IUCN Red Listing Process Flashcards
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 naturalized population (or populations) well outside the past range
Critically Endangered (CR)
Considered to be facing an extremely high risk of extinction in the wild
Endangered (EN)
Considered to be facing a very high risk of extinction in the wild
Vulnerable (VU)
Considered to be facing a high risk of extinction in the wild
Near Threatened (NT)
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)
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.
Data Deficient (DD)
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
Not Evaluated (NE)
when it has not yet been evaluated against the criteria
Population
The total number of individuals of a given taxon across its global range
Population size
measured as the number of mature individuals only
Subpopulations
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
Individuals that are known, estimated or inferred to be capable of reproduction
Generation Length
The average age of parents of the current cohort
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.
Reduction
A decline in population size over the specified time period
Continuing decline
recent, current or projected future decline which is liable to continue unless remedial measures are taken
Extent of Occurrence
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
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).
Criteria
A: Population reduction
B: Geographic range + “threat”
C: Small population size and small decline
D: Very small restricted stable population
E: Quantitative analysis of risk
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
Criterion A
Based on any of the four criteria
A1: Population reduction in past and causes of decline understood and ceased. Reduction is reversible
A2: Population reduction in past and causes may not be understood or may not have ceased or reduction may not be reversible
A3: Population reduction expected in future
A4: Population reduction in past AND future
Criterion B
Based on either:
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
Criterion C
Based on small population size AND either C1 or C2
C1: Continuing decline in population size at a specified rate
C2: Continuing decline in population size at any unspecified rate AND either C2a or C2b:
a: very small subpopulations or most mature individuals are in one subpopulation
b: extreme fluctuations in number of mature individuals
Criterion D
D for CR and EN categories, and D1 and D2 for VU category
D: Total current population size estimated as < 50-250 mature individuals
D1: Total current population size estimates as < 1000 mature individuals
D2: The population has a very restricted AOO or is known from very few locations –> there should be a plausible threat that is likely to rapidly affect the population
