2004 IUCN Red List of Threatened Species - A Global Species

3,73

MB

Assessment

217

stron

2351

ID

World Conservation Union

2004

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Contents

Foreword xi

Preface xiii

Acknowledgements xv

Executive Summary xxi

Section 1. Introduction 1

Section 2. Globally Threatened Species 5

2.1 Introduction: the Current Status 6

2.2 How Little is Known: the Number of Described Species and the Number Evaluated 6

2.3 How Many Threatened Animal Species are There? 10

2.3.1 Threatened Vertebrates 10

2.3.1.1 Mammals, Birds and Amphibians 10

2.3.1.2 Reptiles 19

2.3.1.3 Fishes 21

2.3.2 Threatened Invertebrates 25

2.4 How Many Threatened Plants are There? 27

2.5 Other Taxonomic Groups 31

Section 3. Extinctions in Recent Time 33

3.1 Introduction 34

3.2 Current Extinctions 34

3.3 Extinct Species that Survive Ex Situ 40

3.4 What is the Rate of Extinction? 41

3.5 Which Taxonomic Groups are Most Prone to Extinction? 42

3.6 Where have Extinctions Occurred? 42

3.7 What are the Causes of Extinction? 45

3.8 Documented Extinctions over the Past 20 Years 46

Section 4. Trends in the Status of Threatened Species 51

4.1 Introduction 52

4.2 Red List Indices for Birds 1988–2004 52

4.2.1 The Red List Index for All Birds 52

4.2.2 The Red List Index for Birds by Realm and Ecosystem 53

4.2.3 The Red List Index for Birds by Family 55

4.3 Preliminary Red List Index for Amphibians 1980–2004 (Retrospectively Assessed) 56

4.3.1 Preliminary Red List Index for All Amphibians 56

4.3.2 Preliminary Red List Index for Amphibians by Realm and Ecosystem 57

4.3.3 Preliminary Red List Index for Amphibian Families 59

4.4 Comparison of Red List Indices for Birds and Amphibians 59

4.4.1 Trends in the Status of the Most Threatened Birds and Amphibians 59

4.5 Trends for Other Taxonomic Groups 61

Section 5. Geography of the Red List 63

5.1 Introduction 64

5.2 Mapping Species to Predetermined Geographic Units 64

5.2.1 Countries 64

5.2.2 Ecological Systems 65

5.2.3 Biogeographic Realms 66

5.2.4 Biomes 69

5.2.5 Habitats 71

5.3 Mapping Species’ Extent of Occurrences 72

5.3.1 Species Richness 72

5.3.2 Restricted-Range Species 73

5.3.3 Threatened Species Richness 74

5.4 Mapping Species to the Locality Scale 80

Section 6. The Many Causes of Threat 85

6.1 Introduction 86

6.2 Habitat Destruction and Degradation 87

6.3 Over-Exploitation 90

6.4 Invasive Alien Species 92

6.5 Disease 94

6.6 Pollution and Contaminants 96

6.7 Incidental Mortality 96

6.8 Climate Change 97

6.9 Other Threats 97

6.10 Threatening Processes and Patterns of Extinction 100

6.10.1 Spatial Variation in Threats 100

6.10.2 Temporal Variation in Threats 101

6.10.3 Intrinsic Vulnerability 101

6.10.4 Extinction Filters 102

6.10.5 Extinction Lags 102

Section 7. The Social and Economic Context of the Red List 105

7.1 Introduction 106

7.2 Human Population 106

7.2.1 Current Population Density 106

7.2.2 Population Growth 107

7.3 Economic Factors 109

Section 8. Conservation Responses 111

8.1 Introduction 112

8.2 Research Action 112

8.3 Communication and Education 116

8.4 Policy-Based Actions 118

8.5 Habitat and Site-Based Actions 121

8.6 Species-Based Actions 129

Section 9. Conclusions 135

9.1 The IUCN Red List and the 2010 Target 136

9.2 How is the State of Biodiversity Changing? 136

9.3 Which Species are in Trouble? 137

9.4 Where is the Threat of Extinction Greatest? 138

9.4.1 Geopolitical Units 138

9.4.2 Ecological Systems 138

9.4.3 Areas of Species Richness 138

9.5 What are the Main Pressures? 139

9.6 Which are the Most Pressing Research Needs? 139

9.7 What Responses are in Place? 140

Section 10. References 141

Appendices 153

Appendix 1: The IUCN Red List Programme 154

1.1 Global Assessments: Introduction 154

1.1.1 The Global Amphibian Assessment (GAA) 154

1.1.2 The Global Mammal Assessment (GMA) 155

1.1.3 The Global Reptile Assessment (GRA) 156

1.1.4 Freshwater Biodiversity Assessment Programme 156

1.1.5 The Global Marine Species Assessment 157

1.1.6 The Global Plant Assessment 157

1.1.7 State of the World’s Birds 158

1.2 Regional Red Lists 159

1.3 Red List Programme Future Goals 159

Appendix 2: Methodology 160

2a. General 160

2b. Globally Threatened Species 163

2c. Extinction 164

2d. Trends 165

2e. Geography of the Red List 166

2f. Threats 167

2g. The Social and Economic Context of the Red List 169

2h. Conservation Responses 169

Appendix 3: Summary Data 170

3a. Changes in total numbers of threatened species (CR, EN and VU) by major taxonomic group

since 1996 (1998 for plants) 170

3b. Changes in numbers of species in each threatened category (CR, EN and VU) by major

taxonomic group since 1996 (1998 for plants) 171

3c. Mammal orders more or less threatened than expected, relative to the average for mammals as

a whole 172

3d. Mammal families more or less threatened than expected, relative to the average for mammals

as a whole 173

3e. Bird orders more or less threatened than expected, relative to the average for birds as a whole

177

3f. Bird families more or less threatened than expected, relative to the average for birds as a whole

178

3g. Amphibian orders more or less threatened than expected, relative to the average for amphibians

as a whole 182

3h. Amphibian families more or less threatened than expected, relative to the average for

amphibians as a whole 182

3i. Changes in numbers of Extinct (EX) and Extinct in the Wild (EW) species by major taxonomic

group since 1996 (1998 for plants) 184

3j. The numbers of threatened species present and threatened species endemic per country for

mammals, birds, amphibians, turtles, chondrichthyan fishes (elasmobranches), conifers and

cycads 185