Using the IUCN Environmental Impact Classification for Alien Taxa to inform decision-making

© 2023 The Authors. Conservation Biology published by Wiley Periodicals LLC on behalf of Society for Conservation Biology. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The Environmental Impact Classification for Alien Taxa (EICAT) is an important tool for biological invasion policy and management and has been adopted as an International Union for Conservation of Nature (IUCN) standard to measure the severity of environmental impacts caused by organisms living outside their native ranges. EICAT has already been incorporated into some national and local decision-making procedures, making it a particularly relevant resource for addressing the impact of non-native species. Recently, some of the underlying conceptual principles of EICAT, particularly those related to the use of the precautionary approach, have been challenged. Although still relatively new, guidelines for the application and interpretation of EICAT will be periodically revisited by the IUCN community, based on scientific evidence, to improve the process. Some of the criticisms recently raised are based on subjectively selected assumptions that cannot be generalized and may harm global efforts to manage biological invasions. EICAT adopts a precautionary principle by considering a species’ impact history elsewhere because some taxa have traits that can make them inherently more harmful. Furthermore, non-native species are often important drivers of biodiversity loss even in the presence of other pressures. Ignoring the precautionary principle when tackling the impacts of non-native species has led to devastating consequences for human well-being, biodiversity, and ecosystems, as well as poor management outcomes, and thus to significant economic costs. EICAT is a relevant tool because it supports prioritization and management of non-native species and meeting and monitoring progress toward the Kunming–Montreal Global Biodiversity Framework (GBF) Target 6.

M.V. was supported by the Spanish Ministerio de Ciencia e Innovación project PREABROAD (EUR2022-134026) and RADIOPOPO (PID2021-122690OB-I00). S.B., M.V., B.G., J.M.J., and G.V. acknowledge funding by the Belmont Forum-BiodivERsA International joint call project InvasiBES and by the national funders Spanish Ministry of Science and Innovation (PCI 2018–092939 and PCI 2018–092986), Swiss National Science Foundation (31003A_179491 and 31BD30_184114), and German Federal Ministry of Education and Research (16LC1803A). G.B. and E.T. acknowledge the support of NBFC to the University of Florence and University of Sassari, funded by the Italian Ministry of University and Research, PNRR, Missione 4 Componente 2, ‘Dalla ricerca all'impressa’, Investimento 1.4, Project CN00000033. P.P. and A.N. were supported by EXPRO grant 19–28807X (Czech Science Foundation) and long-term research development project RVO 67985939 (Czech Academy of Sciences). M.G. was supported by the core research group Forest biology, Ecology, and Technology (P4-0107, Slovenian Research Agency) and by the Administration of the Republic of Slovenia for Food Safety, Veterinary Sector and Plant Protection (contracts C2337-22-000020 and C2337-23-000026). W.R. was supported by the project National Focal Point Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology(, Austria). H.E.R. was supported by the Natural Environment Research Council (NERC) award NE/R016429/1 under the UK-SCAPE program delivering National Capability.

Peer reviewed