversity Loss 78 



Development and Degradation 78 



Exploitation of Species 79 



Vulnerability of Isolated Species 80 



Complex Causes 80 



Conclusion 82 



Circumstantial Evidence 82 



Data for Decisionmaking 83 



Chapter 3 References 83 



Tables 



Table No. P^g^ 



3-1. Status of Animal Species in Selected Industrial Countries 72 



3-2. Summary of Data From Endangered Plant Species Lists 73 



3-3. Data on Threatened Plant Species of Selected Oceanic Islands 73 



3-4. Endangered African Cattle Breeds 75 



3-5. Crops Grown or Imported by the United States With a Combined 



Average Annual Value of $100 Million or More 77 



3-6. Oceanic Islands With More Than 50 Endemic Plant Species 81 



Figures 



Figure No. P^g^ 



3-1. Currently Described Species 64 



3-2. Changes in Wetlands Since the 1950s 66 



3-3. Past and Projected World Population 82 



Boxes 



Box No. P^ge 



3-A. Biological Concepts 65 



3-B. Typical Excerpts From Development Assistance Agency Reports 



Addressing Environmental Constraints to Development 69 



3-C. Definitions of Threatened Status 70 



