Biodiversity and Conservation

, Volume 22, Issue 1, pp 37–62 | Cite as

Generic ecological impact assessments of alien species in Norway: a semi-quantitative set of criteria

  • Hanno Sandvik
  • Bernt-Erik Sæther
  • Tomas Holmern
  • Jarle Tufto
  • Steinar Engen
  • Helen E. Roy
Original Paper


The ecological impact assessment scheme that has been developed to classify alien species in Norway is presented. The underlying set of criteria enables a generic and semi-quantitative impact assessment of alien species. The criteria produce a classification of alien species that is testable, transparent and easily adjustable to novel evidence or environmental change. This gives a high scientific and political legitimacy to the end product and enables an effective prioritization of management efforts, while at the same time paying attention to the precautionary principle. The criteria chosen are applicable to all species regardless of taxonomic position. This makes the assessment scheme comparable to the Red List criteria used to classify threatened species. The impact of alien species is expressed along two independent axes, one measuring invasion potential, the other ecological effects. Using this two-dimensional approach, the categorization captures the ecological impact of alien species, which is the product rather than the sum of spread and effect. Invasion potential is assessed using three criteria, including expected population lifetime and expansion rate. Ecological effects are evaluated using six criteria, including interactions with native species, changes in landscape types, and the potential to transmit genes or parasites. Effects on threatened species or landscape types receive greater weightings.


Black List criteria Ecological effect Invasion potential Non-native species Quantitative risk assessment Risk classification 



The development of the new set of criteria was solicited and funded by The Norwegian Biodiversity Information Centre (Artsdatabanken). Further funding was provided by the Norwegian Directorate for Nature Management (DN). Valuable input, comments and help came from L. Gederaas, S. Henriksen, T.L. Moen, I. Salvesen, H. Sandmark, S. Skjelseth (Artsdatabanken), E. Ødegaard (DN), H.H. Grundt (FlowerPower), M. Crawley (Imperial College), H. Loeng (Institute of Marine Research), R. Andersen (Museum of Natural History and Archaeology at NTNU), R. Elven (Natural History Museum at University of Oslo), L.T. Kristjánsson (Norwegian Directorate of Fisheries), H.P. Brække (Norwegian Food Safety Authority), B.H. Øyen (Norwegian Forest and Landscape Institute), T. Hofsvang (Norwegian Institute for Agricultural and Environmental Research), J.A. Kålås, F. Ødegaard, O.T. Sandlund, O. Skarpaas (Norwegian Institute for Nature Research), R.A. Ims (University of Tromsø) and the anonymous reviewers. We thank N. Straw at Forest Research (UK) for kindly providing observational data.


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Copyright information

© Springer Science+Business Media Dordrecht 2012

Authors and Affiliations

  • Hanno Sandvik
    • 1
  • Bernt-Erik Sæther
    • 1
  • Tomas Holmern
    • 1
    • 2
  • Jarle Tufto
    • 3
  • Steinar Engen
    • 3
  • Helen E. Roy
    • 4
  1. 1.Centre for Conservation Biology, Department of BiologyNorwegian University of Science and TechnologyTrondheimNorway
  2. 2.Norwegian Directorate for Nature ManagementTrondheimNorway
  3. 3.Centre for Conservation Biology, Department of Mathematical SciencesNorwegian University of Science and TechnologyTrondheimNorway
  4. 4.Biological Records CentreNERC Centre for Ecology & HydrologyWallingfordUK

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