Revised Interim Report Christmas Island Expert Working Group to Minister for the Environment, 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 Dr Ric How Mr Norm McKenzie Dr John Woinarski Secretariat Ms Anne-Marie Delahunt Ms Kerry Cameron Ms Meryl Triggs 28 June 2009 1 Table of Contents TABLE OF CONTENTS.......................................................................................... 2 Introduction........................................................................................................................................ 5 What has happened on Christmas Island?..................................................................................... 6 Recommendations ............................................................................................................................ 7 Recommendations Level 1: Protecting the integrity of the island and better environmental governance ...................................................................................................................................... 10 Recommendations Level 2: Management of the island’s ecological processes so as to prevent further loss of biodiversity ............................................................................................... 10 Christmas Island Pipistrelle ........................................................................................................... 12 Tropicbirds..................................................................................................................................... 13 Highly Threatened Endemic Reptiles ............................................................................................ 13 Giant Centipedes and African Land Snails.................................................................................... 13 Scale Insect – Yellow Crazy Ant Nexus ........................................................................................ 13 Conserving Christmas Island as an Entity..................................................................................... 13 Communicating the Problem and Management Responses......................................................... 14 Findings with wider applicability .................................................................................................... 14 LIST OF FIGURES................................................................................................ 15 LIST OF TABLES ................................................................................................. 16 1.0 INTRODUCTION ............................................................................................. 17 1.1 Terms of Reference of the working group.............................................................................. 17 2.0 METHODOLOGY ............................................................................................ 17 3.0 CHRISTMAS ISLAND OVERVIEW................................................................. 20 3.1 Background information........................................................................................................... 20 3.1.1 Biophysical ........................................................................................................................... 20 3.2 Social Economic........................................................................................................................ 22 3.2.1 Island Tenure and Governance............................................................................................ 22 3.3 Biological ................................................................................................................................... 23 3.3.1 Introduction........................................................................................................................... 23 3.3.2 Biodiversity Values ............................................................................................................... 27 3.3.3 Ecological uniqueness and ecological shift.......................................................................... 27 3.3.4 Biosecurity (Background) ..................................................................................................... 29 2 4.0 SPECIFIC ISSUES CONSIDERED BY THE WORKING GROUP.................. 32 4.1 Natural Dynamics of Oceanic Islands..................................................................................... 32 4.2 Securing Christmas Island against further invasions........................................................... 32 4.2.1 Governance and Quarantine................................................................................................ 32 4.3 Christmas Island research and monitoring............................................................................ 33 4.3.1 Research Management........................................................................................................ 34 4.3.2 Biodiversity Monitoring on Christmas Island ........................................................................ 34 4.4 Yellow Crazy Ant Management................................................................................................ 36 4.5 General threats to endemic and other native species........................................................... 36 4.5.1 Ecological shift and associated cascade effects.................................................................. 36 4.5.2 Predation .............................................................................................................................. 37 4.5.2.1 Cats ............................................................................................................................... 37 4.5.2.2 Rats ............................................................................................................................... 37 4.5.2.3 Other introduced species .............................................................................................. 38 4.5.2.4 Potential Introductions................................................................................................... 38 4.5.3 Fipronil toxicity...................................................................................................................... 38 4.5.4 Disease ................................................................................................................................39 4.5.5 Fire ....................................................................................................................................... 40 4.5.6 Land Clearance.................................................................................................................... 41 4.5.7 Water use ............................................................................................................................. 41 4.6 Conservation status of endemic species ............................................................................... 41 4.7 Christmas Island Pipistrelle ..................................................................................................... 41 4.7.1 Taxonomic Status................................................................................................................. 41 4.7.2 Christmas Island Pipistrelle conservation status.................................................................. 42 4.7.3 Christmas Island Pipistrelle biology ..................................................................................... 43 4.7.4 Eco-physiology of Christmas Island Pipistrelle .................................................................... 44 4.7.5 Analysis of Christmas Island Pipistrelle Monitoring Data..................................................... 45 4.7.5 Causes of Christmas Island Pipistrelle decline .................................................................... 51 4.7.5.1 Predation....................................................................................................................... 51 4.7.5.2 Yellow Crazy Ants ......................................................................................................... 51 4.7.5.3 Wolf Snakes .................................................................................................................. 52 4.7.5.4 Rats and Cats................................................................................................................ 52 4.7.5.5 Nankeen Kestrels.......................................................................................................... 52 4.7.5.6 Giant Centipede ............................................................................................................ 52 4.7.5.7 Fipronil toxicity............................................................................................................... 54 4.7.5.8 Food availability and population changes in prey items ............................................... 54 4.7.5.9 Disease ......................................................................................................................... 55 4.7.5.10 Changes to surface water ........................................................................................... 56 4.7.5.11 Structural vegetation change ...................................................................................... 56 4.7.6 Working group’s conclusions on the Christmas Island Pipistrelle.......................................