Project Deliverance The response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria A Victorian Government Initiative Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria Department of Sustainability and Environment Project Deliverance The response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria A Victorian Government Initiative Publisher/Further information - Department of Sustainability and Environment, PO Box 500, East Melbourne, Victoria, Australia, 3002. Web: http://www.dse.vic.gov.au First published 2006. © The State of Victoria, Department of Sustainability and Environment, 2006 All rights reserved. This document is subject to the Copyright Act 1968. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form, or by any means, electronic, mechanical, photocopying or otherwise without the prior permission of the publisher. Copyright in photographs remains with the photographers mentioned in the text. ISBN 1 74152 343 5 Disclaimer—This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purpose and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Citation— Murray, A.J., Poore, R.N. and Dexter, N. (2006). Project Deliverance—the response of ‘critical weight range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria. Department of Sustainability and Environment, Melbourne. Front cover photographs—Long-nosed Potoroo, DSE/McCann; Forest at Cape Conran, Andrew Murray. Other photographs—p1 Long-nosed Potoroo, DSE/McCann; p3 Aerial view Cape Conran, DSE Orbost; p5 Banksia Woodland, Andrew Murray; p12 Bait station, Andrew Murray; p18 Red Fox, Dave Watts; p25 Long-nosed Potoroo, DSE/McCann; p39 Bandicoot tracks at Cape Conran, Martin O’Brien; p43 Banksia Woodland at Cape Conran, Andrew Murray. www.dse.vic.gov.au ii Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria Acknowledgments The authors wish to acknowledge that this study was carried out on land traditionally owned and managed by the Gunnai-Kurnai people and the Bidawal people of far East Gippsland. The authors would like to thank the following people and organisations for their valuable contribution and support: Brendan Edgar, formerly of the Environment Forest Taskforce within Environment Australia, for securing the funds for the first three years of the project. Rod Gowans, Ian Mansergh, Gordon Friend and Tim Clancy (Biodiversity Research Steering Committee) are thanked for ensuring that funds were made available to ensure the project could be satisfactorily concluded. Dr. Stephen Henry (Department of Sustainability & Environment, Orbost) for his unfailing support for this study, and his editorial corrections to the final draft of this report. Stephen Platt and Lawrence Ferns made invaluable editorial comments to the report. ‘Honey’ (Bob) Andrews was involved in the early stages of the project and helped make most of the bait stations. The numerous DSE and DPI colleagues involved in fire management, pest management and timber harvesting who were asked to modify, cease or otherwise put on hold some of their activities are acknowledged and thanked. We wish to thank Animal Control Technologies for mixing the beads and glitter into the free-feed baits. The local residents, who adjoined some of the study sites, in particular Mick Camilleri and Peter Wermke, are thanked for their interest in the project. Dr David Choquenot (formerly of the Arthur Rylah Institute for Environmental Research) provided support and encouragement. Barbara Triggs analysed scat samples, and numerous people assisted from time to time with the trapping program. Josh Puglisi, Manager of the Cape Conran cabins, has given us assistance and constant encouragement. Parks Victoria staff are thanked for their support, occasional use of equipment, and access to certain tracks. The forbearance of Larissa Murray while Andrew was based in Mallacoota trapping in the Stony Peak study site (and many other trips away) is greatly appreciated. Thanks to Dr Roger Pech, CSIRO Sustainable Ecosystems, Canberra ACT; Dr Glen Saunders, NSW Dept of Primary Industries, Vertebrate Pest Research Unit, Orange NSW; and Dr Graham Mitchell, Foursight Associates, and DSE Chief Scientist for reviewing the manuscript. Funding for this publication was provided by the Weeds and Pests on Public Land Including National Parks Initiative. Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria iii Contents Acknowledgments iii Table of Contents iv Summary 1 Section 1: Introduction 3 Objectives 3 Report structure 4 Known benefits of fox baiting 4 Developing a fox baiting strategy suitable for Victoria 4 Section 2: The Study Sites 5 Selection of paired baiting areas 5 The West Coast study site 6 The East Coast study site 8 The Stony Peak study site 9 Previous CWR mammal and fox surveys 11 Section 3: Baiting Strategy Design 12 Methods 13 Establishing bait stations 13 Baiting with non-toxic baits impregnated with indicator beads/glitter 14 Scat analysis 15 Results 15 Discussion 16 Area of effect and distance between bait stations 16 Untested variables 16 Conclusions 17 Section 4: Implementation of Poison Baiting 18 Methods 18 Results 19 West Coast study site 19 East Coast study site 19 Stony Peak study site 19 iv Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria Discussion 23 West Coast study site 23 East Coast study site 23 Stony Peak study site 23 Increase in bait-take over time 23 Bait-take as an indicator of success 24 Conclusions 24 Section 5: Monitoring the Response of Medium-sized Mammals 25 Critical Weight Range mammals 25 Species and their conservation status 26 Rate of increase in mammal populations 26 Methods 27 Design 27 Cage-trapping 27 Analysis of data 27 Rainfall 27 Results 28 Individual population response 28 Analysis of results 34 Rainfall data 37 Section 6: Discussion and Conclusions 39 Comparison to other studies 39 Responders – Long-nosed Potoroo & Southern Brown Bandicoot 39 Mixed response – Long-nosed Bandicoot 40 Mixed response – Common Brushtail Possum 41 Insignificant response – Common Ringtail Possum 41 Overall variability and habitat 41 Site variability 41 Conclusions 42 Appendix 1: Habitat complexity as a determinant of mammal populations 43 References 47 Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria v List of Figures Figure 1: Location of study sites 6 Figure 2: Layout of the West Coast study site, indicating the locations of the bait stations and the trapping transect in the treatment area and non-treatment area 7 Figure 3: Layout of the East Coast study site, indicating the locations of bait stations and the trapping transect in the treatment area and non-treatment area 8 Figure 4: Layout of the Stony Peak study site, indicating the locations of the bait stations and the trapping transect in the treatment area and non-treatment area 10 Figure 5: Diagrammatic cross-sectional view of a bait station as used in this study 14 Figure 6: The distance travelled from the bait station of presumed origin to the point of deposition 16 Figure 7: Bait-take in the West Coast non-treatment area 20 Figure 8: Bait-take in the West Coast treatment area 20 Figure 9: Bait-take in the East Coast non-treatment area 21 Figure 10: Bait-take in the East Coast treatment area 21 Figure 11: Bait-take in the Stony Peak non-treatment area 22 Figure 12: Bait-take in the Stony Peak treatment area 22 Figure 13: Trap success of all CWR species in the West Coast study site expressed as a percentage 30 Figure 14: Trap success of all CWR species in the East Coast study site expressed as a percentage 30 Figure 15: Trap success of all CWR species in the Stony Peak study site expressed as a percentage 31 Figure 16: Total captures per trap night (CPT-1) for Southern Brown Bandicoot 31 Figure 17: Total captures per trap night for Long-nosed Bandicoot 32 Figure 18: Total captures per trap night for Long-nosed Potoroo 32 Figure 19: Total captures per trap night for Common Brushtail Possum 33 Figure 20: Total captures per trap night for Common Ringtail Possum 33 Figure 21: Total captures per trap night for all mammals 33 Figure 22: Long-nosed Potoroos known-to-be-alive in the East Coast study site 34 Figure 23: Rainfall anomalies for Victoria from the 1st of April 1999 until the 31st of March 2002 37 Figure 24: Habitat Complexity Scores for trap sites located in the West Coast study site 45 Figure 25: Habitat Complexity Scores for trap sites located in the East Coast study site 45 Figure 26: Habitat Complexity Scores for trap sites located in the Stony Peak study site 46 vi Project Deliverance: the response of ‘critical-weight-range’ mammals to effective fox control in mesic forest habitats in far East Gippsland, Victoria