Introduction
The
IUCN Red List of Threatened Species™ is widely recognized as the most
comprehensive, objective global approach for evaluating the conservation status
of plant and animal species.
The
IUCN Red List assesses the extinction risk of species. Assessments of all
mammals, birds, amphibians, sharks, reef-building corals, cycads and conifers
have been completed. Efforts are underway to assess all reptiles, fishes and
selected groups of plants and invertebrates. This sample indicates how life on Earth
is faring, how little is known, and how urgent the need is to assess more
species. In this way, The IUCN Red List is becoming The Barometer of Life.
The IUCN Red List
partnership
The
IUCN Red List is produced and managed by the IUCN Global Species Programme and
the Species Survival Commission (SSC). The IUCN Red List Partnership consists
of members and partners of IUCN who are making a particularly significant
contribution to The IUCN Red List of Threatened Species ™. This takes the form
of technical or financial support or both. The Partnership currently consists
of:
·
BirdLife International
·
Botanic Gardens Conservation International (BGCI)
·
Conservation International
·
Sapienza Università di Roma
·
NatureServe
·
Royal Botanic Gardens Kew
·
Texas A&M University
·
Wildscreen
·
Zoological Society of London
A Brief History of the IUCN
Red List
·
1963 - the IUCN Red List System was first conceived
·
1988 – all bird species were evaluated
·
1994 – a more precise and quantitative Red List Categories and Criteria were
adopted
·
1996 – all mammal species were evaluated
The Categories
Extinct
|
EX
|
Extinct in the Wild
|
EW
|
Critically
Endangered
|
CR
|
Endangered
|
EN
|
Vulnerable
|
VU
|
Near
Threatened
|
NT
|
Least
Concern
|
LC
|
Data
Deficient
|
DD
|
Not
Evaluated
|
NE
|
Extinct (EX)
A
taxon is Extinct when there is no reasonable doubt that the last individual has
died. A taxon is presumed Extinct when
exhaustive surveys is know 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 survived 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 meet any of the criteria for Critically Endangered, and it is therefore
considered to be facing an extremely high risk of extinction in the wild.
A.
Reduction in population size base on any of the following :
1. An observed, estimated, inferred or suspected
population size reduction of ³90% over the last 10 years or
three generations, whichever is the longer, where the causes of the reduction
are clearly reversible AND understood AND ceased, based on (and specifying) any
of the following :
(a) direct observation
(b) an index of abundance appropriate to 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, hybridization,
pathogens, pollutants, competitors or parasites.
2. An observed, estimated, inferred or suspected
population size reduction of ³80% over the last 10 years or
three generations, whichever is the longer, where the reduction or its causes
may not have ceased OR may not be understood OR may not be reversible base on
(and specifying) any of (a) to (e) under A1.
3. A population size reduction of ³80%, projected or suspected to
be met within the next 10 years or three generations, whichever is the longer
(up to a maximum of 100 years), based on (and specifying) any of (b) to (e)
under A1.
4. An observed, estimated, inferred, projected or
suspected population size reduction of ³80% over any 10 year or three
generation period, whichever is longer (up to a maximum of 100 years in the
future), where the time period must include both the past and the future, and
where the reduction or its causes may not have ceased OR may not be understood
OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.
B.
Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of
occupancy) OR both :
1. Extent of occurrence estimated to be less than 100km2 , and estimates
indicating at least two of (a) to (c) :
(a) severely fragmented or known to exist at only a
single location.
(b) continuing decline, observed, inferred or
projected, in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)area,
extent and/or quality of habitat
(iv)
number of locations or subpopulations
(v)
number of mature individuals.
(c) extreme fluctuations in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)number
of locations or subpopulations
(iv)
number of mature individuals.
2. Area of occupancy estimated to be less than 10km2 , and estimate indicating
at least two of 1(a) to 1(c).
C.
Population size estimated to number fewer than 250
mature individuals and either :
1. an estimated continuing decline of at least 25% within three years or one
generation, whichever is longer, (up to a maximum of 100 years in the
future) OR
2. a continuing decline, observed, projected, or
inferred, in numbers of mature individual AND at least one of the following :
(a) population structure in the form of the
following :
(i) no
subpopulation estimated to contain more than 50
mature individuals, OR
(ii)
at least 90% of mature individuals in one
subpopulation.
(b) extreme fluctuations in number of mature
individuals.
D.
Population size estimated to number fewer 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 (up to a maximum of 100 years).
Endangered
(EN)
A
taxon is Endangered when the best available evidence indicates that it meet any
of the criteria for Endangered , and it is therefore considered to be facing an
extremely high risk of extinction in the wild.
A.
Reduction in population size base on any of the following :
1. An observed, estimated, inferred or suspected
population size reduction of ³70% over the last 10 years or
three generations, whichever is the longer, where the causes of the reduction
are clearly reversible AND understood AND ceased, based on (and specifying) any
of the following :
(a) direct observation
(b) an index of abundance appropriate to 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, hybridization,
pathogens, pollutants, competitors or parasites.
2. An observed, estimated, inferred or suspected
population size reduction of ³50% over the last 10 years or
three generations, whichever is the longer, where the reduction or its causes
may not have ceased OR may not be understood OR may not be reversible base on
(and specifying) any of (a) to (e) under A1.
3. A population size reduction of ³50%,
projected or suspected to be met within the next 10 years or three generations,
whichever is the longer (up to a maximum of 100 years), based on (and
specifying) any of (b) to (e) under A1.
4. An observed, estimated, inferred, projected or
suspected population size reduction of ³50% over any 10 year or three
generation period, whichever is longer (up to a maximum of 100 years in the
future), where the time period must include both the past and the future, and
where the reduction or its causes may not have ceased OR may not be understood
OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.
B.
Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of
occupancy) OR both :
1. Extent of occurrence estimated to be less than 5,000km2 , and estimates
indicating at least two of (a) to (c) :
(a) severely fragmented or known to exist at more
than five locations.
(b) continuing decline, observed, inferred or
projected, in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)area,
extent and/or quality of habitat
(iv)
number of locations or subpopulations
(v)
number of mature individuals.
(c) extreme fluctuations in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)number
of locations or subpopulations
(iv)
number of mature individuals.
2. Area of occupancy estimated to be less than 500km2 , and estimate
indicating at least two of 1(a) to 1(c).
C.
Population size estimated to number fewer than 2,500
mature individuals and either :
1. an estimated continuing decline of at least 20% within five years
or two generation, whichever is longer, (up to a maximum of 100 years in
the future) OR
2. a continuing decline, observed, projected, or
inferred, in numbers of mature individual AND at least one of the following :
(a) population structure in the form of the
following :
(i) no subpopulation
estimated to contain more than 250
mature individuals, OR
(ii)
at least 90% of mature individuals in one
subpopulation.
(b) extreme fluctuations in number of mature
individuals.
D.
Population size estimated to number fewer than 250
mature individuals.
E.
Quantitative analysis showing the probability of extinction in the wild is at
least 20% within 20
years or five generations, whichever is the longer (up to a maximum of
100 years).
Vunerable
(VU)
A
taxon is Vulnerable when the best available evidence indicates that it meet any
of the criteria for Vulnerable , and it is therefore considered to be facing an
extremely high risk of extinction in the wild.
A.
Reduction in population size base on any of the following :
1. An observed, estimated, inferred or suspected
population size reduction of ³50% over the last 10 years or
three generations, whichever is the longer, where the causes of the reduction
are clearly reversible AND understood AND ceased, based on (and specifying) any
of the following :
(a) direct observation
(b) an index of abundance appropriate to 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, hybridization,
pathogens, pollutants, competitors or parasites.
2. An observed, estimated, inferred or suspected
population size reduction of ³30% over the last 10 years or
three generations, whichever is the longer, where the reduction or its causes
may not have ceased OR may not be understood OR may not be reversible base on
(and specifying) any of (a) to (e) under A1.
3. A population size reduction of ³30%,
projected or suspected to be met within the next 10 years or three generations,
whichever is the longer (up to a maximum of 100 years), based on (and
specifying) any of (b) to (e) under A1.
4. An observed, estimated, inferred, projected or
suspected population size reduction of ³30% over any 10 year or three
generation period, whichever is longer (up to a maximum of 100 years in the
future), where the time period must include both the past and the future, and
where the reduction or its causes may not have ceased OR may not be understood
OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.
B.
Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of
occupancy) OR both :
1. Extent of occurrence estimated to be less than 20,000km2 , and estimates
indicating at least two of (a) to (c) :
(a) severely fragmented or known to exist at more
than 10 locations.
(b) continuing decline, observed, inferred or
projected, in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)area,
extent and/or quality of habitat
(iv)
number of locations or subpopulations
(v)
number of mature individuals.
(c) extreme fluctuations in any of the following :
(i) extent of occurrence
(ii)
area of occupancy
(iii)number
of locations or subpopulations
(iv)
number of mature individuals.
2. Area of occupancy estimated to be less than 2,000km2 , and estimate
indicating at least two of 1(a) to 1(c).
C.
Population size estimated to number fewer than 10,000
mature individuals and either :
1. an estimated continuing decline of at least 10% within 10 years or
three generations, whichever is longer, (up to a maximum of 100 years in
the future) OR
2. a continuing decline, observed, projected, or
inferred, in numbers of mature individual AND at least one of the following :
(a) population structure in the form of the following
:
(i) no
subpopulation estimated to contain more than 1,000
mature individuals, OR
(ii)
all mature individuals in one subpopulation.
(b) extreme fluctuations in number of mature
individuals.
D.
Population very small or restricted in the form of either of the following :
1. population size estimated to number fewer than
1,000 mature individuals.
2. population with a very restricted area of
occupancy (typically less than 20km2) or number of locations
(typically five or fewer) such that is prone to the effects of human activities
or stochastic events within a very short time period in an uncertain future,
and is thus capable of becoming Critically Endangered or ever Extinct in a very
short time period.
E.
Quantitative analysis showing the probability of extinction in the wild is at
least 10% within 100
years.
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 evaluated against the criteria and does not
qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant taxa are included in
the category.
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 studies, and its biology well know, 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 criteria.
