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Policy support tool

Environmental Impact Classification of Alien Taxa (EICAT)

The IUCN Environmental Impact Classification of Alien Taxa (EICAT) is a simple, objective and transparent method for classifying alien taxa in terms of the magnitude of their detrimental environmental impacts in recipient areas. Alien taxa are classified into one of five ‘impact’ categories depending on the level of biological organisation (individual, population or community) impacted and the severity and reversibility of this impact, with the mechanisms by which the impacts occur aligned with those identified in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database ([GISD]; The EICAT adopts parallel classification systems to capture both the maximum impact ever recorded and the current impact level caused by the alien taxon.

Brochure: eicat_brochure_0.pdf

Aim of the resource

EICAT has the following five objectives (i) identify those taxa that have different levels of environmental impact, (ii) facilitate comparisons of the level of impact by alien taxa among regions and taxonomic groups, (iii) facilitate predictions of potential future impacts of taxa in the target region and elsewhere; (iv) aid in prioritisation of management actions, and (v) aid in evaluation of management methods. It is envisaged that the EICAT scheme will be used by scientists, land managers and conservation practitioners as a tool to gain a better understanding of the magnitude of impacts caused by different alien taxa, to alert relevant stakeholders to the possible consequences.

Requirements for using the resource NEW
  • Please see the Hawkins et al. 2015 publications provided below for the current version of the EICAT Categories and Criteria. 
  • The EICAT system has the potential to inform statutes adhering to relevant international agreements, including the Convention on Biological Diversity and its guidance on invasive alien species, WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement), and the Convention on International Trade in Endangered Species of Wild Fauna and Flora, to support the implementation of appropriate measures, and to inform risk assessments, but it does not replace them.

Potential limitations from using the resource
EICAT is not a risk assessment, and its output alone should not be used to assign the priority that should be attached to the control or management of any given alien species
while it is intended to be useful for ranking and prioritisation of management activities for established alien species within a country, the EICAT scheme should not be used alone to identify which alien species should be regulated
The output of the EICAT scheme is also not a statutory list of harmful invasive species
Scale of application
UN languages in which the resource is available
Development stage
Early access
Kevin Smith, Programme Officer, IUCN
Is the resource freely available?
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