Decline and Recovery of the Island Fox: A Case Study for Population Recovery

by Timothy J. Coonan, Catherin A. Schwemm, David K. Garcelon

Overview

Native only to the California Channel Islands, the island fox is the smallest canid in North America. Populations on four of the islands were threatened to extinction in the 1990s due to human-mediated predation and disease. This is the first account of the natural history and ecology of the island fox, illustrating both the vulnerability of island ecosystems and the efficacy of cooperative conservation measures. It explains in detail the intense conservation actions required to recover fox populations, such as captive breeding and reintroduction, and large-scale ecosystem manipulation. These actions were successful due in large part to extraordinary collaboration among the scientists, managers and public advocates involved in the recovery effort. The book also examines the role of some aspects of island fox biology, characteristic of the ‘island syndrome’, in facilitating their recovery, including high productivity and an apparent adaptation to periodic genetic bottlenecks.

Product Details

ISBN-13:	9780521887113
Publisher:	Cambridge University Press
Publication date:	07/22/2010
Series:	Ecology, Biodiversity and Conservation
Pages:	228
Product dimensions:	6.00(w) x 9.00(h) x 0.60(d)

About the Author

Cathy Schwemm is a lecturer at California State University, Channel Islands in the Department of Environmental Science and Resource Management, and runs her own ecological consulting company. She obtained her BS from Colorado State University, her MS from California State University, Northridge, and her Ph.D. from the University of California, Santa Barbara. Cathy worked for the National Park Service for nearly 20 years, including 14 years at Channel Islands National Park. In 1993 she began the island fox monitoring program for the Park Service, and has been a member of the Island Fox Conservation Working Group since 1999. In 2005 she and Dave Garcelon co-edited the Proceedings of the Sixth California Island Symposium. She currently serves on the board of directors of Friends of the Island Fox.

Tim Coonan is a biologist for the US National Park Service at Channel Islands National Park, where he has directed the terrestrial monitoring and restoration programs since 1992. He has been studying island foxes for 17 years. Since 1999 Tim has directed the park's island fox recovery program and has led the multi-agency Island Fox Conservation Working Group. Tim's efforts to recover island foxes have been recognized by the National Park Service, who twice named him as its Pacific West Region Natural Resource Manager of the Year. Tim has authored or co-authored over 25 publications on island foxes. Tim holds a BS in Biology from the University of Notre Dame, and an MS in Biology from Northern Arizona University. Tim has worked for the National Park Service for over 25 years. Prior to his work at Channel Islands National Park Tim worked at Death Valley National Park, where he studied desert bighorn and pupfish.

David Garcelon is the founder and President of the Institute for Wildlife Studies, headquartered in Arcata, California. He has been involved in conservation programs around the world, including Japan, Russia, Swaziland, Kazakhstan, and the Mariana Islands. He holds an MS degree in Wildlife Management from Humboldt State University where he is an associate faculty member and both lectures and serves on graduate committees. David began studying island foxes in 1988 and has worked with all of the six subspecies. His research has included long-term work on population demography, captive breeding, movement patterns, disease exposure, and behavior. Along with the Center for Biological Diversity he co-signed the petition to the U.S. Fish and Wildlife Service to provide federal protection for four species of the island fox under the Endangered Species Act. David sponsored the first meeting of experts to examine the data associated with population declines of island foxes on the northern Channel Islands and has been active in the Island Fox Working Group since its inception. He continues to be involved in research and recovery efforts for the island fox, as well as several other federally listed species such as the San Clemente loggerhead shrike, San Clemente sage sparrow, and desert tortoise. David is currently working to restore wolverine populations in California and is helping develop new techniques for monitoring wildlife populations using automated telemetry.

Table of Contents

Foreword xii

Acknowledgments xiv

1 Introduction 1

2 Evolution and genetics 5

2.1 Description 5

2.2 Dwarfism and the island syndrome 7

2.3 Evolution of the island fox 8

2.4 Island foxes in the paleoenvironment 12

2.5 The peculiar genetic status of the island fox 13

2.6 Genetic management of captive island foxes 15

2.7 Future of wild populations 20

3 Social structure, reproduction, mortality and survivorship, and population dynamics 21

3.1 Social organization and reproductive behavior 22

3.2 Mortality and survivorship 24

3.3 Population abundance and dynamics 27

3.4 Factors affecting population dynamics 30

3.5 Modeling island fox population dynamics 32

3.6 Summary 33

4 Food habits, habitat use, activity patterns, and dispersal 34

4.1 Food habits 34

4.2 Dispersal and travel 38

4.3 Home range 39

4.4 Habitat use 40

4.5 Activity patterns 41

4.6 Summary 42

5 Golden eagles and the decline on the northern islands 43

5.1 Detecting change 43

5.2 Determining the cause 47

5.3 Golden eagle colonization of the northern islands 50

5.4 The vulnerability of island foxes to diurnal aerial predators 56

6 Ecosystem recovery: Predators and prey on the northern Channel Islands 58

6.1 Golden eagle removal 58

6.2 Long-term ecosystem recovery actions 66

6.3 Summary 71

7 Disease and decline on Santa Catalina Island 73

7.1 Declining populations 73

7.2 Initial results 75

7.3 Was disease the cause of the decline? 75

7.4 Recommendations for population recovery 76

7.5 Testing CDV vaccine 77

8 Recovery actions: Captive breeding of island foxes 81

8.1 Captive breeding efforts on the northern islands 81

8.2 Methodology and techniques 82

8.3 Demographic and genetic objectives of captive breeding 92

8.4 Low reproductive success 93

8.5 Summary 98

9 Recovery actions: Reintroduction and translocation 100

9.1 Translocation on Santa Catalina 100

9.2 Reintroduction on Santa Catalina 102

9.3 Reintroduction program on the northern islands 103

9.4 Success of reintroduction 111

9.5 Summary 113

10 Reproductive biology Cheryl Asa 115

10.1 Reproductive cycles 116

10.2 Captive breeding 117

10.3 Results of the monitoring study 123

10.4 Summary 127

11 Diseases of island foxes Linda Munson 129

11.1 Disease in island populations 130

11.2 Could viral disease explain the population declines? 131

11.3 Do other viruses infect island foxes? 133

11.4 Do non-viral pathogens infect island foxes? 134

11.5 Parasites infecting island foxes 134

11.6 Non-infectious diseases in island foxes 138

11.7 Genetic diversity versus disease resistance 140

11.8 Disease as a cause of death 141

11.9 Overall health of the island fox populations 142

12 Zoos, education, and public participation 144

12.1 Public advocacy 144

12.2 The role of zoos 146

12.3 Tachi and Finnegan 149

12.4 Environmental education 152

12.5 Summary 152

13 Managing recovery: Cooperative conservation, politics, and the Endangered Species Act 154

13.1 Stakeholders and recovery 154

13.2 A model for management: the Island Fox Conservation Working Group 156

13.3 Listing the island fox as endangered 158

13.4 Changes in island fox management due to listing 159

13.5 The benefits and challenges of ESA listing 163

13.6 Conclusion 165

14 The ecological role of island foxes 167

14.1 Introduction 167

14.2 Background 167

14.3 Prey response 169

14.4 Competitors 174

14.5 Island communities without foxes 176

14.6 Implications for research and management 177

15 Conclusion 180

15.1 Status 180

15.2 Future 181

References 185

Index 207

Editorial Reviews

"This book provides the first comprehensive description of the evolution, genetics, diseases, reproductive biology, food habits and habitat use, and behavioral ecology of the island foxes. Most of the information presented was gained through actual recovery efforts. This work is a major contribution to literature on endangered species recovery, conservation biology, and mammalogy. Highly recommended."
R.L. Smith, emeritus, West Virginia University for Choice Magazine

"I found the book to be very interesting and inspiring."
Park Science

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