What is ‘Conservation Status’ and ‘IUCN Red List’?

Hawaiian-Monk-Seal             Endangered Hawaiian monk seal

We’re all familiar with the terms ‘Endangered’, and ‘Threatened’ when referring to species under threat from extinction. But the process behind these categorizations and so on, and just how important these species are for biodiversity conservation, is a bit of a mystery to most of us. This process of categorization or Conservation Status as it is called as is extremely complicated and difficult one since it involves collection and classification of a massive amount of information.  The authenticity of information is also extremely difficult to verify.  It is impossible to verify, for example, Indian government’s claim of the increase in the number of tigers in Indian wild.  The conservation status of species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. Many factors are taken into account when assessing the conservation status of a species: not merely the number remaining, but the overall increase or decrease in the population over time, breeding success rates, known threats, climate changes and so on.

Various systems of conservation status exist and are in use at international, multi-country, national and local levels as well as for consumer use. While there are local, national and regional lists of threatened species, it’s the internationally-recognized, global list that has the most influence on biodiversity conservation worldwide.

The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN provides public, private and non-governmental organizations with the knowledge and tools that enable human progress, economic development and nature conservation to take place together.


The IUCN Red List of Threatened Species is the best known worldwide conservation status listing and ranking system.  IUCN Red List classifies species into nine groups set through criteria such as rate of decline, population size, an area of geographic distribution, and degree of population and distribution fragmentation.  It is widely recognized as the most comprehensive, objective global approach for evaluating the conservation status of plant and animal species. From its small beginning, The IUCN Red List has grown in size and complexity and now plays an increasingly prominent role in guiding conservation activities of governments, NGOs, and scientific institutions and has become a world standard.

The IUCN Red List of Threatened Species provides taxonomic, conservation status and distribution information on plants, fungi, and animals that have been globally evaluated using the IUCN Red List Categories and Criteria. This system is designed to determine the relative risk of extinction, and the primary purpose of the IUCN Red List is to catalog and highlight those plants and animals that are facing a higher risk of global extinction (i.e., those listed as Critically Endangered, Endangered and Vulnerable). The IUCN Red List also includes information on plants, fungi, and animals that are categorized as Extinct or Extinct in the Wild; on taxa that cannot be evaluated because of insufficient information (i.e., are Data Deficient); and on plants, fungi and animals that are either close to meeting the threatened thresholds or that would be threatened were it not for an ongoing taxon-specific conservation programme (i.e., are Near Threatened).




A representation of the relationships between the categories is shown in above figure.

ExtictEXTINCT (EX) – A taxon (species or subspecies or family or class etc.) is ‘Extinct’ when there is no reasonable doubt that the last individual has died. The species or taxon is presumed ‘Extinct’ when exhaustive surveys in known and expected habitat have failed to record the existence of the individual.

Extinct in wildEXTINCT IN THE WILD (EW) – A taxon (species or subspecies or family or class etc.) is ‘Extinct in the Wild’ when it is known only to survive in cultivation, in captivity or as a naturalized population. The species is presumed ‘Extinct in the wild’ when exhaustive surveys in known and expected habitat, at appropriate times have failed to record the individual.

Critically endangeredCRITICALLY ENDANGERED (CR) – A taxon is ‘Critically Endangered’ when the best available evidence indicates that it faces an extremely high risk of extinction in the wild.

ENENDANGERED (EN) – A taxon is ‘Endangered’ when the best available evidence indicates that it faces a high risk of extinction in the wild.

VulnerableVULNERABLE (VU) – A taxon is ‘Vulnerable’ when the best available evidence indicates that it faces a risk of extinction in the wild.

NTNEAR THREATENED (NT) – A taxon is ‘Near Threatened’ when it has been evaluated against the criteria is close to qualifying for a threatened category shortly.

LCLEAST CONCERN (LC) – A taxon is ‘Least Concern’ when it has been evaluated against the criteria and does not qualify for any of the above rules. Widespread and abundant of species are included in this category.

DATA DEFICIENT (DD) & NOT EVALUATED (NE) – 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 population status. Listing of taxa in this category indicates that more information is required and acknowledges the possibility that future research will show that threatened classification is appropriate.  A taxon is ‘Not Evaluated’ when it has not yet been evaluated against the criteria.


Consumer guides – Consumer guides do not depict Conservation Status directly but advise consumers to have environmental consideration before dealing in various commodities which originate from natural resources and which are fearing extinction.  Some consumer guides for seafood, such as Seafood Watch, divide fish and other sea creatures into three categories, analogous to conservation status categories: Red (“say no” or “avoid”); Yellow or orange (“think twice”, “good alternatives” or “some concerns”); Green (“best seafood choices”).  The categories do not merely reflect the imperilment of individual species, but also consider the environmental impacts of how and where they are fished, such as through bycatch or ocean bottom trawlers. Often groups of species are assessed rather than individual species (e.g., squid, prawns).  The Marine Conservation Society has five levels of ratings for seafood species, as displayed on their FishOnline website.


References –

Wikipedia; BBC Earth; IUCN; Seafood Watch / Images courtesy – IUCN site.


Milind Joshi


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