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 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 20% 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.

2) A reduction of at least 20%, projected or
suspected to be met within the next ten years or
three generations, whichever is the longer,
based on (and specifying) any of (b), (c), (d) or (e)
above.

B) Extent of occurrence estimated to be less than
20,000 km2 or area of occupancy estimated to be
less than 2000 km2, and estimates indicating any
two of the following:

1) Severely fragmented or known to exist at no
more than ten locations.

2) Continuing decline, inferred, observed 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.

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.

C) Population estimated to number less than 10,000
mature individuals and either:

1) An estimated continuing decline of at least 10%
within 10 years or 3 generations, 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 1000 mature
individuals)
b) all individuals are in a single subpopulation.

D) Population very small or restricted in the form of
either of the following:

1) Population estimated to number less than 1000
mature individuals.

2) Population is characterised by an acute
restriction in its area of occupancy (typically less
than 100 km2) or in the number of locations
(typically less than 5). Such a taxon would thus
be prone to the effects of human activities (or
stochastic events whose impact is increased by
human activities) within a very short period of
time in an unforeseeable future, and is thus
capable of becoming Critically Endangered or
even Extinct in a very short period.

E) Quantitative analysis showing the probability of
extinction in the wild is at least 10% within 100
years.

Alternative form for Vulnerable : VU.