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EXTINCT (EX) - A taxon is Extinct when there is no reasonable doubt that the last
individual has died.
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 naturalised
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 it is facing an extremely high risk of extinction in
the wild in the immediate future, as defined by any of the
criteria (A to E) as described below.
ENDANGERED (EN) -
A taxon is Endangered when it is not Critically Endangered
but is facing a very high risk of extinction in the wild
in the near future, as defined by any of the criteria (A
to E) as described below.
VULNERABLE (VU) -
A taxon is Vulnerable when it is not Critically Endangered
or Endangered but is facing a high risk of extinction in
the wild in the medium-term future, as defined by any of
the criteria (A to E) as described below.
LOWER RISK (LR) -
A taxon is Lower Risk when it has been evaluated, does
not satisfy the criteria for any of the categories Critically
Endangered, Endangered or Vulnerable. Taxa included in the
Lower Risk category can be separated into three subcategories:
- Conservation Dependent (cd).
Taxa which are the focus of a
continuing taxon-specific or habitat-specific conservation
programme targeted towards the taxon in question, the
cessation of which would result in the taxon qualifying
for one of the threatened categories above within a period
of five years.
- Near Threatened (nt).
Taxa which do not qualify for Conservation Dependent,
but which are close to qualifying for Vulnerable.
- Least Concern (lc).
Taxa which do not qualify for Conservation Dependent
or Near Threatened.
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
is lacking. Data Deficient is therefore not a category of
threat or Lower Risk. 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 threatened status. If the range
of a taxon is suspected to be relatively circumscribed, if
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 is has not yet been assessed
against the criteria.
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The criteria for Critically
Endangered, Endangered and Vulnerable
| CRITICALLY ENDANGERED (CR) |
| A taxon is Critically
Endangered when it is facing an extremely high risk of extinction
in the wild in the immediate future, as defined by any of
the following criteria (A to E): |
| A) |
Population reduction in the form
of either of the following: |
| 1) |
An observed, estimated, inferred
or suspected reduction of at least 80% over the last
10 years or three generations, whichever is the longer,
based on (and specifying) any of the following: |
| a) |
direct observation |
| b) |
an index of abundance
appropriate for the taxon |
| c) |
a decline in area of
occupancy, extent of occurrence and/or quality
of habitat |
| d) |
actual or potential
levels of exploitation |
| e) |
the effects of introduced
taxa, hybridisation, pathogens, pollutants, competitors
or parasites. |
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| 2) |
A reduction of at least 80%,
projected or suspected to be met within the next 10
years or three generations, whichever is the longer,
based on (and specifying) any of (b), (c), (d) or (e)
above. |
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| B) |
Extent of occurrence estimated to
be less than 100 km2 or area of occupancy estimated
to be less than 10 km2, and estimates indicating
any two of the following: |
| 1) |
Severely fragmented or known
to exist at only a single location. |
| 2) |
Continuing decline, observed,
inferred or projected, in any of the following: |
| a) |
extent of occurrence |
| b) |
area of occupancy |
| c) |
area, extent and/or
quality of habitat |
| d) |
number of locations
or subpopulations |
| e) |
number of mature individuals |
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| 3) |
Extreme fluctuations in any
of the following: |
| a) |
extent of occurrence |
| b) |
area of occupancy |
| c) |
number of locations
or subpopulations |
| d) |
number of mature individuals |
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| C) |
Population estimated to number less
than 250 mature individuals and either: |
| 1) |
An estimated continuing decline
of at least 25% within three years or one generation,
whichever is longer or |
| 2) |
A continuing decline, observed,
projected, or inferred, in numbers of mature individuals
and population structure in the form of either: |
| a) |
severely fragmented
(i.e. no subpopulation estimated to contain more
than 50 mature individuals)
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| b) |
all individuals are
in a single subpopulation |
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| D) |
Population estimated to number less
than 50 mature individuals. |
| E) |
Quantitative analysis showing the
probability of extinction in the wild is at least 50% within
10 years or three generations, whichever is the longer. |
© 2001 International
Union for Conservation of Nature and Natural Resources,
Contact Information
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