To allow the underlying data to be analysed, and to ensure uniformity when describing the habitat in which a taxon occurs, the threats to a taxon, what conservation actions are in place or are needed, and whether or not the taxon is utilized, a set of standard terms (Classification Schemes) have been developed for documenting taxa on The IUCN Red List.
The Classification Schemes for Threats and Conservation Actions Needed underwent a major review as part of a joint initiative between the IUCN Red List Partnership and The Conservation Measures Partnership, and are now in use (for further details about the schemes, click here). For an explanation of the Threats and Conservation Actions Needed Classification Schemes, please read the Conservation Biology 2008 article: A Standard Lexicon for Biodiversity Conservation: Unified Classifications of Threats and Actions.
The Classification Schemes used in IUCN Red List assessments include:
- Threats – to record past, ongoing and future threats to a taxon. For definitions, examples and guidance on the Threats Classification Scheme ver. 3.3, click here.
- Stresses – to record how each threat impacts a taxon. For definitions, examples and guidance on the Stresses Classification Scheme ver. 1.1, click here.
- Habitats – to record which habitats a taxon occurs in. For definitions, examples and guidance on the Habitats Classification Scheme ver. 3.1, click here.
- Conservation Actions In Place – to record what conservation actions are already in place for a taxon. For definitions, examples and guidance on the Conservation Actions in Place Classification Scheme ver 2.0, see here.
- Conservation Actions Needed – to record what conservation actions are needed for a taxon. For definitions, examples and guidance on the Conservation Actions Needed Classification Scheme ver. 2.0, click here.
- Research Needed – to record what further research is needed on a taxon. For definitions, examples and guidance on the Research Needed Classification Scheme ver. 1.0, click here.
- General Use and Trade – to record how a taxon is utilised and what level of trade occurs for the taxon. For the General Use and Trade Classification Scheme (including the Non-Consumptive Use scheme) ver. 1.0, click here.
- Livelihoods – to record the importance of a taxon to human livelihoods. For the Livelihoods Classification Scheme ver. 2.0, click here).
- Plant and Fungal Growth Forms – to record growth or life form to enable searches on the Red List web site for particular functional groups of plants (trees, shrubs, succulents, ferns, etc.) and fungi. For definitions and guidance on the Plant and Fungal Growth Forms Classification Scheme ver. 1.1, click here.
The guidance documents attached above to each Classification Scheme are working drafts and that whilst the Classification Schemes themselves may not change, the definitions, examples and guidance on use will be periodically updated, and new versions are indicated by the version number.
Prior to Red List version 2022-2, individual threats were assigned threat impact scores based on their timing, scope, and severity, and these scores were reported in the Threats section of each assessment. In consideration of the underdeveloped scientific basis for these scores, IUCN has temporarily stopped providing them beginning with Red List version 2022-2 while the technical basis for assigning threats and calculating threat impact scores is under review. However, these scores may still appear on pdf versions of legacy assessments that were completed previously. Users interested in these scores can generate them using this scoring table. Although assigning numerical scores to threats is difficult due to inconsistency in how threats are determined and uncertainty around how threats interact, among other challenges, threats marked with timing as “ongoing”, severity as “rapid” or “very rapid” declines and scopes of “majority” or “whole” are typically considered major threats to a species.