Introduction to the IUCN
Red Listing Process
IUCN (International Union for Conservation of Nature)
The IUCN Red List assessment
estimates risk of extinction
What is the likelihood of a species becoming
extinct in the near future, given current
knowledge about population trends, range, and
recent, current or projected threats?
IUCN (International Union for Conservation of Nature)
The IUCN Red List
Categories &
Criteria
All materials are freely
available on IUCN Red
List web site:
www.iucnredlist.org
IUCN (International Union for Conservation of Nature)
Scope of Application
The IUCN Red List Categories and Criteria are:
•
•
•
Used to assess taxa at the global level
Can be used at regional levels (but see the Guidelines for Application of
IUCN Red List Criteria at Regional Levels)
Used to assess wild populations inside their natural range (including
populations resulting from benign introductions)
IUCN Categories and Criteria can be applied to:
•
•
All described taxa (species, subspecies, varieties), except micro-organisms
Taxa not yet formally described, but only if they are:
• A clearly distinct species
• Museum/herbarium voucher references are provided
• Distribution information is available
• There is clear conservation benefit to assessing the species
IUCN (International Union for Conservation of Nature)
Rabb’s Fringe-limbed Treefrog
Ecnomiohyla rabborum
Category: Critically Endangered
CR A2ace;B1ab(iii)
Criteria & subcriteria
IUCN (International Union for Conservation of Nature)
The
IUCN
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)
IUCN (International Union for Conservation of Nature)
Extinct (EX)
A taxon is Extinct when there is no reasonable
doubt that the last individual has
died
Extinct in the Wild (EW)
Dodo, Raphus cucullatus
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
IUCN (International Union for Conservation
of Nature)
Photo © Craig Hilton-Taylor
Franklinia,
Franklinia alatamaha
A taxon is threatened when the best available evidence
indicates that it meets any of the criteria A to E for the
thresholds stated in one of the three threatened categories:
Critically Endangered, Endangered or Vulnerable.
Critically Endangered (CR)
CR taxa are considered to be facing an extremely
high risk of extinction in the wild
Photo © Wendy Strahm
Endangered (EN)
Mandrinette, Hibiscus
fragilis
EN taxa are considered to be facing a
very high risk of extinction in the wild
Black-browed Albatross,
Thalassarche
melanophrys
Photo © Tony Palliser
Vulnerable (VU)
Golden Pagoda,
VU taxa are considered to be facing a high risk
of
IUCN (International Union for Conservation
Mimetes of Nature)
extinction in the wild
chrysanthus
Photo © Craig HiltonTaylor
Near Threatened (NT)
A taxon is Near Threatened when it has been evaluated
against the criteria and does not qualify for CR, EN or
VU now, but is close to qualifying for
or is likely to qualify for a threatened
category in the near future
Photo © H. Fraga
Macaronesian Laurel, Laurus azorica
Least Concern (LC)
A taxon is Least Concern when it has been evaluated against
the criteria and does not qualify for CR, EN,
VU or NT. Widespread and abundant taxa
are included in this category
IUCN (International Union for Conservation of Nature)
Photo © Caroline Pollock
Olive Baboon, Papio anumbis
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
Tree Tomato
Solanum [Cyphomandra] betacea
Not Evaluated (NE)
A taxon is Not Evaluated when it has not
yet been evaluated against the criteria IUCN (International Union for Conservation of Nature)
Data Deficient (DD)
Not Evaluated (NE)
Although DD and NE are not
threatened categories, taxa classed
as DD or NE should NOT be treated as
not threatened
IUCN (International Union for Conservation of Nature)
Types of data required for
IUCN Red List assessments
IUCN (International Union for Conservation of Nature)
Dealing with a lack of high
quality data
• The threatened categories use
quantitative thresholds
• BUT a lack of high quality data should
not deter assessors from applying the
IUCN criteria
IUCN (International Union for Conservation of Nature)
Acceptable types of data quality
Observed
Estimated
Projected
Inferred
Suspected
IUCN (International Union for Conservation of Nature)
Observed
Observed information is directly based on well-documented
observations of all known individuals in the population
Estimated
Estimated information is based on calculations that may involve
assumptions
Projected
Projected information is the same as “estimated”, but the variable of
interest is extrapolated in time towards the future
IUCN (International Union for Conservation of Nature)
Inferred
Inferred information is based on variables that are indirectly
related to the variable of interest, but in the same general type of
units (e.g. number of individuals or area or number of
subpopulations)
Suspected
Suspected information is based on circumstantial evidence, or
on variables in different types of units. In general, this can be
based on any factor related to population abundance or
distribution
IUCN (International Union for Conservation of Nature)
Dealing with uncertainty
Information uncertainty must be taken into account when making an
assessment
Uncertainty can have a strong effect on assessments:
• If uncertainty causes a wide variation in possible assessments,
note must be taken of the range of possibilities. Only one
category is to be chosen, and the basis for that decision must be
documented and should be precautionary but also reliable
• When there is much uncertainty associated with any given
information the Data Deficient category can be applied
IUCN (International Union for Conservation of Nature)
Attitudes towards uncertainty
Sources of uncertainty (Akçakaya et al. 2000):
•
Semantic uncertainty
•
Measurement error
•
Natural variability
Uncertainty can lead to differing assessments because
different aspects of uncertainty are emphasized
Precautionary
Evidentiary
IUCN (International Union for Conservation of Nature)
Concepts and definitions
underlying the IUCN Red List
Categories and Criteria
IUCN (International Union for Conservation of Nature)
Key terms used in the IUCN Red
List criteria
Population and Population Size
Subpopulations
Mature Individuals
Generation Length
Reduction
Continuing Decline
IUCN (International Union for Conservation of Nature)
Key terms used in the IUCN Red
List criteria
Extreme Fluctuations
Severely Fragmented
Extent of Occurrence
Area of Occupancy
Location
Quantitative Analysis
IUCN (International Union for Conservation of Nature)
Population and Population Size
Population is the total number of individuals of a given taxon across its
global range
Population size is measured as the number of mature individuals only
Subpopulations
Subpopulations are geographically or otherwise distinct groups in the
population between which there is little demographic exchange (e.g., 1
successful migrant individual or gamete per year)
Mature Individuals
Mature Individuals are individuals that are known, estimated or inferred
to be capable of reproduction
IUCN (International Union for Conservation of Nature)
Population
Subpopulations
Population Size
(mature individuals only)
IUCN (International Union for Conservation of Nature)
Generation Length
Generation Length is the average age of parents of the current cohort
(i.e., newborn individuals in the population)
•
Greater than the age at first breeding and less than the oldest breeding
individual, except in taxa that breed only once
•
Reflects turnover rate of breeding individuals in a population.
•
Scales all time-based measurements in the criteria to account for
different rates at which taxa survive and reproduce
•
Where generation length varies under threat, use the more natural (i.e.
pre-disturbance) generation length
IUCN (International Union for Conservation of Nature)
Reduction
Reduction is a decline in population
size of at least the % stated in criterion
A over the specified time period
Population
Size
Time
Continuing Decline
Continuing Decline is a recent,
current or projected future decline
which is liable to continue unless
(International Union
Conservation of Nature)
remedial IUCN
measures
are fortaken
Extreme Fluctuations
Extreme Fluctuations occur in a number of taxa where
population size or distribution area varies widely, rapidly and
frequently, typically with a variation greater than one order of
magnitude (i.e., a tenfold increase of decrease)
IUCN (International Union for Conservation of Nature)
Extreme Fluctuations
25,000
20,000
15,000
10,000
5,000
0
Jan '02
July '02
Jan '03
July '03
Jan '04
July '04
Jan '05
July '05
Jan '06
Natural seasonal fluctuations – flux of individuals
between different life stages. Not real changes in total
population size, therefore not extreme fluctuation
July '06
IUCN (International Union for Conservation of Nature)
Extreme Fluctuations
25,000
20,000
15,000
10,000
5,000
0
Jan '02
July '02
Jan '03
July '03
Jan '04
July '04
Jan '05
July '05
Jan '06
July '06
Natural seasonal fluctuations, with threatening events also
causing very large population size variations during reproductive
seasons (e.g., dormant eggs/seeds damaged or lost). Real
changes in total population size, therefore
extreme fluctuation
IUCN (International Union for Conservation of Nature)
Severely Fragmented
Severely Fragmented refers to the situation in which
increased extinction risks to the taxon result from the fact that
most of its individuals are found in relatively isolated
subpopulations
IUCN (International Union for Conservation of Nature)
Severely Fragmented
The existence of small and isolated habitat patches alone is not
enough to consider a taxon to be severely fragmented – there should
also be knowledge about the taxon’s dispersal ability
Taxa with highly mobile adult stages or
producing large numbers of small, mobile
diaspores can disperse more easily and
are not so vulnerable to isolation through
fragmented habitats
Taxa producing small numbers of
diaspores (or none at all), or only large
ones are less able to disperse over wide
areas and are more easily isolated
IUCN (International Union for Conservation of Nature)
Extent of Occurrence
Area of Occupancy
Extent of Occurrence is the area
contained within the shortest
continuous imaginary boundary
which can be drawn to encompass
all known, inferred, or projected sites
presently occupied by the taxon
Area of Occupancy is the area
within the Extent of Occurrence
which is actually occupied by the
taxon (measured by overlaying a
grid and counting number of
occupied cells)
IUCN (International Union for Conservation of Nature)
Extent of Occurrence
Comparison of taxa with same AOO but different EOO – a single threatening event is
more likely to rapidly have a major impact on the taxon with the smaller EOO than the
taxon with the larger EOO:
Threatening
event
AOO = 10x4 = 40 km2
2
AOO
10x4 = Union
40 km
IUCN=
(International
for Conservation of Nature)
EOO = 44 km²
EOO = 105 km²
Extent of Occurrence
Comparison of taxa with same AOO but different EOO – a single threatening event is
more likely to rapidly have a major impact on the taxon with the smaller EOO than the
taxon with the larger EOO:
One major threatening event caused:
One major threatening event caused:
30% decline in AOO, 36% decline
in EOO, >39% decline in population
size
20% decline in AOO, 22% decline
in EOO, <20% decline in population
size
AOO = 7x4 = 28 km2
2
AOO IUCN
= 8x4
= 32 km
(International
Union for Conservation of Nature)
EOO = 28 km²
EOO = 82 km²
Area of Occupancy
Problems of Scale
Grid Cells 16 units²
AOO = 3 x 16 = 48 units2
Grid Cell = 1 unit²
AOO = 10 x 1 = 10 units2
IUCN
(International
for Conservation
In many cases, a grid size of 2 km (i.e.,
cell
areaUnion
4 km²)
is anof Nature)
appropriate scale
Location
Location is a geographically or
ecologically distinct area in which a
single threatening event can rapidly
affect all individuals of the taxon
IUCN (International Union for Conservation of Nature)
Location
Invasive
species
2 locations
IUCN (International Union for Conservation of Nature)
Location
Pollution
4 locations
IUCN (International Union for Conservation of Nature)
Location
4-5
locations
Pollution
IUCN (International Union for Conservation of Nature)
Quantitative Analysis
Quantitative Analysis is any form
of analysis which estimates the
extinction probability of a taxon
based on known life history, habitat
requirements, threats and any
specified management options
(e.g., Population Viability Analysis
(PVA))
= oh ohh!
IUCN (International Union for Conservation of Nature)
The IUCN Red List Criteria
IUCN (International Union for Conservation of Nature)
Nature of the Criteria
THREATENED
CATEGORIES
CRITERIA
A
Population
reduction
B
Restricted
geographic range
C
Small population
size & decline
D
Very small or
restricted
population
E
Quantitative
analysis
Critically Endangered (CR)
Quantitative
thresholds
Endangered (EN)
Vulnerable (VU)
IUCN (International Union for Conservation of Nature)
Why use multiple criteria?
Not all the criteria are appropriate to all taxa
•
•
•
All taxa being assessed must be evaluated
against each criterion
Meeting any one of the criteria qualifies a
taxon for listing at that level of threat
All criteria met at the highest level of threat
should be listed
IUCN (International Union for Conservation of Nature)
IUCN (International Union for Conservation of Nature)
Criterion A
Past, present or future population reduction
Population
Size
Time
IUCN (International Union for Conservation of Nature)
Criterion A
Based on any of four subcriteria:
A1: Population reduction in past and causes of
decline now ceased
A2: Population reduction in past and causes of
decline ongoing
A3: Population reduction expected in future
A4: Population reduction in past AND future
IUCN (International Union for Conservation of Nature)
Subcriterion A1
past reduction & causes
understood & ceased &
reduction is reversible
 50% Vulnerable
 70% Endangered
 90% Critically Endangered
Present
Last 10 years or 3 generations
(whichever is longer)
Subcriterion A2
past reduction & causes
may not be understood
or may not have ceased
or reduction may not be
reversible
 30% Vulnerable
 50% Endangered
 80% Critically Endangered
Present
IUCN (International
Last 10 years or 3 generations
(whichever is longer)
Union for Conservation of Nature)
Subcriterion A3
future decline
 30% Vulnerable
 50% Endangered
 80% Critically Endangered
Present
Next 10 years or 3 generations
(whichever is longer up to a maximum of 100
years)
Subcriterion A4
past & future
 30% Vulnerable
 50% Endangered
 80% Critically
Endangered
Present
10 years or 3 generationsIUCN (International Union for Conservation of Nature)
(whichever is longer, up to a maximum of 100 years in the future)
including some time in the past AND in the future
Subcriterion A4
past & future: “shifting time window”
generations
10 years 10
/ 3 years
generations
10/ 3years
/ 3 generations
years
1.5 / 1
years
3.3// 2years
years
/2
3.356.6
years
/ /11.5
6.65 years
generations
generations
generation
generations
generation
generations
Present
IUCN (International Union for Conservation of Nature)
For ALL the subcriteria (A1–A4), rate of population
reduction should be based on any of:
(a) Direct observation
(not for subcriterion A3 – future reduction)
(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
• parasites
IUCN
(International Union for Conservation of Nature)
Use any of the criteria A-E
A. Population reduction
Critically Endangered
Endangered
Vulnerable
Declines measured over the longer of 10 years or 3 generations
A1
 90%
 70%
 50%
A2, A3 & A4
 80%
 50%
 30%
A1. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are
clearly reversible AND understood AND have 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 (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) Effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction may
not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years), based on (b) to
(e) under A1.
A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years)
where the time period must include both the past and the future, and where the causes of reduction may not have
(International
Union for Conservation of Nature)
ceased OR may not be understood OR may not be reversible, based onIUCN
(a) to
(e) under A1.
Criterion A
Points to remember:
• Reduction in population size may be a one-off event, or may be
continuing
• Subcriterion A1 has higher thresholds than the other sub-criteria
• For subcriterion A1, causes of population decline must be understood
AND must have ceased AND the reduction is reversible
• Subcriterion A3 based on declines projected into the FUTURE,
therefore it cannot be based on direct observation
• Subcriterion A4 (the “shifting time window”) must include some time in
the past AND some time in the future
• All time measurements are based on ten years OR 3 generations
whichever is the longer time period (100 year time cap in future)
IUCN (International Union for Conservation of Nature)
Criterion B
Restricted geographic range and
fragmentation, continuing decline or extreme
fluctuations
IUCN (International Union for Conservation of Nature)
Criterion B
Based on either of two subcriteria:
B1: Estimated extent of occurrence
AND / OR
B2: Estimated area of occupancy
AND at least TWO of a-c:
a. Severely fragmented or few locations
b. Continuing decline
c. Extreme fluctuations
IUCN (International Union for Conservation of Nature)
Criterion B
Subcriterion B1
Subcriterion B2
Extent of occurrence
estimated to be:
Area of occupancy
estimated to be:
CR
< 100 km²
< 10 km²
EN
< 5,000 km²
< 500 km²
VU
< 20,000 km²
< 2,000 km²
IUCN (International Union for Conservation of Nature)
Criterion B
AND at least TWO of a, b or c:
a. Severely
fragmented or
# locations:
CR
EN
VU
1
5
 10
b. Continuing decline in
any of the following:
c. Extreme fluctuation in
any of the following:
(i) EOO
(i) EOO
(ii) AOO
(ii) AOO
(iii)Area, extent and/or
quality of habitat
(iii) # locations or
subpopulations
(iv) # locations or
subpopulations
(iv) # mature individuals
(v) # mature individuals
IUCN (International Union for Conservation of Nature)
Use any of the criteria A-E
Critically Endangered
Endangered
Vulnerable
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence
< 100 km²
< 5,000 km²
< 20,000 km²
B2. Area of occupancy
< 10 km²
< 500 km²
< 2,000 km²
=1
≤5
≤ 10
AND at least 2 of the following
(a) Severely fragmented, OR
Number of locations
(b) Continuing decline in any of: (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: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or
subpopulations; (iv) number of mature individuals
IUCN (International Union for Conservation of Nature)
Criterion B
Points to remember:
• Subcriterion B1 is based on extent of occurrence, while sub-criterion
B2 is based on area of occupancy
• Either subcriteria B1 or B2, or both may apply
• To fully qualify for a listing under criterion B, the taxon must meet at
least two of the subcriteria a, b or c
• Subcriterion B1a / B2a may be based on either severe fragmentation
OR number of locations – please remember the definitions of these
terms when applying them
IUCN (International Union for Conservation of Nature)
Criterion C
Small population size and continuing decline
IUCN (International Union for Conservation of Nature)
Criterion C
Based on small population size AND either C1 or C2:
C1: Continuing decline in population size at a specified rate
OR
C2: Continuing decline in population size at any, unspecified rate
AND either C2a or C2b:
C2a: (i) very small subpopulations, OR (ii) most mature
individuals are in one subpopulation
C2b: extreme fluctuations in number of mature individuals
IUCN (International Union for Conservation of Nature)
Criterion C
Thresholds for criterion C
Population size is estimated at:
CR
< 250 mature individuals
EN
< 2,500 mature individuals
VU
< 10,000 mature individuals
IUCN (International Union for Conservation of Nature)
Criterion C
Subcriterion C1
Estimated continuing decline of:
CR
 25% within 3 years or 1
generation
EN
 20% within 5 years or 2
generations
VU
 10% within 10 years or 3
generations
IUCN (International Union for Conservation of Nature)
Criterion C
Subcriterion C2
Observed, projected or inferred continuing decline at any rate
AND at least one of the following:
CR
C2a(i).
C2a(ii).
All subpopulations
have:
One subpopulation
contains:
< 50 mature
individuals
EN
< 250 mature
individuals
VU
< 1,000 mature
individuals
 90% of the
mature
individuals
C2b.
 95% of the
mature
individuals
There are
extreme
fluctuations in
number of
mature
individuals
100% of the
mature
IUCN (International Union for Conservation of Nature)
individuals
Use any of the criteria A-E
Endangered
Vulnerable
< 250
< 2,500
< 10,000
25% in 3 years or 1
generation
20% in 5 years or 2
generations
10% in 10 years or 3
generations
< 250
< 1,000
95-100%
100%
Critically Endangered
C. Small population size and decline
Number of mature individuals
AND either C1 or C2:
C1. An estimated continuing
decline of at least:
(up to a maximum of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) number of mature
< 50
individuals in each
subpopulation:
(a ii) or % individuals in one
90-100%
subpopulation =
(b) extreme fluctuations in the number of mature individuals
IUCN (International Union for Conservation of Nature)
Criterion C
Points to remember:
• The population size threshold must be met before considering the
thresholds for subcriteria C1 or C2
• Subcriterion C1 is based on continuing decline at a specified rate
and over a very specific time period
• Subcriterion C2 is based on continuing decline at any, unspecified
rate, but the taxon must also meet the requirements for
subcriteria C2a or C2b
IUCN (International Union for Conservation of Nature)
Criterion D
Very small or restricted population
IUCN (International Union for Conservation of Nature)
Criterion D
Criterion D is split into D for the CR and EN categories; and D1 and
D2 for the VU category.
D. Total current
population size
estimated as:
CR
< 50 mature
individuals
EN
< 250 mature
individuals
NOTE: for the VU D2,
there should be a
plausible threat that is
likely to rapidly affect
the population.
D1. Total current
population size
estimated as:
VU
D2. The population
has a very restricted
AOO (typically <20
km²) or is known from
very few locations
< 1,000 mature
IUCN (International
Union for Conservation
of Nature)
(typically
≤5).
individuals
Use any of the criteria A-E
Critically Endangered
D. Very small or restricted population
Either:
Number of mature
individuals
< 50
Vulnerable
Endangered
< 250
D1.
< 1,000
AND / OR
VU D2. Restricted area of occupancy or number of
locations with a plausible future threat that could
drive the taxon to CR or EX in a very short time.
D2. typically:
AOO < 20 km² or
number of locations ≤ 5
IUCN (International Union for Conservation of Nature)
Criterion D
Points to remember:
• Criterion D has population size thresholds that apply to categories CR
and EN only
• Subcriteria D1 and D2 apply to the VU category only
• Subcriterion D2 should be used when a population has a very
restricted range such that it is prone to the effects of human activities
or stochastic events within a very short time period
• When using subcriterion D2, the most serious plausible threat to the
species should be stated in the assessment
• In subcriterion D2, the values for AOO and number of locations are
given as examples only
IUCN (International Union for Conservation of Nature)
Criterion E
Quantitative analysis
= oh ohh!
IUCN (International Union for Conservation of Nature)
Criterion E
Based on quantitative analysis showing a probability
of extinction in the wild is at least:
50%
20%
Critically
Endangered
Within 10 years
or 3 generations
Endangered
Within 20 years
or 5 generations
10%
Vulnerable
Within 100 years
Up to a maximum of 100 years in the future
IUCN (International Union for Conservation of Nature)
Use any of the criteria A-E
Critically Endangered
Endangered
 50% in 10 years or 3
generations (100 years
max)
 20% in 20 years or 5
generations (100 years
max)
Vulnerable
E. Quantitative analysis
Indicating the probability of
extinction in the wild to be:
 10% in 100
IUCN (International Union for Conservation of Nature)
RED LIST DOCUMENTATION
• All species in the Red List have supporting documentation
• Justifies the selected category and criteria
• Allows analysis of Red List data (information coded using
standard Classification Schemes)
•
•
•
•
•
•
Taxonomy including authority details
Common names
Red List Category and Criteria
Countries of occurrence
Map of distribution
Rationale for the assessment
(supporting the criteria used)
•
•
•
•
•
•
•
Names of assessors & contributors
Habitat preferences (text & codes)
Major Threats (text and codes)
Conservation Measures in place &
needed (text and codes)
Trade and Use
Citations list
IUCN
Union for Conservation
Reasons
for(International
any category
changes of Nature)
Thank you!
Questions?
IUCN (International Union for Conservation of Nature)