Threatened species
conservation category for species categorized as rare, very rare, or depleted
A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of critical depensation, a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment without direct reference to human activity.
IUCN definition
The International Union for Conservation of Nature (IUCN) is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened:
Vulnerable species
Endangered species
Critically endangered species
Less-than-threatened categories are near threatened, least concern, and the no longer assigned category of conservation dependent. Species that have not been evaluated (NE), or do not have sufficient data (data deficient) also are not considered "threatened" by the IUCN.
Although threatened and vulnerable may be used interchangeably when discussing IUCN categories, the term threatened is generally used to refer to the three categories (critically endangered, endangered, and vulnerable), while vulnerable is used to refer to the least at risk of those three categories. They may be used interchangeably in most contexts however, as all vulnerable species are threatened species (vulnerable is a category of threatened species); and, as the more at-risk categories of threatened species (namely endangered and critically endangered) must, by definition, also qualify as vulnerable species, all threatened species may also be considered vulnerable.
Threatened species are also referred to as a red-listed species, as they are listed in the IUCN Red List of Threatened Species.
Subspecies, populations and stocks may also be classified as threatened.
By country
Australia
Federal
The Commonwealth of Australia (federal government) has legislation for categorising and protecting endangered species, namely the Environment Protection and Biodiversity Conservation Act 1999, which is known in short as the EPBC Act. This Act has six categories: extinct, extinct in the wild, critically endangered, endangered, vulnerable, and conservation dependent, as defined in Section 179 of the Act.
Begin with the source’s own compact description: “Threatened species” is conservation category for species categorized as rare, very rare, or depleted. The dossier treats that line as a proposition to test through Threatened, species and conservation, not as a finished interpretation.
Why this record matters
The phrase “conservation category for species categorized as rare, very rare, or depleted” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Sep 22, 2026. The linked authority identifier is Q16197023. The Library of Congress control number is sh85043044. None of the 1 selected statements returned an explicit reference. The first chronological checks are 1999.
Scientific names, classifications and consensus can change while older terminology persists in catalogues and historical literature. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Threatened species”, its source revision and the description used here.
- Expand the search: follow Threatened species primary sources, Threatened species archive and Threatened research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Threatened species”?
- Which observation, specimen, dataset or publication supports the account?
- Is the terminology current, historical or disputed?
Search terms from this dossier
This entry incorporates text from “Threatened species” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.