Alien species in Norway – with the Norwegian Black List 2012 Alien species in Norway – with the Norwegian Black List 2012 presents an overview of ecological impact assessments of alien species which reproduce in Norwegian territories. The assessments are based upon a new and semi- quantitative set of criteria, where the species’ invasion potential and ecological effect are considered. The work has been carried out by 11 groups of experts who have treated ca. 2500 species. Impact assessments have been made for 1180 alien species which reproduce in Norwegian territories and for 134 species which might arrive in Norway with the aid of humans in the future – so called ‘door knockers’. A total of 106 species are categorised as having a severe impact, 111 species as having a high impact, 198 species as having a potentially high impact, 399 species as having a low impact, and 366 species as having no known impact in Norwegian nature. In addition, species inform- ation has been gathered for 1071 alien species which do not reproduce on the Norwegian mainland and territorial waters, and 69 non-reproducing alien species observed in Svalbard. Distribution: Norwegian Biodiversity Information Centre 7491 Trondheim Alien species in Norway Phone: +47 73592145 e-mail: [email protected] –with the Norwegian Black List www.biodiversity.no 2012 Alien species in Norway –with the Norwegian Black List 2012 Editors Lisbeth Gederaas, Toril Loennechen Moen, Sigrun Skjelseth, Line-Kristin Larsen Project management Lisbeth Gederaas Groups of experts See chapter “The work of the expert groups” Database development and management Stein Arild Hoem, Helge Sandmark Layout Skipnes Kommunikasjon AS, Åshild Viken (front cover) Cover Harmonia axyridis Cover photo Bjørn H. Stuedal and Geir Mogen Internet adaption Helge Sandmark, Askild Olsen, Skjalg Woldstad English translation: Paul Shimmings Recommended citation Gederaas, L., Moen, T.L., Skjelseth, S. & Larsen, L.-K. (eds.). Alien species in Norway – with the Norwegian Black List 2012. The Norwegian Biodiversity Information Centre, Norway. Chapter recommended citation Sandvik, H. 2012. Methods and set of criteria. Pp. 57-64 in: Gederaas, L., Moen, T.L., Skjelseth, S. & Larsen, L.-K. (eds.). Alien species in Norway – with the Norwegian Black List 2012. The Norwegian Biodiversity Information Centre, Norway. Distributed by The Norwegian Biodiversity Information Centre (NBIC), 7491 Trondheim, Norway. Phone: (+47) 73 59 21 45. E-mail: [email protected] Copies 300 Print Skipnes Kommunikasjon AS ISBN-13: 978-82-92838-38-9. Preface The spread of alien species is considered one of the It must be emphasised that the Norwegian greatest global threats to biodiversity. Norwegian Biodiversity Information Centre does not play society as a whole has become increasingly aware any role in the management of alien species, of alien species and their effects. Alien species may and thus does not consider whether or not an be responsible for considerable damage to native alien species should be allowed in Norway. species and habitats, and may have ecological This is an issue that must be decided by the impacts. The spread and establishment of alien appropriate authorities. species have also resulted in significant negative economic consequences around the world, Since the Norwegian Biodiversity Information along with posing threats to human health and Centre presented the first version of the agricultural species. Norwegian Black List in 2007, considerable progress has been made in developing the The role of the Norwegian Biodiversity methods we use to assess the ecological impacts Information Centre is defined in our mandate, posed by alien species in Norway. Our method “The Norwegian Biodiversity Information Centre is based on quantitative criteria, which is a is responsible for assessing the ecological impacts considerable improvement over the purely associated with species that are non-native to qualitative method we used in 2007. Norway (alien species) and to provide an overview of alien species found in Norway.” Given the global scope of alien species, the need for further development of methodology Alien species in Norway – with the Norwegian is still great. We need an international Black List 2012 thus focuses exclusively on process to develop a method that can assessments of ecological impact, and does not be used across national boundaries. The consider other negative consequences that may Centre for Conservation Biology (CCB) at result from non-native invasive species. Tables the Norwegian University of Science and provide an overview of the 2320 alien species Technology (NTNU), which helped develop that are found in Norway. Our mandate also our methodology in conjunction with a directs us to limit our ecological risk assessment selection of other experts, has helped put to species non-native to Norway. Norway in a good position to aid in a further Harmonia axyridis Photo: Bjørn H. Stuedal and Geir Mogen 3 Preface Alien species in Norway – with the Norwegian Black List 2012 development of methodology internationally. We The Norwegian Biodiversity Information Centre hopes think that Norwegian authorities should advocate this that Alien species in Norway – with the Norwegian Black view in relevant international forums. List 2012 can both serve as management tool as well as a source of information on alien species for relevant Another important issue is the lack of information authorities and the public. on alien species. This lack is the biggest limitation on our use of quantitative methods. If Norway intends to Finally, we would like to thank the experts who have been continue to develop and expand its assessments of the involved in the method development, impact assessments ecological impact posed by alien species, Norwegian and writing of this document. These experts have made authorities must increase their efforts to strengthen our an invaluable contribution that has resulted in important knowledge base. new information and assessments of alien species. Trondheim 12th June 2012 Ivar Myklebust Director, Norwegian Biodiversity Information Centre 4 Contents Preface .................................................... 3 Why do some species become a problem? ..... 41 The effects of alien species ............................. 43 Contents .................................................. 5 Structural changes in habitat ..................... 43 Influence on native species ........................ 48 Summary ................................................. 7 Genetic effects – introgression ................... 51 Vectors for diseases and parasites ............ 52 Introduction ............................................. 9 Climate change and alien species .................... 54 New methods and new set of criteria ........ 10 Acknowledgements ......................................... 56 Collation of information ............................. 10 Availability of data ...................................... 11 Methods and set of criteria ..................... 57 Definitions and delimitations ............................ 11 Invasion axis ..................................................... 58 What is an alien species? .......................... 11 Effect axis ......................................................... 61 Time delimitations ...................................... 12 Impact categories ............................................. 62 Geographical delimitations ......................... 12 Documentation .................................................. 63 ‘Door knockers’ ......................................... 12 Uncertainty ....................................................... 63 Alien species classified into four groups .... 14 Species not included in the assessments .. 14 The work of the expert groups ................... 65 Extent of existing knowledge ..................... 16 Selection of species ......................................... 65 What is the Black List? ..................................... 16 ‘Door knockers’ ......................................... 67 Species which do not reproduce in Norway 67 Alien species: introduction, Species which are excluded ..................... 67 establishment and spread ....................... 17 Taxonomy, names and localised information . 67 Native or alien species? ................................... 21 Species – and subspecies ......................... 67 Where do alien species come from? ............... 23 Areas ........................................................... 67 How do alien species get to Norway? .............. 26 Comprehensive information Intentional introduction .............................. 26 available on the internet ............................. 67 Unintentional introduction ......................... 33 Localised information ................................. 68 Secondary spread of alien species Vascular plants and adaptation of methodology 68 from neighbouring areas ............................ 35 State of knowledge – a challenge .................... 68 What happens when species arrive The groups of experts’ assessment in new environments? ....................................... 35 of background knowledge ............................... 69 Establishment and adaptation ................... 37 Expert group on algae ................................ 69 Spread ........................................................ 40 Expert group on fungi ................................ 70 Colpomenia peregrina Photo: Vivian Husa 5 Contents