Jumping the Garden Fence Invasive garden plants in Australia and their environmental and agricultural impacts A CSIRO report for WWF-Australia by R.H. Groves CSIRO Plant Industry Robert Boden Robert Boden & Associates W.M. Lonsdale CSIRO Entomology February 2005 Jumping the Garden Fence: Invasive Garden Plants in Australia © WWF-Australia 2005. All Rights Reserved. ISBN 1 875941 84 3 Authors: Richard Groves, Robert Boden and Mark Lonsdale WWF-Australia Head Office Level 13, 235 Jones St Ultimo NSW 2007 Tel: +612 9281 5515 Fax: +612 9281 1060 www.wwf.org.au Published in February 2005 by WWF-Australia. Any reproduction in full or part of this publication must mention the title and credit the above mentioned publisher as the copyright owner. First published in February 2005 For bibliographic purposes this paper should be cited as: Groves, R.H., Boden, R. & Lonsdale, W.M. 2005. Jumping the Garden Fence: Invasive Garden Plants in Australia and their environmental and agricultural impacts. CSIRO report prepared for WWF-Australia. WWF-Australia, Sydney. The opinions expressed in this publication are those of the authors and do not necessarily reflect the view of WWF. For copies of this report, please contact WWF-Australia at [email protected] or call 1800 032 551. World Wide Fund for Nature ABN: 57 001 594 074 Acknowledgments. We thank Andreas Glanznig for initiating the project and commenting throughout the gestation of this report. Dave Albrecht (Alice Springs), George Batianoff (Qld), Kate Blood (Vic), Geoff Butler and Geoff Price (ACT), David Cooke (SA), John Hosking (NSW), Greg Keighery (WA), Andrew Mitchell (NT Top End) and Tim Rudman (Tas) gave their time and experience to nominate the most important garden plants that were still for sale in their respective jurisdictions. Rod Randall generously provided advice on his data base of naturalised invasive garden plants. Photographs were kindly provided by George Batianoff, Ralph Dowling, John Hosking, Greg Keighery, Tim Rudman, Geoff Sainty, Sally Vidler and Colin Wilson. Kate Blood, Greg Keighery and Dane Panetta commented on an early draft. The support of the Albert George and Nancy Caroline Youngman Trust as managed by Equity Trustees is gratefully acknowledged. WWF-Australia is part of the WWF International Network, the world’s largest and most experienced independent conservation organisation. It has close to five million supporters and a global network active more than 100 countries. WWF’s mission is to stop the degradation of the planet’s natural environment and to build a future in which humans live in harmony with nature, by: • conserving the world’s biological diversity; • ensuring that the use of renewable natural resources is sustainable; and • promoting the reduction of pollution and wasteful consumption. 2 WWF-Australia Jumping the Garden Fence: Invasive Garden Plants in Australia About the Authors Dr Richard Groves is a Senior Principal Research Scientist with CSIRO Plant Industry, Canberra. He has 40 years’ research experience on the ecology of plant invasions and in natural vegetation management. Since 1998, he has also been an Adjunct Professor in the Division of Botany & Zoology, ANU. Richard has undertaken research at universities and research centres in the US, South Africa, New Zealand, France and Japan. He has co-edited a number of books on biological invasions, weed biology and Australian vegetation. Other roles include: • Member, Australian Weeds Committee 1977-2000. • Member, SCOPE International Scientific Advisory Committee 1983-1987. • Chairman, CONCOM Working Group on Control of Weeds in National Parks, 1985-1992. • Program Leader, CRC Weed Management Systems, 1995-2002. • Task Leader, CRC Australian Weed Management, 2001-2004. Dr Robert Boden is a principal of Robert Boden & Associates and a former long standing Director of the Australian National Botanic Gardens in Canberra. He has extensive experience in natural resource management, which includes: • working at senior executive levels on natural resource management policy development in Commonwealth Government departments and agencies, and • leading Australian delegations to international conferences on endangered species, migratory birds and wetlands. As a consultant Robert has: • carried out policy reviews of Australian Government natural resource management programs • held ACT statutory positions of Chair, ACT Flora and Fauna Committee and Adviser, Tree Protection (Interim Scheme) Act 2001. Dr Mark Lonsdale Assistant Chief CSIRO Entomology Division Canberra and Chair of the Global Invasive Species Program Board. Mark has 20 years' experience in research into invasive species: • He organised the development process and wrote the business plan for the successful re-bid of the CRC for Australian Weed Management • He co-ordinated CSIRO's new research program on ecological implications of GMOs. • He is a member of the Board of the CRC for Pest Animal Control, 2003- He also has an international reputation in the area: • Member, Editorial Board, Biological Invasions 1998- • Member, SCOPE Global Invasive Species Program 1999-2001. • Member, Global Change in Terrestrial Ecosystems program 1999- WWF-Australia 3 Jumping the Garden Fence: Invasive Garden Plants in Australia Contents Executive summary 7 Chapter 1 – Introduction 11 Chapter 2 – Stages and pathways for invasion 12 Chapter 3 - Two hundred plus years of plant invasions in Australia 16 Chapter 4 – Negative impacts of invasive garden plants: 20 (a) impacts on Australian biodiversity (b) impacts on Australian agriculture Chapter 5 – The current situation concerning the availability for sale by 35 nurseries of invasive garden plants: (a) major weeds (b) in relation to Australian biodiversity (c) in relation to Australian agriculture Chapter 6 – Recommendations for better management of sale of invasive 72 garden plants Chapter 7 – Concluding discussion 74 References 75 Appendix 1. National list of invasive and potentially invasive garden plants 79 Appendix 2. Fact sheets for the most invasive garden plants in each 102 Australian State or Territory Boxes 1 Canberra’s hedges – a case study of ornamentals emerging as 20 weeds 2 Paterson’s Curse (Echium plantagineum) – a widespread naturalised 29 invasive garden plant causing major agricultural impacts 3 Lippia (Phyla canescens) – a major emerging naturalised invasive 30 garden plant causing serious agricultural impacts 4 Mexican feather grass (Nassella tenuissima) – a newly naturalised 31 invasive garden plant that has the potential to cause major agricultural impacts 5 Bear-skin fescue (Festuca gautieri) – a newly introduced invasive 32 garden plant that is a known grazing weed 6 Plantation trees gone wild 60 7 Native plants outside their natural range can also be invasive 61 4 WWF-Australia Jumping the Garden Fence: Invasive Garden Plants in Australia Figures 1 The stages of plant invasions with numbers of species 14 known for Australia for the different stages (based on data of R.P. Randall, pers. comm. & 2001; Virtue et al. 2002; Groves et al. 2003; DEH 2004; Virtue et al. 2004;). 2 (a) Number of naturalised plant species in the four Australian 17 States of Queensland, New South Wales, Victoria and South Australia 1870-1980 (Fig. 14 of Specht 1981); (b) Number of plant Taxa naturalising in Australia for each five-year period between 1971 and 1995 (Fig. 4 of Groves et al. 1998) 3 Means of introduction of those plant species naturalising in Australia 19 between 1971 and 1995 (Fig. 7 of Groves et al. 1998) 4 Rates of naturalisation of accidential, horticultural, and agricultural 19 plant introductions to urban Auckland for six periods of naturalisation (Fig.1 of Esler & Astridge 1987). Note the increasing proportion of deliberate horticultural introductions that have naturalised since 1940. 5 Numbers of Sand-hill greenhood (Pterosylis arenicolor) with and without 23 Bridal creeper (Asparagus asparagoides) at Tailem Bend, SA (from Sorensen & Jusaitis 1995). 6 Estimated distribution of lippia in the Condamine catchment 30 (from Julien et al. 2004) 7 Potential distribution of Nassella tenuissima predicted from a climate 31 profile of distributions in its countries of origin (from McLaren et al. 2004) 8 Potential distribution of Festuca gautieri as determined by ‘Climate’ 32 (from Spafford Jacob et al. 2004) Tables 1 Weed status by industry sector of exotic plant species introduced to 15 Australia, April 2004 2 The means of introduction of the naturalised species of South Australia 18 (from Kloot 1987) 3 The thirteen milestones on the road to extinction (after King 1987) 21 4 The numbers of presumed extinct and endangered plant species in 22 the Australian flora in relation to a variety of environmental threats (from Leigh & Briggs 1992). 5 Naturalised invasive and potentially invasive garden plants which are 36 noxious, prohibited from sale, both nationally and by jurisdiction 6 Summary of those commercially available naturalised invasive and potentially 37 invasive garden plants that are major weeds or impact on biodiversity and agriculture 7 The ten most serious invasive garden plants in Australia 40 currently available for sale by nurseries 8 The ten most serious invasive garden plants currently available 51 for sale in New South Wales 9 The ten most serious invasive garden plants currently available 52 for sale in Queensland 10 The ten most serious invasive garden plants currently available 53 for sale in South Australia 11 The ten most serious invasive garden plants currently available 54