The Red Data Book

About:

Species judged as threatened are listed by various agencies as well as by some private organizations. The most cited of these lists is the Red Data Book.

• It is a loose-leaf volume of information on the status of many kinds of species. This volume is continually updated and is issued by International union for conservation of nature located in Morges, Switzerland.
• “Red” of course is symbolic of danger that the species both plants and animals presently experience throughout the globe.
• The red data book was first issued in 1966 by the IUCN’s special survival commission as a guide for formulation, preservation and management of species listed.
• In this book, information for endangered mammals and birds are more extensive than for other groups of animals and plants, coverage is also given to less prominent organisms facing extinction.
• The pink pages in this publication include the critically endangered species, as the status of species changes, new pages are sent to the subscribers..
• Green pages are used for those species that were formally endangered, but have now recovered to a point where they are no longer threatened. With passing time, the number of pink pages continues to increase. There are pitifully few green pages.

IUCN classification of conservation priority:

Extinct (EX):
A taxon is Extinct when there is no reasonable doubt that the last individual has died.

Extinct in 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)

A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria A to E for Critically Endangered (see Section V), and it is therefore considered to be facing an extremely high risk of extinction in the wild.

Criteria for Critically Endangered:

• Reduction of population ≥ 90% over the last 10 years.

• Population size estimated to number fewer than 50 mature individuals.
• Quantitative analysis showing the probability of extinction in the wild is at least 50% within 10 years.
• It is therefore considered to be facing an extremely high risk of extinction in the wild.

Endangered (EN):

A taxon is endangered when the best available evidence indicates that it meets any of the criteria A to E for Endangered, and it is therefore considered to be facing a very high risk of extinction in the wild.

Criteria for Endangered:

• Reduction in population ≥ 70% over the last 10 years 
• Population size estimated to number fewer than 250 mature individuals.
• Quantitative analysis showing the probability of extinction in the wild is at least 20% within 20 years or five generations, whichever is the longer.

• It is therefore considered to be facing an extremely high risk of extinction in the wild.

Vulnerable (VU):

A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.

Criteria for Vulnerable:

• Reduction in population ≥ 50% over the last 10 years 
• Population size estimated to number fewer than 10,000 mature individuals 
• Probability of extinction in the wild is at least 10% within 100 years, and
• It is therefore considered to be facing an extremely high risk of extinction in the wild.

 Near Threatned (NT):

A taxon is Near Threatened when it has been evaluated against the criteria but does not qualify for Critically Endangered, Endangered or Vulnerable now, but is close to qualifying for or is likely to qualify for a threatened category in the near future.

Least Concern (LC):
A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened.

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. Data deficient is therefore not a category of threat.

Not Evaluated (NE):
A taxon is Not Evaluated when it is has not yet been evaluated against the criteria.