C OODED E OOFF CCONDUCTO N D U C T OONN HHORTICULTUREO R T I C U L T U R E AANDN D IINVASIVEN V A S I V E AALIENL I E N PPLANTSL A N T S . 162 O N - PLANTS ALIEN Many of the plants used in agriculture, horticulture and forestry in Europe are not native to the continent. A small percentage of these plants, introduced on purpose, escape the framework of cultivation, become naturalised and invade natural, semi-natural or artifi cial ecosystems. INVASIVE Others are introduced accidentally and may also end up in nature. These invasive alien plants may have signifi cant ecological and economic AND consequences or become harmful to human health. This code of conduct, a result of the collaboration between the Council of Europe and the European and Mediterranean Plant Protection Organization, is aimed at increasing co-operation among all the actors involved in horticulture, in both the public and private sectors, for the HORTICULTURE prevention of new invasions of alien plants in Europe. ON ISBN 978-92-871-7037-8 CONDUCT OF ODE 9 789287 170378 C www.coe.int/Biodiversity CCodeode ddee cconduiteonduite GGBB CCouverture.inddouverture.indd 1 003/05/113/05/11 116:076:07 C ODE OF CONDUCT ON HORTICULTURE AND INVASIVE ALIEN PLANTS French edition: Code de conduite sur l’horticulture et les plantes exotiques envahissantes ISBN : 978-92-871-7035-4 For a full list of titles in this series, please see the back of the book. The opinions expressed in this work are those of the authors and do not necessarily refl ect the offi cial policy of the Directorate of Culture and Cul- tural and Natural Heritage. All rights reserved. No part of this publication may be translated, re- produced or transmitted in any form or by any means, electronic (CD- Rom, Internet, etc.) or mechanical, including photocopying, recording or any information storage or retrieval system, without prior permission in writing from the Public Information and Publications Division, Direc- torate of Communication (F-67075 Strasbourg Cedex or publishing@ coe.int). Cover design: Ott-imprimeurs Publications Production: Ott-imprimeurs Cover image: Franck Billeton Council of Europe Publishing F-67075 Strasbourg www.coe.int/Biodiversity ISBN : 978-92-871-7037-8 © Council of Europe, May 2011 Printed at Ott-imprimeurs - Wasselonne, France C ODE OF CONDUCT ON HORTICULTURE AND INVASIVE ALIEN PLANTS Vernon Heywood and Sarah Brunel Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Nature and environment, no. 162 Code of conduct on horticulture and invasive alien plants C OONTENTSN T E N T S Presentation ................................................................................ 7 Introduction ................................................................................. 9 1. Characteristics of horticultural invasive alien plants ............. 10 2. Pathways of introduction of invasive alien plants ......................... 11 3. Environmental and economic impacts ...................................... 14 4. Botanic gardens and invasive species ...................................... 16 5. Existing initiatives .............................................................................. 17 6. The Code of Conduct – a voluntary instrument ..................... 22 The Code of Conduct ................................................................. 25 Audience and aims .............................................................................. 25 Be aware of which species are invasive in your area ................. 25 Know exactly what you are growing: ensure that material introduced into cultivation is correctly identifi ed ................... 26 Be aware of regulations concerning invasive alien plants...... 28 Work in co-operation with other stakeholders, both in the trade and the conservation and plant protection sectors ............................................................................ 37 Agree which plant species are a threat and cease to stock them or make them available ............................................... 37 Avoid using invasive or potentially alien plants in large-scale public planting .................................................................................. 39 Adopt good labelling practices ....................................................... 39 Make substitutes for invasives available ....................................... 41 Be careful how you get rid of plant waste and dispose of unwanted stock of plants and plant-containing waste ....... 42 Adopt good production practices to avoid unintentional introduction and spread ................................................................ 44 Engage in publicity and outreach activities ................................. 48 Code of conduct on horticulture and invasive alien plants Take into account the increased risks of alien plant invasions due to global change .............................................................................. 50 References ................................................................................... 53 Appendices ................................................................................. 61 Appendix 1: Defi nitions ...................................................................... 61 Appendix 2: Examples of existing initiatives ............................... 65 Appendix 3: St Louis Voluntary Codes of Conduct .................... 69 Appendix 4: Recommendations proposed to lessen the overall impact of invasive plant species deliberately introduced for horticulture and currently available for sale .... 71 Appendix 5: List of species considered invasive in the Euro-Mediterranean region ......................................................... 73 Appendix 6: Examples of proposals of alternative plants for the south of France ................................................................... 75 Titles available in the various series ........................................ 79 6 T his code of conduct was prepared by Vernon Heywood and Sarah Brunel as a joint collaboration of the Council of Eu- rope (CoE) and the European and Mediterranean Plant Protec- tion Organization (EPPO). On the basis of this document, EPPO is developing “Guidelines on the development of a code of con- duct on horticulture and invasive alien plants” that are directed to national plant protection organisations. We are grateful to the many organisations and individuals that have generously provided us with comments or suggestions, in particular the EPPO Panel on Invasive Alien Species, Francis Brot, Keith Davenport, Franz Essl, Swen Follak, Helia Marchante, Madeleine McMullen, Françoise Petter and Richard Shaw. We have endeavoured to take these comments into account as far as possible. 7 Introduction I NNTRODUCTIONT R O D U C T I O N Most invasive plants have been introduced for horticultural use by nurseries, botanical gardens, and individuals (Reichard and White, 2001) M any of the plants used in European agriculture, horticul- ture and forestry are not native to the continent but have been introduced deliberately or accidentally at various times over the past 2 000 years from different parts of the world as a conse- quence of human activity. A distinction is often made in Europe between archaeophytes and neophytes – plants introduced be- fore or after 1492/1500 respectively (cf. Webb, 1985; Elorza et al. 2004). The European economy depends to a large extent on the cultivation of such alien plants. Most of these introductions have been benefi cial to humans and have not caused prob- lems through their becoming weedy or invasive. However, a small percentage of these introductions escape from cultiva- tion, become naturalised and invade natural, semi-natural or human-made ecosystems. They are known as invasive alien plants (IAPs) and may have signifi cant ecological or economic consequences or become harmful to human health. Their po- tential to alter ecosystem structure and function drastically has been widely recognised in recent years (cf. Levine et al. 2003). Globally, invasive alien species are widely acknowledged (for example, by the Convention on Biological Diversity and the Millennium Ecosystem Assessment) as one of the major threats to biodiversity, second only to habitat loss and degradation. In South Africa, alien plant species are considered the single big- gest threat to the country’s biological biodiver- sity1 and now cover more than 10.1 million hec- tares, threatening indigenous plants. They cause 1. www.dwaf.gov.za/wfw/. billions of South African rands of damage to the country’s economy every year. A comprehensive overview of invasive species in natural areas is provided by Weber’s Inva- sive plant species of the world. A reference guide to environmental 9 Code of conduct on horticulture and invasive alien plants 2 2. Weber, E, Invasive plant species of the world: A weeds. It covers 450 species that affect reference guide to environmental weeds. CABI Pub- natural habitats in various parts of the lishing, Wallingford, UK (2003). world. The terminology applied to invasive plants can be very confus- ing and there is little consistency of usage of the various terms applied. For details see Appendix 1. 1. Characteristics of horticultural invasive alien plants It is exceedingly diffi cult to determine which biological charac- teristics are good indicators of invasiveness, but although there are no generally applicable characteristics that apply to plants that become invasive in horticulture, they often share some of the following features: