UNIVERSITY OF CALIFORNIA SANTA CRUZ THREATENED INSULAR VERTEBRATES: A GLOBAL ASSESSMENT OF ISLANDS, THREATS AND CONSERVATION OPPORTUNITIES A dissertation submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in ECOLOGY AND EVOLUTIONARY BIOLOGY by Dena R. Spatz December 2016 The Dissertation of Dena R. Spatz is approved: _____________________________ Professor Donald A. Croll, Chair _____________________________ Professor Ingrid M. Parker _____________________________ Professor Peter T. Raimondi _____________________________ Professor Daniel Simberloff _____________________________ Nick D. Holmes, Ph.D __________________________ Tyrus Miller, Vice Provost and Dean of Graduate Studies Copyright © by Dena R. Spatz 2016 Table of Contents List of Tables ................................................................................................................ v List of Figures ............................................................................................................. vii List of Appendices ....................................................................................................... ix Abstract ......................................................................................................................... x Acknowledgements ..................................................................................................... xii Introduction ................................................................................................................... 1 Chapter 1. Globally threatened vertebrates on islands with invasive species ............... 8 Abstract ............................................................................................................................... 8 Introduction ........................................................................................................................ 8 Methods ............................................................................................................................. 11 Threatened Vertebrates on Islands ................................................................................................11 Island Biogeography .....................................................................................................................12 People and Invasive Vertebrates on Islands ..................................................................................13 Results ................................................................................................................................ 15 Highly Threatened Vertebrates on Islands ....................................................................................15 Breeding Populations ....................................................................................................................16 Extirpations (Population Extinctions) ...........................................................................................17 People and Invasive Vertebrates on Islands ..................................................................................17 Discussion .......................................................................................................................... 19 Biogeographic patterns in highly threatened vertebrate species ...................................................19 Managing invasive vertebrates on islands ....................................................................................21 Knowledge gaps and moving forward ..........................................................................................23 Conclusions...................................................................................................................................24 Tables ................................................................................................................................. 27 Figures ............................................................................................................................... 33 Chapter 2. Globally Threatened Seabirds and Conservation Opportunities on Islands ..................................................................................................................................... 38 Abstract ............................................................................................................................. 38 Introduction ...................................................................................................................... 38 Methods ............................................................................................................................. 40 Identifying Species and Islands ....................................................................................................41 Identifying Threatened Seabird Islands with and without Invasive Species and Legal Protection ......................................................................................................................................................42 Identifying Threatened Seabird Islands with Opportunities for Conservation ..............................44 Results ................................................................................................................................ 45 Globally Threatened Seabird Distribution ....................................................................................45 Threatened Seabird Island Attributes ............................................................................................45 Invasive Species and Lack of Legal Protection on Threatened Seabird Islands ...........................46 iii Conservation Opportunities ..........................................................................................................48 Discussion .......................................................................................................................... 48 Tables ................................................................................................................................. 53 Figures ............................................................................................................................... 56 Chapter 3. Managing Invasive Mammals on Islands to Conserve Globally Threatened Seabirds in a Changing Climate .................................................................................. 63 Abstract ............................................................................................................................. 63 Introduction ...................................................................................................................... 63 Methods ............................................................................................................................. 65 Islands ...........................................................................................................................................65 Identifying islands for their conservation importance to seabirds ................................................66 Island Conservation Management Portfolios ................................................................................68 Results ................................................................................................................................ 71 Seabird and Island Scores .............................................................................................................71 Coastal Flooding Risk ...................................................................................................................72 Conservation Management Portfolios ...........................................................................................72 Discussion .......................................................................................................................... 74 Management Portfolios .................................................................................................................75 Conclusions...................................................................................................................................78 Tables ................................................................................................................................. 80 Figures ............................................................................................................................... 86 Synthesis ..................................................................................................................... 89 Appendices .................................................................................................................. 94 Bibliography ............................................................................................................. 101 iv List of Tables Table 1.1. Current and historic breeding status’ assigned to each threatened terrestrial vertebrate population on an island. ............................................................................. 27 Table 1.2. Island status category definitions describing the presence or absence of invasive vertebrates on each island and the status applied to each invasive on each island ........................................................................................................................... 28 Table 1.3. The number and percent of each invasive vertebrate group on islands with highly threatened vertebrate taxa ...............................................................................