International Union for Conservation of Nature (IUCN) Red List of Threatened Species
Species are classified in 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) – No known individuals remaining.
- A species becomes extinct when the last existing member dies. Extinction therefore becomes a certainty when there are no surviving individuals that are able to reproduce and create a new generation. A species may become functionally extinct when only a handful of individuals survive, which cannot reproduce due to poor health, age, sparse distribution over a large range, a lack of individuals of both sexes (in sexually reproducing species), or other reasons
- Extinct in the Wild (EW) – Known only to survive in captivity, or as a naturalized population outside its historic range.
Extinct in the Wild (EW) 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) – Extremely high risk of extinction in the wild.
Critically Endangered is the highest risk category assigned by the IUCN Red List for wild species. Critically Endangered means that a species is either facing an extremely high risk of extinction, its numbers have decreased, or will decrease, by 80% within three generations.[1]
- Endangered (EN) – High risk of extinction in the wild.
An endangered species is a population of organisms which is facing a high risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters
- Vulnerable (VU) – High risk of endangerment in the wild.
A Vulnerable species is one which has been categorised by the International Union for Conservation of Nature (IUCN) as likely to become Endangered unless the circumstances threatening its survival and reproduction improve.
- Near Threatened (NT) – Likely to become endangered in the near future.
Near Threatened (NT) is a conservation statusassigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status
- Least Concern (LC) – Lowest risk. Does not qualify for a more at risk category. Widespread and abundant taxa are included in this category.
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. As such they do not qualify as threatened, Near Threatened, or (prior to 2001) Conservation Dependent.
- Data Deficient (DD) – Not enough data to make an assessment of its risk of extinction.
Data Deficient (DD) is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment ofconservation status to be made.
- Not Evaluated (NE) – Has not yet been evaluated against the criteria
Not Evaluated (NE) is a category applied by the IUCN, other agencies, and individuals to a species when they haven't been studied by the IUCN Red List of Threatened Species[1]
