Weed Categories for Natural and Agricultural Ecosystem Management R.H. Groves (Convenor), J.R. Hosking, G.N. Batianoff, D.A. Cooke, I.D. Cowie, R.W. Johnson, G.J. Keighery, B.J. Lepschi, A.A. Mitchell, M. Moerkerk, R.P. Randall, A.C. Rozefelds, N.G. Walsh and B.M. Waterhouse DEPARTMENT OF AGRICULTURE, FISHERIES AND FORESTRY Weed categories for natural and agricultural ecosystem management R.H. Groves1 (Convenor), J.R. Hosking2, G.N. Batianoff3, D.A. Cooke4, I.D. Cowie5, R.W. Johnson3, G.J. Keighery6, B.J. Lepschi7, A.A. Mitchell8, M. Moerkerk9, R.P. Randall10, A.C. Rozefelds11, N.G. Walsh12 and B.M. Waterhouse13 1 CSIRO Plant Industry & CRC for Australian Weed Management, GPO Box 1600, Canberra, ACT 2601 2 NSW Agriculture & CRC for Australian Weed Management, RMB 944, Tamworth, NSW 2340 3 Queensland Herbarium, Mt Coot-tha Road, Toowong, Qld 4066 4 Animal & Plant Control Commission, Department of Water, Land and Biodiversity Conservation, GPO Box 2834, Adelaide, SA 5001 5 NT Herbarium, Department of Primary Industries & Fisheries, GPO Box 990, Darwin, NT 0801 6 Department of Conservation & Land Management, PO Box 51, Wanneroo, WA 6065 7 Australian National Herbarium, GPO Box 1600, Canberra, ACT 2601 8 Northern Australia Quarantine Strategy, AQIS & CRC for Australian Weed Management, c/- NT Department of Primary Industries & Fisheries, GPO Box 3000, Darwin, NT 0801 9 Victorian Institute for Dryland Agriculture, NRE & CRC for Australian Weed Management, Private Bag 260, Horsham, Vic. 3401 10 Department of Agriculture Western Australia & CRC for Australian Weed Management, Locked Bag No. 4, Bentley, WA 6983 11 Tasmanian Museum and Art Gallery, GPO Box 1164, Hobart, Tas. 7001. 12 National Herbarium of Victoria, Royal Botanic Gardens, Birdwood Avenue, South Yarra, Vic. 3141 13 Northern Australia Quarantine Strategy, AQIS & CRC for Australian Weed Management, c/- Centre for Tropical Agriculture, PO Box 1054, Mareeba, Qld 4880 Weed Categories for Natural and Agricultural Ecosystem Management i © Commonwealth of Australia 2003 ISBN 0 642 47534 2 This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth available from the Department of Communications, Information Technology and the Arts. Requests and inquiries concerning reproduction and rights should be addressed to the Commonwealth Copyright Administration, Intellectual Property Branch, Department of Communications, Information Technology and the Arts, GPO Box 2154, Canberra ACT 2601 or at http://www.dcita.gov.au/cca. The Commonwealth of Australia acting through the Bureau of Rural Sciences has exercised due care and skill in the preparation and compilation of the information and data set out in this publication. Notwithstanding, the Bureau of Rural Sciences, its employees and advisers disclaim all liability, including liability for negligence, for any loss, damage, injury, expense or cost incurred by any person as a result of accessing, using or relying upon any of the information or data set out in this publication to the maximum extent permitted by law. Postal address: Bureau of Rural Sciences GPO Box 858 Canberra, ACT 2601 Copies available from: BRS Publication Sales GPO Box 858 Canberra ACT 2601 Ph: 1800 020 157 Fax: 02 6272 2330 Email: [email protected] Internet: http://www.affa.gov.au/brsweeds Preferred way to cite this publication: Groves, R.H. (Convenor), Hosking, J.R., Batianoff, G.N., Cooke, D.A., Cowie, I.D., Johnson, R.W., Keighery, G.J., Lepschi, B.J., Mitchell, A.A., Moerkerk, M., Randall, R.P., Rozefelds, A.C., Walsh N.G., and Waterhouse, B.M. (2003) Weed categories for natural and agricultural ecosystem management. Bureau of Rural Sciences, Canberra. Front cover photo credits (from left to right) Asystasia gangetica ssp. micrantha (Graham Prichard), Acacia catechu (Colin Wilson), Chromolaena odorata (Colin Wilson), Cyperus teneristolon (John Hosking). Back cover photo credits (from left to right) Chromolaena odorata (Colin Wilson), Acacia catechu (Colin Wilson), Onopordum tauricum (Richard Groves). ii Weed Categories for Natural and Agricultural Ecosystem Management FOREWORD Weeds are one of the major factors impacting on Australia’s biodiversity and agriculture. Weeds change the functioning of natural ecosystems, compete with and alter the habitat of native plants and animals and even threaten the survival of some species that are in low numbers. Weeds also impact negatively on agriculture by increasing costs either by interfering with crop growth or animal production or by acting as harbours for pests and diseases of agricultural plants. Introduced plants that have become naturalised in Australia now comprise about 10% of the total Australian flora. They include many plants that were introduced intentionally for agriculture and horticulture. Not all introduced and naturalised plants necessarily become invasive, although many do. This book aims to categorise the approximately 2700 non-native plant species that are known to be naturalised in Australia into groups of major or minor threats to natural ecosystems or agriculture. Some non- native naturalised plant species present in Australia are known to be weedy overseas and may have similar effects here. Some of these are recommended as targets for eradication programs because eradication could be achieved at relatively low cost before they become invasive and spread widely. The categories of non-native naturalised plants highlighted in this book thus suggest opportunities for future containment and eradication programs. This categorisation of Australia’s naturalised flora will be a useful resource for those involved in weed management, and those involved in natural resource management more broadly. Dr Peter O’Brien Dr Rhondda Dickson Executive Director First Assistant Secretary Bureau of Rural Sciences Department of the Environment and Heritage Land, Water and Coasts Division Weed Categories for Natural and Agricultural Ecosystem Management iii TABLE OF CONTENTS Foreword iii Summary 1 Introduction 2 Methods 4 Results 6 Discussion 11 Acknowledgments 14 Addendum 14 References 15 Appendix 1 16 Terms of reference from the Department of Environment and Heritage Appendix 2 17 Terms of reference from the Bureau or Rural Sciences Appendix 3 18 Naturalised non-native flora of Australia – natural ecosystems Appendix 4 106 Naturalised non-native flora of Australia – agricultural ecosystems iv Weed Categories for Natural and Agricultural Ecosystem Management SUMMARY The naturalised flora of Australia was compiled from vouchered specimens in State, Territory and national herbaria. It was found to consist of about 2700 species believed to be non-native, although some uncertainty remains about the introduced status of a small percentage of that total. Of this total, 798 species (about 30%) were considered a major problem and 1388 species (about 50%) a minor problem to managers of natural ecosystems. A total of 34 non-native species that are limited at present to one or a few populations in a defined geographic area is recommended for eradication from natural ecosystems. Those non-native species known to be having a direct impact on rare or threatened native plants numbered 49; most of these species are widely distributed across a number of States but 8 within this group with more limited distributions are suggested as further candidates for eradication from natural ecosystems. The majority (53%) of Australia’s naturalised non-native species were considered to pose little or no threat to agricultural ecosystems. Of the total of 1266 species that were considered a problem, 840 (about 65%) were categorised as a minor problem only, partly because they were not considered sufficiently important to warrant control at any location. Species that may act as harbours for diseases or insect pests, or that may be toxic at some stage of their life cycles, numbered 295. Sixteen naturalised non-native species were known to be subject currently to eradication attempts throughout their known Australian range because of their perceived impacts on agricultural ecosystems. A further 9 species are suggested as candidates for eradication from agricultural ecosystems. For nearly all the plant species considered, information on their dates of naturalisation, their likely rates of spread, or their likely economic impact was not available. These deficiencies in knowledge will need to be overcome before predictions of the probable negative impacts of weeds on Australian natural and agricultural ecosystems can be further refined. The work presented in this book was commissioned by the Department of Environment and Heritage and the Bureau of Rural Sciences in 2000 and 2001 respectively. The Cooperative Research Centre for Australian Weed Management convened a group of scientific experts on weeds and the Australian flora from all of the States and Territories of Australia to undertake the projects. This book represents a combination of the previously unpublished reports which resulted from these two projects. An addendum (page 14) briefly describes developments since the original reports were written. Weed Categories for Natural and Agricultural Ecosystem Management 1 INTRODUCTION A range of different categories and terms may be used to describe non-native plants, depending on what stage of the overall invasion process they are at, which in turn is determined largely by biological characteristics and introduction history. Naturalised