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UPSC IAS Prelims : Environment and Ecology : IUCN Red List Categories and Criteria

Aug 5, 2015 11:50 IST

    Union Public Service Commission (UPSC) had merged Civil Services Exam (Popularly known as IAS Exam) with Indian Forest Service Exam at Preliminary stage in 2013. This decision increased manifold weightage of Environment and Ecology at Preliminary Examination of Civil Services. Civil Service Preliminary Examination have always questions on IUCN, IUCN Red List and its categories. Jagranjosh has systematically provided detailed idea about IUCN Red List categories and its criteria. This would benefit aspirant to know basics.

    IUCN Red List Categories

    IUCN has classified species into categories of Extinct, Extinct in wild, Critically Endangered, Endangered, Vulnerable, etc based on data collected across the world. IUCN has a Red List which provides a systematic list of plants and animals into various categories.

    Structure of Categories has been shown below: (Courtsey : IUCN)


     
    Definition of Categories:

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

    2. 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.

    3. 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:
    A.  Reduction in population size:
    1. Reduction of population ≥ 90% over the last 10 years or three generations, whichever is the longer, where the causes of the reduction are clearly reversible AND understood AND ceased.
    2. Reduction of population ≥ 80% over the last 10 years or three generations, whichever is the longer, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible.

    B. Geographic range in the form of either B1 (extent of occurrence) OR B2 (area of occupancy):
    B.1. Extent of occurrence estimated to be less than 100 km2, and estimates indicating severely fragmented or known to exist at only a single location.
    B.2. Area of occupancy estimated to be less than 10 km2, and severely fragmented or known to exist at only a single location.

    C. Population size estimated to number fewer than 250 mature individuals and an estimated continuing decline of at least 25% within three years or one generation, whichever is longer.

    D. Population size estimated to number fewer 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 (up to a maximum of 100 years).

    4. 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:

    A. Reduction in population size based on any of the following:
    1. Reduction in population ≥ 70% over the last 10 years or three generations, whichever is the longer, where the causes of the reduction are clearly reversible AND understood AND ceased.
    2. An observed, estimated, inferred or suspected population size reduction of ≥ 50% over the last 10 years or three generations, whichever is the longer, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible.

    B. Geographic range in the form of either B1 (extent of occurrence) OR B2 (area of occupancy) OR both:
    B.1. Extent of occurrence estimated to be less than 5000 km2, and severely fragmented or known to exist at no more than five locations.
    B.2. Area of occupancy estimated to be less than 500 km2, and severely fragmented or known to exist at no more than five locations.

    C. Population size estimated to number fewer than 2500 mature individuals and an estimated continuing decline of at least 20% within five years or two generations, whichever is longer.

    D. Population size estimated to number fewer 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.

    5. 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:
    A. Reduction in population size based on any of the following:
    1. Reduction in population ≥ 50% over the last 10 years or three generations, whichever is the longer, where the causes of the reduction are: clearly reversible AND understood AND ceased.
    2. Reduction of population ≥ 30% over the last 10 years or three generations, whichever is the longer, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible.

    B. Geographic range in the form of either B1 (extent of occurrence) OR B2 (area of occupancy) OR both:
    B.1. Extent of occurrence estimated to be less than 20,000 km2, and severely fragmented or known to exist at no more than 10 locations.
    B.2. Area of occupancy estimated to be less than 2000 km2, and estimates indicating severely fragmented or known to exist at no more than 10 locations.

    C. Population size estimated to number fewer than 10,000 mature individuals and an estimated continuing decline of at least 10% within 10 years or three generations, whichever is longer.

    D. Population size estimated to number fewer than 1000 mature individuals.

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

    6. 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.

    7. 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.

    8. 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.

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

    To study more about Environment and Ecology, click link given below:
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