Invasive alien species: the urban dimension Case studies on strengthening local action in Europe Compiled by: Chantal van Ham, Piero Genovesi and Riccardo Scalera EuropEan union rEprEsEntativE officE Invasive alien species: the urban dimension Case studies on strengthening local action in Europe Invasive alien species: the urban dimension Case studies on strengthening local action in Europe Compiled by: Chantal van Ham, Piero Genovesi and Riccardo Scalera Invasive alien species: the urban dimension Case studies on strengthening local action in Europe The designation of geographical entities in this publication, and the presentation of the material, do not imply the expression of any opinion whatsoever on the part of IUCN. The views expressed in this publication do not necessarily reflect those of IUCN. This publication has been made possible with funding from the Swiss Government – Federal Office for the Environment and the Deutsche Bundesstiftung Umwelt. Published by: IUCN European Union Representative Office Copyright: © 2013 International Union for Conservation of Nature and Natural Resources Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale or other commercial purposes is prohibited without prior written permission of the copyright holder. Citation: van Ham, C., Genovesi, P., Scalera, R. (2013). Invasive alien species: the urban dimension, Case studies on strengthening local action in Europe. Brussels, Belgium: IUCN European Union Representative Office. 103pp. ISBN: 978-2-8317-1625-1 Design by: Imre Sebestyén Jr. / UNITgraphics.com Cover photo: Psittacula krameri © Riccardo Scalera Printed by: RPC Rosseels printing and communication (Belgium) Available from: IUCN European Union Representative Office Boulevard Louis Schmidt 64 1040 Brussels, Belgium [email protected] Tel +32 2 732 82 99 www.iucn.org/publications Contents Acknowledgements 6 ........................................................................................................................................................... Foreword 7 ............................................................................................................................................................................... Preface 8 ................................................................................................................................................................................... 1 Introduction 10 ..................................................................................................................................................................... 2 Case studies 14 ................................................................................................................................................................... 2.1 Austria 16 .................................................................................................................................................................... Management of the perennial invasive alien plant Giant goldenrod (Solidago gigantea) in the Greater Vienna area 16 ............................................................................................. 2.2 Belgium 19 .................................................................................................................................................................. American bullfrog (Lithobates catesbeianus) in Flanders 19 ............................................................................ Canada geese in Flanders urban areas 23 .......................................................................................................... Invasive plants and prevention in the green sector in Belgium 27 .................................................................. 2.3 Croatia 30 .................................................................................................................................................................... Diversity and distribution of invasive flora in Maksimir Park, Zagreb 30 ........................................................ Red-eared slider in Maksimir Park, Zagreb 32 .................................................................................................... 2.4 Czech Republic 34 ..................................................................................................................................................... Urban private gardens and spread of invasive plant species in the Czech Republic 34 ............................ 2.5 Estonia 37 ................................................................................................................................................................... Invasive hogweed species in Keila municipality, Harju county 37 ................................................................... 2.6 Finland 39 .................................................................................................................................................................... Establishment of feral rabbits in the city of Helsinki 39 ..................................................................................... 2.7 Germany 41 ................................................................................................................................................................ The unrestricted spread of North American raccoon in Berlin 41 ................................................................... 2.8 Greece 45 .................................................................................................................................................................... Invasion of Silverstripe blaasop in Rhodes Island, Greece 45 ......................................................................... 2.9 Ireland 50 ..................................................................................................................................................................... Invasive plant species in aquatic and riparian habitats in the urban Dublin area 50 ................................... Control of Hottentot Fig (Carpobrotus edulis) on Howth Head, Dublin 57 .................................................... 2.10 Israel 60 ....................................................................................................................................................................... Invasion of jellyfish in the coastal waters of Israel 60 ......................................................................................... 2.11 Italy 63 ......................................................................................................................................................................... Eradicating American Eastern grey squirrels in Genoa Nervi urban park 63 ................................................ Eastern grey squirrels in Perugia, Umbria 67 ...................................................................................................... 2.12 Netherlands 71 ........................................................................................................................................................... Pallas’s squirrels in the city of Weert 71 ............................................................................................................... 2.13 Portugal 73 .................................................................................................................................................................. Removal of invasive plant species in Vila Nova de Gaia 73 .............................................................................. 2.14 Switzerland 76 ............................................................................................................................................................ Fighting Common ragweed (Ambrosia artemisiifolia) and other invasive plant species in Geneva State 76 ................................................................................................................................................... 2.15 UK 79 ........................................................................................................................................................................... London Invasive Species Initiative – a case study 79 ........................................................................................ Monk Parakeet control in London 83 .................................................................................................................... Japanese knotweed (Fallopia japonica) in Swansea in the City and County of Swansea – a local authority perspective 86 ............................................................................................................................. New Zealand flatworms (Arthurdendyus triangulatu) in Scotland 90 .............................................................. 2.16 Europe and global 93 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . House crow (Corvus splendens) – an invasive bird travels to European cities 93 ....................................... Japanese knotweed and other exotic invasive knotweeds (Fallopia spp.) in Europe 98 ............................ 3 General information sources on invasive alien species 103 .................................................................................. 5 Invasive alien species: the urban dimension Case studies on strengthening local action in Europe Acknowledgements We would like to thank all contributors, reviewers We would like to thank the photographers for their and supporters of this publication. excellent work and willingness to share their photo material with us. This publication has benefited greatly from the expert advice and input provided by Piero Genovesi This publication was peer reviewed by the IUCN and Riccardo Scalera of the IUCN SSC Invasive Invasive Species Specialist Group and approved Species Specialist Group (IUCN SSC ISSG). by Luc Bas, Director of the IUCN European Union Representative Office. We would like to thank all the case study authors for providing their knowledge and expertise and We would also like to thank Liza Drius for highly appreciate their support in preparing the case proofreading the publication. studies for this publication: Antonella Pancucci- Papadopoulou, Bella S. Galil, Biljana Janev IUCN expresses gratitude for the financial support Hutinec, Brian Boag, Daniele Paoloni, Dave Parrott, provided by the Deutsche Bundesstiftung Umwelt Emanuelle Favre, Guntram Meier, Jan Pergl, Joe and the Swiss Federal Office for the Environment. Caffrey, Kadri Tilleman, Karen Harper, Katharina Lapin, Lana Jelić, Maryann Harris, Mathieu Halford, Mieke Hoogewijs, Noeleen Smyth, Nuno Gomes Oliveira, Petri Nummi, Raimo Pakarinen, Richard Shaw, Sandro Bertolino, Sean Hathaway, Sofie Standaert, Stefanos Kalogirou, Sven Jelaska, Urs Schaffner and Wiebe Lammers. 6 Invasive alien species: the urban dimension Foreword Invasive Alien Species (IAS) pose a significant threat The examples of local action presented in this to biodiversity in Europe, like elsewhere in the world. publication bring evidence of the threat which IAS This threat is likely to increase in the future unless pose to European cities and urban environments, meaningful action is taken at all levels to control the and provide solutions which can be adopted in an introduction and establishment of these species and attempt to combat biological invasions. Most of the address those already introduced. It is estimated that case studies compiled in this publication concern the economic impact of IAS only in the European actions undertaken at the local or regional levels; Union causes some 12.5 billion Euros worth of however it is important to highlight the international damage each year. nature of IAS. Only collaboration between countries in Europe, and worldwide, will allow addressing the Although the challenges posed by IAS are common movement of alien species and hence their invasive to many European countries, there is currently spread. no dedicated European legislation to address them. At the European Union level, the European With this publication, IUCN highlights the key role that Commission in its Biodiversity Strategy to 2020, European local authorities play in addressing the risks proposes filling this gap by developing a dedicated associated with biological invasions. IUCN aims to legislative instrument, which is due to be presented strengthen collaboration with all stakeholders in the in 2013. This instrument would tackle outstanding urban environment and offers its scientific knowledge challenges related to IAS pathways, early detection and expertise to support achieving the ambitious and response, containment and management of requirements of the future EU legislation. IAS. This is one of six key objectives of the EU 2020 Biodiversity Strategy adopted in May 2011: “By Luc Bas 2020, Invasive Alien Species and their pathways Director are identified and prioritised, priority species are European Union Representative Office controlled or eradicated, and pathways are managed IUCN to prevent the introduction and establishment of new IAS”. Local and regional authorities have an important role to play in implementing international, EU and national biodiversity targets and can greatly contribute to raising awareness about IAS among decision-makers and citizens. 7 Invasive alien species: the urban dimension Case studies on strengthening local action in Europe Preface are urban environments pivotal to understanding and managing biological invasions? By Riccardo Scalera and Piero Genovesi The story of a rabbit population deep burrowing is also due to the fact that a number of potential in a graveyard area, loosening the roots of trees, pathways, such as botanical gardens, zoos, making tombstones fall, and horrifying people, nurseries and private gardens, concentrate within may look like the plot of an old B horror movie. Yet, urban environments. In addition, urban areas are this is what the experts report about the situation privileged centres for some of the most prominent in Helsinki, where in 1985 rabbits established a pathways and vectors, including trade of pets feral population descended from pets dumped and ornamental plants etc. which can increase in the wild. Outside their natural range (the rabbit the propagule pressure that facilitates the invasion is native to the southern Iberian Peninsula), this processes. Not surprisingly, many studies have species is considered as a key driver of ecosystem demonstrated that cities are hotspots of invasions, change, as it can cause extensive erosion of soils particularly for plants. Human settlements are often by overgrazing and burrowing, which can cause the point of origin of many invasive species, which significant impact on the composition and local spread into adjacent landscapes along transport abundance of native wildlife. The most renowned corridors such as railways, waterways and roads, in case is that of Australia, where introduced rabbits many cases eventually invading natural areas. have devastated large areas of cropland. But also in Europe the impacts caused by this species can Furthermore, urban environments in many cases be very severe, also in terms of economic loss. host an important proportion of the overall For example, until now the estimated economic biodiversity, and as a result, invasive alien species impact of rabbits in Helsinki exceeds 2 million represent a serious threat to the native wildlife Euros. The damage caused by their introduction in urbanised areas, that are often already under has been known for thousands of years in Europe. “siege”. Generalist predators such as feral cats, for Pliny the Elder, an erudite natural philosopher and example, prey on a variety of native species living encyclopaedist of the early Roman Empire, wrote in in urban areas, which may suffer severe population his Natural History (77 AD) that the invasion of this declines. According to some estimates derived species in the Balearic Islands was such a severe from scaling up local studies to the national level, problem that the help of the late Emperor Augustus the about 9 million cats living in Great Britain, for and the Roman troops was sought to control them. example, killed 52–63 million mammals, 25–29 million birds and 4–6 million reptiles and amphibians The history of biological invasions in Europe dates during a 5-month survey period. However, the back to at least the Neolithic Age, especially in the management of cats, along with many other Mediterranean region. Many alien species have invasive alien species, particularly those kept as now become an integral part of our landscapes and pets, is often opposed by a large part of the public, cultures, which is the case for the Mediterranean and it is therefore crucial to improve our capacity to cypress in Tuscany or the pheasant in many areas explain the reasons behind any control program, to of Europe. Nevertheless, in the last centuries, and mitigate the conflicts that these interventions may particularly decades, the increasing movement of raise. In fact, the opposition is often a consequence people and goods across the globe has sharply of lack of awareness or misinformation regarding increased the opportunities of alien species to be the actual impact of such species. The situation introduced and become invasive. As shown by the is well exemplified by the case study of the Grey many contributions published in this report, the squirrel. This North American species, introduced to urban environment – often characterised by high Great Britain, Ireland and Italy on several occasions levels of disturbance, high intensity of transport, since the end of 19th century, outcompetes the and high environmental heterogeneity – has usually native red squirrel, has significant economic impact played a crucial role in biological invasions. This on agriculture and is also reported to be a garden 8