IUCN - The World Conversation Union

Biodiversity loss is one of the world's most pressing crises and there is growing global concern about the status of the biological resources on which so much of human life depends. It has been estimated that the current species extinction rate is between 1,000 and 10,000 times higher than it would naturally be.

Many species are declining to critical population levels, important habitats are being destroyed, fragmented, and degraded, and ecosystems are being destabilised through climate change, pollution, invasive species, and direct human impacts. At the same time, there is also growing awareness of how biodiversity supports livelihoods, allows sustainable development and fosters co-operation between nations. This awareness is generated through products such as the IUCN Red List of Threatened Species.

Governments, the private sector, multilateral agencies responsible for natural resource use, and environmental treaties all need access to the latest information on biodiversity when making environment-related decisions. Information about species and ecosystems is essential for moving towards more sustainable use of our natural resources.

The IUCN Red List System was first conceived in 1963 and set a standard for species listing and conservation assessment efforts. For more than 30 years the Species Survival Commission has been evaluating the conservation status of species and subspecies on a global scale - highlighting those threatened with extinction and promoting their conservation.

Over time, however, IUCN recognised that a more objective and scientific system for determining threat status was needed, one that drew on advances in the science of conservation biology and other disciplines. There was also a need for a more accurate system for use at the national and regional level. The IUCN Red List Categories evolved over a four-year period through extensive consultation and testing with more than 800 SSC members, and the wider scientific community. The more precise and quantitative Red List Categories and Criteria were adopted by IUCN in 1994.

In 1988 all bird species were evaluated, and in the 1996 IUCN Red List of Threatened Animals the conservation status of every mammal species in the world was assessed for the first time. These were major milestones in conservation because not only was the overall status of mammals and birds determined, but a baseline was established from which to monitor future trends. For the 1996 list 5,205 species were evaluated resulting in 25% of all mammals and 11% of all birds being listed as threatened.

The system has since undergone further intense review and has been refined to ensure the highest standards of documentation (supporting information), information management, training, and scientific credibility.

The IUCN Red List Categories and Criteria are leading IUCN in new directions that will allow sophisticated biodiversity analyses, which will contribute to scientific discovery and to political policies related to conservation at local, national, and regional levels.

“Red List Indices" have been produced which chart overall changes in the threat status of the world's birds and amphibians, the two groups that have been completely assessed. These are based on the number of species that moved between categories as a result of genuine changes in threat status (excluding moves resulting form improved knowledge or taxonomic changes).

The IUCN Red List Programme will improve the taxonomic coverage of the Red List Indices in the coming years as they are central to monitoring the progress of global efforts to reduce biodiversity loss.

The IUCN Red List is the world's most comprehensive inventory of the global conservation status of plant and animal species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity.

The overall aim of the Red List is to convey the urgency and scale of conservation problems to the public and policy makers, and to motivate the global community to try to reduce species extinctions.

The Biodiversity Assessments Sub-Committee (BASC) oversees and guides the Species Survival Commission’s work on biodiversity assessments BASC terms of reference ( 30KB). This includes having responsibility for the IUCN Red List. The BASC reports to the SSC Steering Committee. Much of the work involved in producing and maintaining the IUCN Red List is technical in nature and several working groups have been formed within the BASC to carry out this work:

• Standards and Petitions Working Group (SPWG): The SPWG is responsible for ensuring the quality and standard of the IUCN Red List, focusing on the correct use of the IUCN Red List Categories and Criteria. This working group developed and regularly updates the Guidelines for using the IUCN Red List Categories and Criteria, and is responsible for making final decisions over formal petitions against listings on the IUCN Red List. SPWG terms of reference ( 42KB).
• National Red List Working Group (NRLWG): The NRLWG is responsible for overseeing the use of the IUCN Red List Categories and Criteria at the national level, and for building linkages between the IUCN Red List and species assessment processes at national levels. NRLWG terms of reference ( 27KB).
• Biodiversity Assessment Users Working Group (UWG): The UWG is responsible for ensuring consistency in application of the IUCN Red List Categories and Criteria. In particular, the UWG seeks to ensure that the SSC’s major global and regional biodiversity assessment projects are implemented in a similar manner. UWG terms of reference ( 26KB).
• Red List Index Working Group (RLIWG): The RLIWG is responsible for developing the IUCN Red List Index as a tool for monitoring changes in the status of biodiversity at the species level. RLI terms of reference ( 27KB).
• Classification Schemes Working Group (CSWG): The CSWG is responsible for defining and proposing changes to the IUCN Classification Schemes that will be needed in order to carry out new analyses and produce agreed priority products by 2008. CSWG terms of reference ( 22KB).

In order to significantly increase the number of species assessments for the Red List, a Red List partnership has been formed comprising IUCN and its Species Survival Commission, BirdLife International, Conservation International's Center for Applied Biodiversity Science, and NatureServe. Red list partnership.

The Red List is used by government agencies, wildlife departments, conservation-related non-governmental organizations (NGOs), natural resource planners, educational organizations, and many others interested in reversing, or at least halting the decline in biodiversity.

• Draws attention to the magnitude and importance of threatened biodiversity
  

• Identifies and documents those species most in need of conservation action

• Provides a global index of the decline of biodiversity

• Establishes a baseline from which to monitor the future status of species

• Provides information to help establish conservation priorities at the local level and guide conservation actionHelps influence national and international policy, and provides information to international agreements such as the Convention on Biological Diversity (CBD) and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

• How threatened is a particular species?
• What are the threats to a species?
• How many threatened species occur in a given country?
• How many known extinctions have there been?

There are nine categories in the IUCN Red List system: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient, and Not Evaluated. Classification into the categories for species threatened with extinction (Vulnerable, Endangered, and Critically Endangered) is through a set of five quantitative criteria that form the heart of the system. These criteria are based on biological factors related to extinction risk and include: rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation.

For more detail see the IUCN Red List Categories and Criteria version 3.1. and the IUCN Red List Process.

EXTINCT (EX)
A taxon is Extinct when there is no reasonable doubt that the last individual has died. A taxon is presumed Extinct when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form.

EXTINCT IN THE 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. A taxon is presumed Extinct in the Wild when exhaustive surveys in known and/or expected habitat, at appropriate times (diurnal, seasonal, annual), throughout its historic range have failed to record an individual. Surveys should be over a time frame appropriate to the taxon's life cycle and life form.

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 Red List Categories and Criteria booklet for details) and 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 (see Red List Categories and Criteria booklet for details), and it is therefore considered to be facing a very 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 (see Red List Categories and Criteria booklet for details), and it is therefore considered to be facing a high risk of extinction in the wild.

NEAR THREATENED (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. Widespread and abundant taxa are included in this category.

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. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking. Data Deficient is therefore not a category of threat. 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. It is important to make positive use of whatever data are available. In many cases great care should be exercised in choosing between DD and a threatened status. If the range of a taxon is suspected to be relatively circumscribed, and a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified.

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

The Red List is produced by the IUCN Species Survival Commission (SSC) - a network of some 7,000 species experts working in almost every country in the world, and data from a number of partner organizations. Collectively, this network holds what is probably the most complete scientific knowledge base on the biology and current conservation status of species.

All data underlying the Red List will eventually be maintained in a series of databases that make up the SSC's emerging Species Information Service. This is a major initiative that aims to make the vast amount of information held by the SSC network easily and quickly accessible to users around the world.

To improve the previous ad hoc process of listing species, Red List Authorities (RLAs) are being established for all taxonomic groups included on the Red List RLA Terms of Reference ( 85 KB). In most cases, the Authority is the SSC Specialist Group responsible for a species, a group of species, or a geographic area. BirdLife International has been designated as the RLA for birds and will liaise with the bird Specialist Groups and Wetlands International, where necessary. No new species will be added to the Red List until it has been evaluated by an appointed RLA. All species on the list must be re-evaluated at least once every 10 years. Full list of current Red list Authorities.

Taxonomic standards have been adopted and all species on the IUCN Red List should have conformed to these by the year 2003. Adherence to the documentation and taxonomic standards will bring greater credibility and transparency to listings, and allow better analyses of the findings.

Status assessments included in the IUCN Red List are also open to formal challenge (see Red List petitions process). Petitions may be made against particular listings but only on the basis of the Red List Categories and Criteria and in reference to supporting documentation accompanying the listing. Petitions may not be made for political or economic reasons.

There is increasing demand for training from all regions of the world as countries step up efforts to assess their biodiversity and use the Red List as a basis for conservation action. SSC staff run workshops around the world on how to apply the criteria at a regional level. In September 2003, SSC published the Guidelines for Application of IUCN Red List Criteria at Regional Levels which are available on this site in English, French and Spanish in PDF.