The International Union for the Conservation of Nature and Natural Resources (IUCN) is one of the world's main authorities on the conservation status of the planet’s species and ecosystems.
The IUCN developed its ‘Red List of Threatened Species’ (also known as the IUCN Red List or Red Data List) in 1963, and it remains the world's most comprehensive inventory of the global conservation status of plants and animals.
The IUCN Red List is based upon precise scientific criteria to estimate the extinction risk of a given species or subspecies. These criteria are relevant to all species and all regions of the world. The aim of the list is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction.
Conservation Status
The conservation status of a species is an indicator of the likelihood of that species surviving into the future. Many factors are taken into account to assess the conservation status of a species; including the number remaining, the overall increase or decrease in the population over time, breeding success rates, known threats, and so on. The IUCN Red List is the best known conservation status list.
IUCN Red List Categories
Species are classified by the Red List into nine groups, set through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation.
- Extinct (EX)
Extinction is the cessation of existence of a species or group of taxa, which effectively reduces biodiversity. The moment of extinction is generally considered to be the death of the last individual of that species. - Extinct in the Wild (EW)
Extinct in the Wild is a conservation status assigned to species or lower taxa, the only known living members of which are being kept in captivity or as a naturalized population outside its historic range. - Critically endangered (CR)
Organisms with a conservation status of critically endangered (CR) have an extremely high risk of becoming extinct, and is the highest risk category assigned by the IUCN for wild species. CR means that a species numbers have decreased, or will decrease, by 80% within three generations - Endangered (EN)
An endangered species is a population of an organism which is at risk of becoming extinct in the very near future because it is either few in numbers, or threatened by changing environmental or predation parameters. - Vulnerable (VU)
A vulnerable species is a species which is likely to become endangered in the near future unless the circumstances threatening its survival and reproduction improve. - Near Threatened (NT)
Near Threatened (NT) is a conservation status assigned to species or lower taxa which may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status. As such, the IUCN notes the importance of re-evaluating Near Threatened taxa often or at appropriate intervals. - Least Concern (LC)
Least Concern (LC) is an IUCN category assigned to extant species or lower taxa which have been evaluated but do not qualify for any other category. Species cannot be assigned as LC unless they have had their population status evaluated, i.e. adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status. - Data Deficient (DD)
Data Deficient (DD) is a category applied by the IUCN to a species when the available information is not sufficient for a proper assessment of conservation status to be made. This does not necessarily mean that the species has not been extensively studied; but it does indicate that little or no information is available on the abundance and distribution of the species. - Not Evaluated (NE)
A taxon is Not Evaluated (NE) when it is has not yet been evaluated against the criteria.
