||What is the
IUCN Red List?
The IUCN Red List of Threatened Species (also known as the IUCN Red List
or Red Data List), founded in 1964, gives an overview of the global
conservation status of animal and plant species, subspecies and
populations to highlight those threatened with extinction, to guide
conservation action. It is compiled by the
International Union for the Conservation of Nature
(IUCN), specifically the IUCN Global Species Programme and its expert
network known as the
Species Survival Commission (SSC).
The IUCN Red List is continually being updated and is freely available
www.iucnredlist.org. It is based on an
objective system allowing assignment of any species (except
micro-organisms) to one of eight Red List Categories based on whether
they meet criteria linked to population trend, size and structure and
By assessing the threat status of species, the IUCN Red List has two
goals: (i) to identify and document those species most in need of
conservation attention if global extinction rates are to be reduced; and
(ii) to provide a global index of the state of change of biodiversity.
Around 73,000 species have been assessed to-date. This is a tiny
fraction (4.3%) of the world’s described species (with current estimates
of the total number ranging from 5 to 30 million). Of the 73,000,
approximately 60,000 species are currently well documented, with
information on ecology, population size, threats, conservation actions
and utilization. There are also about 45,000 species with distribution
maps. The data cover non-threatened as well as threatened species, and
certain taxonomic groups have been completely or almost completely
Regional and National Red Lists provide
an equivalent method to assess species status at smaller spatial scales
– at the local, national or regional level. See the
What are national Red List assessments?
page for additional information.
The global IUCN Red List only includes information on species,
subspecies or populations that have been globally assessed; regional and
national level assessments are currently not included unless these are
also global assessments (for example, a species that is only found in
one country, (i.e., is endemic) and therefore has the same Red List
status at both national and global levels). For non-endemics, it is
important to note that the status of a species at the global level may
be different to that at a national level. In certain situations, a
species may be listed as threatened on a national Red List even though
it is considered Least Concern at the global level by IUCN and vice
IUCN is also collaborating with other national Red List projects to
incorporate their data, especially on national endemics, into the global
IUCN Red List. IUCN and its Red List Partners are currently discussing
how to disseminate the data in the national and regional Red Lists more
effectively, especially those that are conducted using the IUCN
As it is not possible to evaluate all known species, the IUCN and the
SSC are working to cover key taxonomic groups: The Biodiversity
Assessment Initiative aims to provide an effective method for gathering
scientific data available for biodiversity conservation.
The first taxonomic group to be completely assessed under the Initiative
was amphibians (frogs, toads, salamanders, and caecilians). The results
of the Global Amphibian Assessment (GAA), released in 2004, were
alarming: one in three amphibian species face extinction.
While updates to the amphibian database have been incremental, there has
not been a major comprehensive amphibian assessment since 2004. Since
2004 the database has been slowly but continually updated to include
newly-described or revalidated species and new information. The
assessment of amphibians is ongoing and relies on the expertise of
hundreds of herpetologists from all around the world. For further
information on the assessment process see the
Amphibian Assessment Forum.
The IUCN Red List uses 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 first Red List Criteria were adopted in 1994 (IUCN, 1994) after a
wide consultative process involving hundreds of scientists. The IUCN Red
List Categories and Criteria were revised in 2001 (IUCN, 2001). Each
species assessed is assigned to one of the following categories:
Extinct, Extinct in the Wild, Critically Endangered, Endangered,
Vulnerable, Near Threatened, Least Concern and Data Deficient, based on
a series of quantitative criteria linked to population trend, population
size and structure, and geographic range. Species classified as
Vulnerable, Endangered and Critically Endangered are regarded as
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)
The IUCN Species Programme plays the lead role in helping to fund,
convene and facilitate the assessment workshops which drive much of the
data gathering and review process for the Red List.
All species assessments are based on data currently available for the
species (or subspecies, population) across its entire global range.
Categories and definitions
A taxon is Extinct when there is no reasonable doubt that the last
individual has died. A taxon is presumed Extinct when exhaustive surveys
in known and/or expected habitat, at appropriate times (diurnal,
seasonal, annual), throughout its historic range have failed to record
an individual. Surveys should be over a time frame appropriate to the
taxon’s life cycle and life form.
Extinct in the Wild (EW)
A taxon is Extinct in the Wild when it is known only to survive in
cultivation, in captivity or as a naturalized population (or
populations) well outside the past range. A taxon is presumed Extinct in
the Wild when exhaustive surveys in known and/or expected habitat, at
appropriate times (diurnal, seasonal, annual), throughout its historic
range have failed to record an individual. Surveys should be over a time
frame appropriate to the taxon’s life cycle and life form.
Critically Endangered (CR)
A taxon is Critically Endangered when the best available evidence
indicates that it meets any of the criteria A to E for Critically
Endangered (see Section V), and it is therefore considered to be facing
an extremely high risk of extinction in the wild.
A taxon is Endangered when the best available evidence indicates that it
meets any of the criteria A to E for Endangered (see Section V), and it
is therefore considered to be facing a very high risk of extinction in
A taxon is Vulnerable when the best available evidence indicates that it
meets any of the criteria A to E for Vulnerable (see Section V), and it
is therefore considered to be facing a high risk of extinction in the
Near Threatened (NT)
A taxon is Near Threatened when it has been evaluated against the
criteria but does not qualify for Critically Endangered, Endangered or
Vulnerable now, but is close to qualifying for or is likely to qualify
for a threatened category in the near future.
Least Concern (LC)
A taxon is Least Concern when it has been evaluated against the criteria
and does not qualify for Critically Endangered, Endangered, Vulnerable
or Near Threatened. Widespread and abundant taxa are included in this
Data Deficient (DD)
A taxon is Data Deficient when there is inadequate information to make a
direct, or indirect, assessment of its risk of extinction based on its
distribution and/or population status. A taxon in this category may be
well studied, and its biology well known, but appropriate data on
abundance and/or distribution are lacking. Data Deficient is therefore
not a category of threat. Listing of taxa in this category indicates
that more information is required and acknowledges the possibility that
future research will show that threatened classification is appropriate.
It is important to make positive use of whatever data are available. In
many cases great care should be exercised in choosing between DD and a
threatened status. If the range of a taxon is suspected to be relatively
circumscribed, and a considerable period of time has elapsed since the
last record of the taxon, threatened status may well be justified.
Not Evaluated (NE)
A taxon is Not Evaluated when it has not yet been evaluated against the