FINAL REPORT OF THE CHRISTMAS ISLAND EXPERT WORKING GROUP TO THE MINISTER FOR ENVIRONMENT PROTECTION, HERITAGE AND THE ARTS Red crabs, Christmas Island – Photo by Max Orchard Expert Working Group members Associate Professor Bob Beeton (Chair) Dr Andrew Burbidge Professor Gordon Grigg Professor Peter Harrison Dr Ric How Dr Bill Humphreys Mr Norm McKenzie Dr John Woinarski Secretariat Ms Anne-Marie Delahunt from February 2009 to October 2009 Ms Kerry Cameron from February 2009 to June 2009 Mr Harry Abrahams from October 2009 to March 2010 Ms Meryl Triggs from February 2009 to March 2010 1 April 2010 1 TABLE OF CONTENTS LIST OF FIGURES ......................................................................................................... 6 LIST OF TABLES........................................................................................................... 7 EXECUTIVE SUMMARY ................................................................................................ 8 Recommendations...................................................................................................... 12 1.0 INTRODUCTION..................................................................................................... 18 1.1 Initial Terms of Reference of the working group ............................................... 18 1.2 Amended Membership and Amended Terms of Reference .............................. 19 2.0 APPROACH TO ADDRESSING THE TERMS OF REFERENCE.......................... 19 2.1 Phase 1 .................................................................................................................. 19 2.2 Phase 2 .................................................................................................................. 21 3.0 CHRISTMAS ISLAND OVERVIEW ........................................................................ 21 3.1 Background information ...................................................................................... 21 3.1.1 Biophysical ....................................................................................................... 21 3.2 Social and Economic Matters .............................................................................. 23 3.2.1 Island Tenure and Governance........................................................................ 24 3.3 Biological............................................................................................................... 24 3.3.1 Introduction....................................................................................................... 24 3.3.2 Biodiversity Values ........................................................................................... 29 3.3.3 Ecological uniqueness and ecological shift ...................................................... 29 3.3.4 Biosecurity........................................................................................................ 32 4.0 SPECIFIC ISSUES CONSIDERED BY THE WORKING GROUP ......................... 34 4.1 Natural Dynamics of Oceanic Islands................................................................. 34 4.2 Securing Christmas Island against further invasions ....................................... 35 4.2.1 Governance and Quarantine ............................................................................ 35 4.3 Christmas Island research and monitoring ........................................................ 36 4.3.1 Scientific Research Priorities, Quality Assurance and Coordination ................ 37 4.3.2 Biodiversity Monitoring on Christmas Island..................................................... 38 4.4 Yellow Crazy Ant Management............................................................................ 40 2 4.5 General threats to endemic and other native species....................................... 41 4.5.1 Ecological shifts and associated cascade effects............................................. 41 4.5.2 Predation .......................................................................................................... 41 4.5.2.1 Cats (feral and domestic)........................................................................... 41 4.5.2.2 Rats ........................................................................................................... 42 4.5.2.3 Other introduced species........................................................................... 44 4.5.2.4 Potential Introductions ............................................................................... 44 4.5.3 Fipronil toxicity.................................................................................................. 45 4.5.4 Disease............................................................................................................. 45 4.5.5 Fire ................................................................................................................... 47 4.5.6 Land Clearance and Soil Removal................................................................... 47 4.5.7 Water................................................................................................................ 50 4.6 Conservation status of endemic species ........................................................... 51 4.7 Christmas Island Pipistrelle................................................................................. 51 4.8 Reptiles .................................................................................................................. 53 4.8.1 Introduction....................................................................................................... 53 4.8.2 Population Declines in Native Reptile Species................................................. 54 4.8.3 Likely causes of decline.................................................................................... 56 4.8.4 Conclusions...................................................................................................... 56 4.9 Conservation of Christmas Island birds ............................................................. 57 4.9.1 Introduction....................................................................................................... 57 4.9.2 Status, trends, threats and management priorities........................................... 58 4.10 Christmas Island Flying-Fox.............................................................................. 67 4.11 Christmas Island land crabs .............................................................................. 70 4.11.1 Red Crabs, Gecarcoidea natalis..................................................................... 70 4.11.2 Robber Crabs, Birgus latro............................................................................. 77 4.12 Flora and Vegetation........................................................................................... 80 4.12.1 Vegetation communities ................................................................................. 80 4.12.2 Weeds ............................................................................................................ 81 4.12.3 Native plant species of conservation concern ................................................ 81 4.12.4 Priorities for conservation of plants and vegetation communities................... 83 4.13 Other taxa ............................................................................................................ 84 4.14 Marine environment............................................................................................ 85 4.15 Subterranean Fauna ........................................................................................... 86 5.0 CONSIDERATION OF CHRISTMAS ISLAND AS A CONSERVATION ENTITY.. 87 5.1 Recognition of a unique place............................................................................. 87 5.2 Communicating Christmas Island’s Values ....................................................... 87 3 6.0 FINDINGS WITH WIDER APPLICABILITY............................................................ 87 7.0 ACKNOWLEDGEMENTS....................................................................................... 91 8.0 REFERENCES........................................................................................................ 92 9.0 GLOSSARY.......................................................................................................... 102 APPENDIX 1 CHRISTMAS ISLAND PIPISTRELLE.................................................. 104 4.7.1 Taxonomic Status........................................................................................... 104 4.7.2 Christmas Island Pipistrelle conservation status ............................................ 105 4.7.3 Christmas Island Pipistrelle biology................................................................ 106 4.7.4 Eco-physiology of Christmas Island Pipistrelle............................................... 107 4.7.5 Analysis of Christmas Island Pipistrelle Monitoring Data ............................... 108 4.7.6 Causes of Christmas Island Pipistrelle decline............................................... 114 4.7.6.1 Predation ................................................................................................. 114 4.7.6.2 Yellow Crazy Ants.................................................................................... 114 4.7.6.3 Wolf Snakes............................................................................................. 114 4.7.6.4 Rats and Cats .........................................................................................