The
threatened species categories now used in Red Data
Books and Red Lists have been in place, with some
modification, for almost 30 years. Since their
introduction these categories have become widely
recognised internationally, and they are now used in
a whole range of publications and listings, produced
by IUCN as well as by numerous governmental and
non-governmental organisations. The Red Data Book
categories provide an easily and widely understood
method for highlighting those species under higher
extinction risk, so as to focus attention on
conservation measures designed to protect them.
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to see the threat categories
A
species is Critically Endangered
when it is facing an extremely high risk of
extinction in the wild in the immediate future, as
defined by any of the following criteria:
A)
Population Reduction.
B)
Extent of occurrence estimated to be less than 100
km2 or area of occupancy estimated to be less than 10
km2
C)
Population estimated to number less than 250 mature
individuals
D)
Population estimated to number less 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.
A taxon
is Endangered when it is not
Critically Endangered but is facing a very high risk
of extinction in the wild in the near future, as
defined by any of the following criteria (A to E):
A) Population
reduction
B) Extent of occurrence estimated to be less than
5000 km2 or area of occupancy estimated to be less
than 500 km2, and estimates indicating any two of the
following:
C) Population estimated to number less than 2500
mature individuals
D) Population estimated to number less 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.
A
species 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
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:
C) Population estimated to number less than 10,000
mature individuals
D) Population very small or restricted
E) Quantitative analysis showing the probability of
extinction in the wild is at least 10% within 100
years.
Information
obtained from http://www.redlist.org
