Introduction to the IUCN Red Listing Process

Introduction to the IUCN
Red Listing Process
IUCN (International Union for Conservation of Nature)

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
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)

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.
Least Concern (LC)
Photo © H. Fraga
Macaronesian Laurel, Laurus azorica
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.
Photo © Caroline Pollock
IUCN (International Union for Conservation of Nature)
Olive Baboon, Papio anumbis

Data Deficient (DD)
Tree Tomato
Solanum [Cyphomandra] betacea
Not Evaluated (NE)
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)

IUCN (International Union for Conservation of Nature)

IUCN (International Union for Conservation of Nature)

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
IUCN (International Union for Conservation of Nature)

IUCN (International Union for Conservation of Nature)

IUCN (International Union for Conservation of Nature)

Reduction is a decline in population
size of at least the % stated in criterion
A over the specified time period.
Population
Size
Time
IUCN (International Union for Conservation of Nature)

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.
IUCN (International Union for Conservation of Nature)

IUCN (International Union for Conservation of Nature)

Invasive
species
2 locations
IUCN (International Union for Conservation of Nature)

Pollution
4 locations
IUCN (International Union for Conservation of Nature)

4-5
locations
Pollution
IUCN (International Union for Conservation of Nature)

The IUCN Red List Criteria
IUCN (International Union for Conservation of Nature)

A
CRITERIA
Nature of the Criteria
Population
reduction
THREATENED
CATEGORIES
B
Restricted
geographic range
Critically Endangered (CR)
C
Small population
size & decline
Quantitative
thresholds
Endangered (EN)
D
E
Very small or
restricted
population
Quantitative
analysis
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)

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 criteria:
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)

Criterion A
Managed harvest species
(e.g., fisheries)
Taxa that are the target of large-scale harvesting may show a decline in population size due
to intentional management actions. Such taxa could be assigned a threatened status under
criterion A.
Concern has been expressed that such a listing might not reflect extinction risk, especially if
the decline is a consequence of a management plan designed to maximize sustainable
yield from a fishery.
BUT, if the fishery is managed effectively, although it currently shows symptoms consistent
with endangerment, the population will eventually stabilize at a target level and the decline
will end, such that the taxon would then no longer qualify for listing. If declines continued,
there would be good reason for concern, and the listing would still apply.
Taxa that are targeted by sustainably managed fisheries should be assessed under criterion
A1, where the higher thresholds make it less likely that they will be classified as threatened.
IUCN (International Union for Conservation of Nature)

Criterion A1
past reduction & causes
understood & ceased &
reduction is reversible
Present
Last 10 years or 3 generations
(whichever is longer)
Criterion A2
past reduction & causes
may not be understood
or may not have ceased
or reduction may not be
reversible
Present IUCN (International Union for Conservation of Nature)
Last 10 years or 3 generations
(whichever is longer)

Sub-criterion A3
future decline
Present
Next 10 years or 3 generations
(whichever is longer up to a maximum of 100
years)
Sub-criterion A4
past & future
Present
10 years or 3 generations IUCN (International Union for Conservation of Nature)
(whichever is longer, up to a maximim of 100 years in the future)
including some time in the past AND in the future

Sub-criterion A4
past & future: “shifting time window”
10 years 10 / 3 years generations 10 / 3 years generations / 3 generations
6.65 years 3.3 / 2 years 1.5 / 1 3.356.6 years years / / 11.5
/ 2
generations generation
generations
Present
IUCN (International Union for Conservation of Nature)

For ALL the criteria (A1–A4), rate of population
reduction should be based on any of:
(a) Direct observation (not for sub-criterion 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)

Criterion A
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 sub-criteria:
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
Extent of occurrence
estimated to be:
Subcriterion B2
Area of occupancy
estimated to be:
CR
EN
VU
IUCN (International Union for Conservation of Nature)

Criterion B
AND at least TWO of a, b or c:
CR
EN
a. Severely
fragmented or
# locations:
VU ≤ 10
b. Continuing decline in
any of the following:
(i) EOO
(ii) AOO
(iii) Area, extent and/or
quality of habitat
(iv) # locations or
subpopulations
(v) # mature individuals
c. Extreme fluctuation in
any of the following:
(i) EOO
(ii) AOO
(iii) # locations or
subpopulations
(iv) # mature individuals
IUCN (International Union for Conservation of Nature)

Criterion B
Points to remember:
• Subcriterion B1 is based on extent of occurrence, while subcriterion
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. (fragmentation, decline, fluctuation)
• 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)

Popondetta Blue-eye (
Pseudomugil connieae)
Vulnerable B1ab(iii)
Justification:
Assessed as Vulnerable due to its restricted extent of occurrence,
which is 15,927 km². This species occurs in only three locations, (three
river systems). Two of these locations are threatened by urban
encroachment. In addition, P. connieae is threatened by a continuing
decline in habitat quality, due to logging, and an increase in agriculture
and urbanization in the region of Popondetta.
IUCN (International Union for Conservation of Nature)

Subcriterion B1
Extent of occurrence
estimated to be:
Subcriterion B2
Area of occupancy
estimated to be:
CR
EN
VU
IUCN (International Union for Conservation of Nature)

AND at least TWO of a, b or c:
CR
EN
a. Severely
fragmented or
# locations:
VU ≤ 10
b. Continuing decline in
any of the following:
(i) EOO
(ii) AOO
(iii) Area, extent and/or
quality of habitat
(iv) # locations or
subpopulations
(v) # mature individuals
c. Extreme fluctuation in
any of the following:
(i) EOO
(ii) AOO
(iii) # locations or
subpopulations
(iv) # mature individuals
IUCN (International Union for Conservation of Nature)