A review of impact assessment protocols of non-native plants

  • Montserrat Vilà
  • Belinda Gallardo
  • Cristina Preda
  • Emili García-Berthou
  • Franz Essl
  • Marc Kenis
  • Helen E. Roy
  • Pablo González-Moreno


Impact assessment protocols (i.e. scoring systems) for non-native species have been developed and implemented relatively recently, driven by an increasing demand for desk study approaches to screen and classify non-native species, considering their environmental and socio-economic impacts. While a number of impact assessment protocols have been developed, there are no clear guidelines to help researchers, environmental practitioners and policy-makers understand their differences, uses and limitations, and to ultimately assist in the choice of protocol and practical implementation. In this review, we compare the main structure of 26 impact assessment protocols used for non-native plants. We describe these protocols in terms of the impact types that they include, the way in which impacts are categorized and ranked, how uncertainty is considered, and how the overall score is calculated. In general, environmental impacts are included more often than socio-economic impacts. Impacts are rated by estimates of the intensity, extent, persistence and reversibility of the impact. Uncertainty is mainly estimated by the availability and quality of the scientific information, but also by the agreement and relevance of the available evidence on impacts beyond the region in which the impact is assessed (including the assessment of climatic similarity with other invaded areas). The final impact score is usually calculated as the sum of scores, the maximum score achieved across all impact types, or a rule-based aggregation of impacts in order to provide a final rank of the non-native species. We finally indicate issues related with transparency, redundancy, clarity, friendliness, scope, scaling, reproducibility and flexibility as key challenges for impact assessment improvement.


Decision-making Environmental impacts Risk analysis Scoring system Socio-economic impacts Uncertainty 



We thank S. Kumschick and two anonymous reviewers for comments to a previous version of the manuscript. This publication is based upon work from COST Action TD1209 “Alien Challenge” ( supported by the European Cooperation in Science and Technology (COST). The content of this manuscript is the authors’ responsibility and neither COST nor any person acting on its behalf is responsible for the use, which might be made of the information contained in it. The study was partially supported by the project IMPLANTIN (CGL2015-65346-R) of the Spanish Ministerio de Economía y Competitividad (MINECO). MK and PG-M were supported by CABI with core financial support from its member countries (see for details).

Supplementary material

10530_2018_1872_MOESM1_ESM.xlsx (20 kb)
Supplementary material 1 (XLSX 20 kb)


  1. Andersen MC, Adams H, Hope B, Powell M (2004) Risk assessment for invasive species. Risk Anal 24:787–793. CrossRefPubMedGoogle Scholar
  2. Andreu J, Manzano-Piedras E, Bartomeus I, Dana ED, Vilà M (2010) Vegetation response after removal of the invasive Carpobrotus hybrid complex in Andalucía, Spain. Ecol Restor 28:440–448CrossRefGoogle Scholar
  3. Bacher S, Blackburn TM, Essl F et al (2018) Socio-economic impact classification of alien taxa (SEICAT). Methods Ecol Evol 9:159–168. CrossRefGoogle Scholar
  4. Baker RHA, Black R, Copp GH et al (2008) The UK risk assessment scheme for all non-native species. In: Rabitsch W, Essl F, Klingenstein F (eds.) Biological invasions—from ecology to conservation. Neobiota 7:46–57Google Scholar
  5. Barney JN, Tekiela DR, Dollete ESJ, Tomasek BJ (2013) What is the “real” impact of invasive plant species? Front Ecol Environ 11:322–329. CrossRefGoogle Scholar
  6. Benke KK, Steel JL, Weiss JE (2011) Risk assessment models for invasive species: uncertainty in rankings from multi-criteria analysis. Biol Invasions 13:239–253CrossRefGoogle Scholar
  7. Blackburn TM, Essl F, Evans T et al (2014) A unified classification of alien species based on the magnitude of their environmental impacts. PLoS Biol 12:e1001850. CrossRefPubMedPubMedCentralGoogle Scholar
  8. Branquart E, Verreycken H, Vanderhoeven S, Van Rossum F, Cigar J (2009) ISEIA, a Belgian non-native species assessment protocol. Science facing aliens. Belgian Biodiversity Platform, Brussels, pp 11–17Google Scholar
  9. Brunel S, Blanquart E, Fried G et al (2010) The EPPO prioritization process for invasive alien plants. EPPO Bull 40:407–422. CrossRefGoogle Scholar
  10. Burgiel SW, Perrault AM (2011) Black, white, and gray lists. In: Rejmánek M, Simberloff D (eds) Encyclopedia of biological invasions. University of California Press, Berkeley, pp 75–77Google Scholar
  11. Carboneras C, Genovesi P, Vilà M et al (2018) A prioritised list of invasive alien species to assist the effective implementation of EU legislation. J Appl Ecol 55:539–547CrossRefGoogle Scholar
  12. D’hondt B, Vanderhoeven S, Roelandt S et al (2015) Harmonia + and Pandora +: risk screening tools for potentially invasive plants, animals and their pathogens. Biol Invasions 17:1869–1883. CrossRefGoogle Scholar
  13. EFSA (2011) Guidance on the environmental risk assessment of plant pests. EFSA J 9(12):2460. CrossRefGoogle Scholar
  14. Essl F, Nehring S, Klingenstein F et al (2011) Review of risk assessment systems of IAS in Europe and introducing the German-Austrian black list information system (GABLIS). J Nat Conserv 19:339–350. CrossRefGoogle Scholar
  15. Essl F, Nehring S, Klingenstein F et al (2017) Scientific and normative foundations for the valuation of alien-species impacts: thirteen core principles. Bioscience 67:166–178. CrossRefGoogle Scholar
  16. Faulkner KT, Robertson MP, Rouget M, Wilson JRU (2014) A simple, rapid methodology for developing invasive species watch lists. Biol Conserv 179:25–32. CrossRefGoogle Scholar
  17. Gallardo B, Aldridge DC (2013) Priority setting for invasive species management: risk assessment of Ponto-Caspian invasive species into Great Britain. Ecol Appl 23:352–364CrossRefGoogle Scholar
  18. Gallardo B, Zieritz A, Adriens T et al (2016) Trans-national horizon scanning for invasive non-native species: a case study in Western Europe. Biol Invasions 18:17–30. CrossRefGoogle Scholar
  19. Garry Oak Ecosystems Recovery Team (2007) General decision process for managing invasive plant species in Garry Oak and associated ecosystems (GOEs). Accessed 6 Nov 2018
  20. Gilioli G, Schrader G, Carlsson N et al (2017) Environmental risk assessment for invasive alien species: a case study of apple snails affecting ecosystem services in Europe. Environ Impact Assess Rev 65:1–11CrossRefGoogle Scholar
  21. Gordon DR, Onderdonk DA, Fox AM, Stocker RK (2008) Consistent accuracy of the Australian weed risk assessment system across varied geographies. Divers Distrib 14:234–242CrossRefGoogle Scholar
  22. Hagen BL, Kumschick S (2018) The relevance of using various scoring schemes revealed by an impact assessment of feral mammals. Neobiota 8:37–75Google Scholar
  23. Hawkins CL, Bacher S, Essl E et al (2015) Framework and guidelines for implementing the proposed IUCN environmental impact classification for alien taxa (EICAT). Divers Distrib 21:1360–1363. CrossRefGoogle Scholar
  24. Heikkilä J (2011) A review of risk prioritization schemes of pathogens, pests and weeds: principles and practices. Agric Food Science 20:15–28CrossRefGoogle Scholar
  25. Hiebert RD, Stubbendieck JL (1993) Handbook for ranking exotic plants for management and control. Natural resources Report NPS/NRMWRO/NRR-93/08. US Department of the Interior, National Park Service, Natural Resources Publication Office, Denver, ColoradoGoogle Scholar
  26. Holt J, Leach A, Knight J et al (2012) Tools for visualizing and integrating pest risk assessment ratings and uncertainties. EPPO Bull 42:35–41. CrossRefGoogle Scholar
  27. Hulme PE, Pyšek P, Jarošík V et al (2013) Bias and error in understanding plant invasion impacts. Trends Ecol Evol 28:212–218. CrossRefPubMedGoogle Scholar
  28. Jeschke JM, Bacher S, Blackburn TM et al (2014) Defining the impact of non-native species. Conserv Biol 28:1188–1194. CrossRefPubMedPubMedCentralGoogle Scholar
  29. Johnson S (2009) NSW weed risk management system. Industry and Investment NSW, OrangeGoogle Scholar
  30. Kenis M, Bacher S, Baker RMA et al (2012) New protocols to assess the environmental impact of pests in the EPPO decision-support scheme for pest risk analysis. EPPO Bull 42:21–27. CrossRefGoogle Scholar
  31. Koop AL, Fowler L, Newton LP, Caton BP (2012) Development and validation of a weed screening tool for the United States. Biol Invasions 14:273–294. CrossRefGoogle Scholar
  32. Kumschick S, Bacher S, Gaertner M et al (2015) Ecological impacts of alien species: quantification, scope, caveats, and recommendations. Bioscience 65:55–63. CrossRefGoogle Scholar
  33. Leung B, Roura-Pascual N, Bacher S et al (2012) TEASIng apart alien species risk assessments: a framework for best practices. Ecol Lett 15:1475–1493. CrossRefPubMedGoogle Scholar
  34. Lodge DM, Simonin PW, Burgiel SW et al (2016) Risk analysis and bioeconomics of invasive species to inform policy and management. Ann Re Environ Resour 41:453–488. CrossRefGoogle Scholar
  35. Mastrandrea MD, Field CB, Stocker TF et al (2011) The IPCC AR5 guidance note on consistent treatment of uncertainties: a common approach across the working groups. Clim Change 108:675. CrossRefGoogle Scholar
  36. Miller TK, Allen CR, Landis WG, Merchant JW (2010) Risk assessment: simultaneously prioritizing the control of invasive plant species and the conservation of rare plant species. Biol Conserv 143:2070–2079. CrossRefGoogle Scholar
  37. Morse LE, Randall JM, Benton N et al (2004) An invasive species assessment protocol: Evaluating non-native plants for their impact on biodiversity, Version 1. NatureServe, Arlington, VirginiaGoogle Scholar
  38. Mumford J, Booy O, Baker RMA et al (2010) Invasive non-native species risk assessment in Great Britain. Aspects Appl Biol 104:49–54Google Scholar
  39. Nentwig W, Bacher S, Pyšek P et al (2016) The generic impact scoring system (GISS): a standardized tool to quantify the impacts of alien species. Environ Monit Assess 188:315. CrossRefPubMedGoogle Scholar
  40. Nentwig W, Mebs D, Vilà M (2017) Impact of non-native animals and plants on human health. In: Vilà M, Hulme PE (eds) Impact of biological invasions on ecosystem services. Springer International Publishing, Berlin, pp 277–293CrossRefGoogle Scholar
  41. Nentwig W, Bacher S, Kumschick S et al (2018) More than “100 worst” alien species in Europe. Biol Invas 20:1611–1621CrossRefGoogle Scholar
  42. Olenin S, Didžiulis V (2009) Introduction to the list of alien taxa. In: DAISIE (ed) Handbook of alien species of Europe. Springer, Berlin, pp 129–236CrossRefGoogle Scholar
  43. Orr R (2003) Generic nonindigenous aquatic organisms risk analysis review process. In: Ruiz GM, Carlton JT (eds) Invasive species: vectors and management strategies. Island Press, Washington, DC, pp 415–438Google Scholar
  44. Ou J, Lu C, O’Toole DK (2008) A risk assessment system for alien plant bio-invasion in Xiamen, China. J Environ Sci 20:989–997CrossRefGoogle Scholar
  45. Parker IM, Simberloff D, Lonsdale WM et al (1999) Impact: toward a framework for understanding the ecological effects of invaders. Biol Invasions 1:3–19. CrossRefGoogle Scholar
  46. Parker C, Caton BP, Fowler L (2007) Ranking nonindigenous weed species by their potential to invade the United States. Weed Sci 55:386–397. CrossRefGoogle Scholar
  47. Pheloung PC, Williams PA, Halloy SR (1999) A weed risk assessment model for use as a biosecurity tool evaluating plant introductions. J Environ Manage 57:239–251. CrossRefGoogle Scholar
  48. Pyšek P, Jarošík V, Hulme PE et al (2012) A global assessment of invasive plant impacts on resident species, communities and ecosystems: the interaction of impact measures, invading species’ traits and environment. Glob Chang Biol 18:1725–1737. CrossRefPubMedCentralGoogle Scholar
  49. Rabitsch W, Essl F, Schindler S (2017) The rise of non-native vectors and reservoirs of human diseases. In: Vilà M, Hulme PE (eds) Impact of Biological Invasions on Ecosystem Services. Springer International Publishing, Berlin, pp 263–275CrossRefGoogle Scholar
  50. Randall JM, Larry E, Morse LE et al (2008) The invasive species assessment protocol: a tool for creating regional and national lists of invasive nonnative plants that negatively impact biodiversity. Invasive Plant Sci Manag 1:36–49CrossRefGoogle Scholar
  51. Ricciardi A, Hoopes MF, Marchetti MP, Lockwood JL (2013) Progress toward understanding the ecological impacts of nonnative species. Ecol Monogr 83:263–282. CrossRefGoogle Scholar
  52. Roy HE, Peyton J, Aldridge DC et al (2014) Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain. Global Change Biol 20:3859–3871. CrossRefGoogle Scholar
  53. Roy EH, Rabitch W, Scalera R et al (2017) Developing a framework of minimum standards for the risk assessment of alien species. J Appl Ecol. CrossRefGoogle Scholar
  54. Rumlerová Z, Vilà M, Pergl J et al (2016) Scoring environmental and socioeconomic impacts of alien plants invasive in Europe. Biol Invasions 18:3697–3711. CrossRefGoogle Scholar
  55. Sandvik H, Sæther BE, Holmern T et al (2013) Generic ecological impact assessments of alien species in Norway: a semi-quantitative set of criteria. Biodivers Conserv 22:37–62. CrossRefGoogle Scholar
  56. Seebens H, Blackburn TM, Dyer EE et al (2017) No saturation in the accumulation of alien species worldwide. Nat Commun 8:14435. CrossRefPubMedPubMedCentralGoogle Scholar
  57. Simberloff D, Alexander M (1998) Assessing risks to ecological systems from biological introductions (excluding genetically modified organisms). In: Calow P (ed) Handbook of environmental risk assessment and management. Blackwell, Oxford, pp 147–175Google Scholar
  58. Turbé A, Strubbe D, Mori E et al (2017) Assessing the assessments: evaluation of four impact assessment protocols for invasive alien species. Divers Distrib 23:297–307CrossRefGoogle Scholar
  59. van Kleunen M, Dawson W, Essl F et al (2015) Global exchange and accumulation of non-native plants. Nature 525:100. CrossRefPubMedGoogle Scholar
  60. Vanderhoeven S, Branquart E, Casaer J et al (2017) Beyond protocols: improving the reliability of expert-based risk analysis underpinning invasive species policies. Biol Invasions 19:2507–2517. CrossRefGoogle Scholar
  61. Vaz AS, Castro-Diez P, Godoy O et al (2018) An indicator-based approach to analyse the effects of non-native tree species on multiple cultural ecosystem services. Ecol Indic 85:48–56. CrossRefGoogle Scholar
  62. Vilà M, Hulme PE (2017a) Impact of biological invasions on ecosystem services. Springer International Publishing, BerlinCrossRefGoogle Scholar
  63. Vilà M, Hulme PE (2017b) Non-native species, ecosystem services and human well-being. In: Vilà M, Hulme PE (eds) Impact of biological invasions on ecosystem services. Springer, HeidelbergCrossRefGoogle Scholar
  64. Vilà M, Tessier M, Suehs CM et al (2006) Local and regional assessments of the impacts of plant invaders on vegetation structure and soil properties of Mediterranean islands. J Biogeogr 33:853–861. CrossRefGoogle Scholar
  65. Vilà M, Basnou C, Pyšek P et al (2010) How well do we understand the impacts of alien species on ecosystem services? A pan-European, cross-taxa assessment. Front Ecol Environ 8:135–144. CrossRefGoogle Scholar
  66. Vilà M, Espinar J, Hejda M et al (2011) Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems. Ecol Lett 14:702–708. CrossRefPubMedGoogle Scholar
  67. Walther GR, Roques A, Hulme PE et al (2009) Alien species in a warmer world: risks and opportunities. Trends Ecol Evol 24:686–693. CrossRefPubMedGoogle Scholar
  68. Warner PJ, Bossard CC, Brooks ML et al (2003) Criteria for categorizing invasive non-native plants that threaten wildlands. California Exotic Pest Plant Council and Southwest Vegetation Management Association. and Accessed 6 Nov 2018
  69. Yelenik SG, D’Antonio CM (2013) Self-reinforcing impacts of plant invasions change over time. Nature 503:517–520. CrossRefPubMedGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  1. 1.Estación Biológica de Doñana (EBD-CSIC)SevilleSpain
  2. 2.Applied and Restoration Ecology GroupPyrenean Institute of Ecology (IPE-CSIC)SaragossaSpain
  3. 3.Ovidius University of Constanta, Al. UniversitatiiConstantaRomania
  4. 4.GRECO, Institute of Aquatic Ecology, University of GironaGironaSpain
  5. 5.Division of Conservation Biology, Vegetation and Landscape EcologyUniversity ViennaViennaAustria
  6. 6.CABIDelémontSwitzerland
  7. 7.Centre for Ecology & HydrologyCrowmarsh GiffordUK
  8. 8.CABIEghamUK

Personalised recommendations