IUCN Red List

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The IUCN Red List of Threatened Species
IUCN Red List.svg
HeadquartersUnited Kingdom
Region served
Official language
Parent organization
International Union for Conservation of Nature
Affiliations Species Survival Commission, Birdlife International, Conservation International, NatureServe, Botanic Gardens Conservation International, Royal Botanic Gardens, Texas A&M University, Sapienza University of Rome, Zoological Society of London, Wildscreen
Website www.iucnredlist.org

The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), founded in 1965, has evolved to become the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red List are produced by countries or organizations, which assess the risk of extinction to species within a political management unit.

International Union for Conservation of Nature international organisation

The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable".

Conservation movement social and political advocacy for protecting natural resources

The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to protect natural resources including animal and plant species as well as their habitat for the future.

In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies.


The IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. The aim 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. According to the International Union for Conservation of Nature (IUCN) (1996), the formally stated goals of the Red List are (1) to provide scientifically based information on the status of species and subspecies at a global level, (2) to draw attention to the magnitude and importance of threatened biodiversity, (3) to influence national and international policy and decision-making, and (4) to provide information to guide actions to conserve biological diversity. [1]

Extinction Termination of a taxon by the death of the last member

In biology, extinction is the termination of an organism or of a group of organisms (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" after a period of apparent absence.

Major species assessors include BirdLife International, the Institute of Zoology (the research division of the Zoological Society of London), the World Conservation Monitoring Centre, and many Specialist Groups within the IUCN Species Survival Commission (SSC). Collectively, assessments by these organizations and groups account for nearly half the species on the Red List.

BirdLife International is a global partnership of conservation organisations that strives to conserve birds, their habitats, and global biodiversity, working with people towards sustainability in the use of natural resources. It is the world's largest partnership of conservation organisations, with over 120 partner organisations.

The Institute of Zoology (IoZ) is the research division of the Zoological Society of London (ZSL) in England. It is a government-funded research institute specialising in scientific issues relevant to the conservation of animal species and their habitats. The Institute is based alongside London Zoo at ZSL's Regent's Park site in the City of Westminster.

Zoological Society of London English learned society in zoology

The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826.

The IUCN aims to have the category of every species re-evaluated every five years if possible, or at least every ten years. This is done in a peer reviewed manner through IUCN Species Survival Commission (SSC) Specialist Groups, which are Red List Authorities responsible for a species, group of species or specific geographic area, or in the case of BirdLife International, an entire class (Aves). [2]

Peer review evaluation of work by one or more people of similar competence to the producers of the work

Peer review is the evaluation of work by one or more people with similar competences as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are used to maintain quality standards, improve performance, and provide credibility. In academia, scholarly peer review is often used to determine an academic paper's suitability for publication. Peer review can be categorized by the type of activity and by the field or profession in which the activity occurs, e.g., medical peer review.

As of 2018, 26,197 species are now classified as vulnerable, critical or endangered. [3]


The percentage of species in several groups which are listed as critically endangered,      endangered, or vulnerable on the 2007 IUCN Red List. IUCN Red List 2007.svg
The percentage of species in several groups which are listed as      critically endangered,      endangered, or      vulnerable on the 2007 IUCN Red List.

1964 Red List of Threatened Plants

The 1964 IUCN Red List of Threatened Plants used the older pre-criteria Red List assessment system. Plants listed may not, therefore, appear in the current Red List. IUCN advise that it is best to check both the online Red List and the 1997 plants Red List publication. [4]

2006 release

The 2006 Red List, released on 4 May 2006 evaluated 40,168 species as a whole, plus an additional 2,160 subspecies, varieties, aquatic stocks, and subpopulations.

2007 release

On 12 September 2007, the World Conservation Union (IUCN) released the 2007 IUCN Red List of Threatened Species. In this release, they have raised their classification of both the western lowland gorilla (Gorilla gorilla gorilla) and the Cross River gorilla (Gorilla gorilla diehli) from endangered to critically endangered, which is the last category before extinct in the wild, due to Ebola virus and poaching, along with other factors. Russ Mittermeier, chief of Swiss-based IUCN's Primate Specialist Group, stated that 16,306 species are endangered with extinction, 188 more than in 2006 (total of 41,415 species on the Red List). The Red List includes the Sumatran orangutan (Pongo abelii) in the Critically Endangered category and the Bornean orangutan (Pongo pygmaeus) in the Endangered category. [5]

2008 release

The 2008 Red List was released on 6 October 2008, at the IUCN World Conservation Congress in Barcelona, and "has confirmed an extinction crisis, with almost one in four [mammals] at risk of disappearing forever". The study shows at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction, and 836 are listed as Data Deficient. [6]

2012 release

The Red List of 2012 was released 19 July 2012 at Rio+20 Earth Summit; [7] nearly 2,000 species were added, [8] with 4 species to the extinct list, 2 to the rediscovered list. [9] The IUCN assessed a total of 63,837 species which revealed 19,817 are threatened with extinction. [10] 3,947 were described as "critically endangered" and 5,766 as "endangered," while more than 10,000 species are listed as "vulnerable."[ citation needed ] At threat are 41% of amphibian species, 33% of reef-building corals, 30% of conifers, 25% of mammals, and 13% of birds. [10] The IUCN Red List has listed 132 species of plants and animals from India as "Critically Endangered." [11]


Conservation status
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Lower Risk

Other categories

Related topics

Status iucn3.1.svg
Status TNC.svg

Species are classified by the IUCN Red List into nine groups, [12] specified through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation. There is an emphasis on the acceptability of applying any criteria in the absence of high quality data including suspicion and potential future threats, "so long as these can reasonably be supported.":6 [13]

In the IUCN Red List, "threatened" embraces the categories of Critically Endangered, Endangered, and Vulnerable.

1994 categories and 2001 framework

The older 1994 list has only a single "Lower Risk" category which contained three subcategories:

In the 2001 framework, Near Threatened and Least Concern became their own categories, while Conservation Dependent was removed and its contents merged into Near Threatened.

Possibly extinct

The tag of "possibly extinct" (PE) [14] is used by Birdlife International, the Red List Authority for birds for the IUCN Red List. [15] BirdLife International has recommended PE become an official tag for Critically Endangered species, and this has now been adopted, along with a "Possibly Extinct in the Wild" tag for species with populations surviving in captivity but likely to be extinct in the wild (e.g. Spix's macaw).


Comparing the number of species in each category of IUCN Red List. Sizes of Red List Categories.png
Comparing the number of species in each category of IUCN Red List.

There have been a number of versions, dating from 1991, including: [16] [17]

For plants, the 1997 Red List is the most important source. [18]


1994 IUCN Red List categories (version 2.3), used for species which have not been reassessed since 2001. Status iucn2.3.svg
1994 IUCN Red List categories (version 2.3), used for species which have not been reassessed since 2001.

In 1997, the IUCN Red List received criticism on the grounds of secrecy (or at least poor documentation) surrounding the sources of its data. [19] These allegations have led to efforts by the IUCN to improve its documentation and data quality, and to include peer reviews of taxa on the Red List. The list is also open to petitions against its classifications, on the basis of documentation or criteria. [20] A Nature editorial defended the Red List's relevance in October 2008. [21]

It has been suggested that the IUCN Red List and similar works are prone to misuse by governments and other groups that draw possibly inappropriate conclusions on the state of the environment or to effect exploitation of natural resources. [22]

See also

Related Research Articles

Threatened species

Threatened species are any species which are vulnerable to endangerment 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.

Conservation status Indication of the chance of a species extinction, regardless of authority used

The conservation status of a group of organisms indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation status: not simply the number of individuals remaining, but the overall increase or decrease in the population over time, breeding success rates, and known threats. Various systems of conservation status exist and are in use at international, multi-country, national and local levels as well as for consumer use.

Least-concern species IUCN conservation category

A least concern (LC) species is a species which has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation. They do not qualify as threatened, near threatened, or conservation dependent.

Near-threatened species IUCN conservation category

A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status. The IUCN notes the importance of re-evaluating near-threatened taxon at appropriate intervals.

An endangered species recovery plan is a document describing the current status, threats and intended methods for increasing rare and endangered species population sizes. The U.S. Endangered Species Act of 1973 requires that all species considered endangered must have a plan implemented for their recovery, but the format is also useful when considering the conservation of any endangered species. Recovery plans act as a foundation from which you can build a conservation effort and they can help to make conservation more effective.

Critically endangered IUCN conservation category

A critically endangered (CR) species is one that has been categorized by the International Union for Conservation of Nature (IUCN) as facing an extremely high risk of extinction in the wild.

Data deficient IUCN Red List category

A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessarily indicate 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.

Extinct in the wild IUCN conservation category

A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due to massive habitat loss.

The Committee on the Status of Endangered Wildlife in Canada is an independent committee of wildlife experts and scientists whose "raison d'être is to identify species at risk" in Canada. It designates the conservation status of wild species.

Red-faced parrot species of bird

The red-faced parrot is a species of parrot in the family Psittacidae. It is found in Ecuador and Peru.

The Rio Branco antbird is a bird species in the family Thamnophilidae. It is found in Brazil (Roraima) and Guyana. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist shrubland. It is severely threatened by habitat loss.

Rapanea seychellarum, also known as Bwa Klate, is a species of plant in the Primulaceae family. It is endemic to Seychelles. It is sometimes considered to be a synonym of Rapanea melanophloeos, a mainland African species.

New Zealand Threat Classification System a system to assess the conservation priorities of New Zealand species

The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand.

Endangered species Species of organisms facing a very high risk of extinction

An endangered species is a species which has been categorized as very likely to become extinct in the near future. Endangered (EN), as categorized by the International Union for Conservation of Nature (IUCN) Red List, is the second most severe conservation status for wild populations in the IUCN's schema after Critically Endangered (CR).

Vulnerable species IUCN conservation category

A vulnerable species is one which has been categorized by the International Union for Conservation of Nature as likely to become endangered unless the circumstances that are threatening its survival and reproduction improve.

Not evaluated IUCN Red List category

A not evaluated (NE) species is one which has been categorised under the IUCN Red List of threatened species as not yet having been assessed by the International Union for Conservation of Nature.


  1. CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), Joint Meeting of the Animals and Plants Committees, Shepherdstown (United States of America), 7–9 December 2000, retrieved Nov 14, 2012
  2. "Red List Overview". IUCN Red List. International Union for Conservation of Nature. Archived from the original on 30 June 2014. Retrieved 20 June 2012.CS1 maint: Unfit url (link)
  3. Watts, Jonathan (5 July 2018). "Red list research finds 26,000 global species under extinction threat". The Guardian . Retrieved 14 February 2019.
  4. "Frequently Asked Questions". IUCN. Archived from the original on 27 June 2014. Retrieved 11 October 2011.CS1 maint: Unfit url (link)
  5. IUCN.org news release, Extinction crisis escalates: Red List shows apes, corals, vultures, dolphins all in danger
  6. IUCN Red List reveals world's mammals in crisis
  7. Matthew Knight (19 June 2012). "Extinction threat 'a call to world leaders' at Rio Earth Summit". edition.cnn.com. Retrieved 13 November 2018.
  8. Jessica Phelan (19 June 2012). "IUCN Red List update: Nearly 2,000 species added". www.pri.org. Retrieved 13 November 2018.
  9. "IUCN 2012 update - 4 species extinct – 2 rediscovered – Food security waning". wildlifeextra.com. 19 June 2012. Archived from the original on 4 March 2016. Retrieved 14 November 2018.
  10. 1 2 James Ayre (20 June 2012). "The Red List Of Threatened Species, Annual Report Released". planetsave.com. Retrieved 13 November 2018.
  11. K.S. Sudhi (21 June 2012). "Red list has 132 species of plants, animals from India". thehindu.com. Retrieved 13 November 2018.
  12. Guidelines for Using the IUCN Red List Categories and Criteria (PDF), Version 13, IUCN, March 2017, retrieved 4 January 2018
  13. "IUCN RED LIST CATEGORIES AND CRITERIA Version 3.1 Second edition" (PDF). 2012 International Union for Conservation of Nature and Natural Resources. 2012.
  14. S. H. M. Butchart; et al. "Going or gone: defining 'Possibly Extinct' species to give a truer picture of recent extinctions" (pdf). Bull. B.O.C. 2006 126A.
  15. "Birds on the IUCN Red List". BirdLife International. Retrieved 26 January 2007.
  16. "2001 Categories & Criteria (version 3.1)". IUCN. Archived from the original on 27 June 2014. Retrieved 27 January 2013.CS1 maint: Unfit url (link)
  17. "Historical IUCN Red Data Books and Red Lists". Archived from the original on 27 June 2014. Retrieved 9 June 2016.CS1 maint: Unfit url (link)
  18. "Which IUCN list should I choose?". Botanic Gardens Conservation International.
  19. N. Mrosovsky (1997). "IUCN's credibility critically endangered". Nature. 389 (6650): 436. Bibcode:1997Natur.389..436M. doi:10.1038/38873.
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  21. "The Red List still matters". Nature. 455 (7214): 707–708. 9 October 2008. Bibcode:2008Natur.455R.707.. doi:10.1038/455707b. PMID   18843306.
  22. Hugh P. Possingham; et al. (November 2002). "Limits to the use of threatened species lists". Trends in Ecology & Evolution. 17 (11): 503–507. CiteSeerX . doi:10.1016/S0169-5347(02)02614-9.