IUCN Red List of Threatened Species

Introduction

The IUCN Red List of Threatened Species™ is widely recognized as the most comprehensive, objective global approach for evaluating the conservation status of plant and animal species.

The IUCN Red List assesses the extinction risk of species. Assessments of all mammals, birds, amphibians, sharks, reef-building corals, cycads and conifers have been completed. Efforts are underway to assess all reptiles, fishes and selected groups of plants and invertebrates. This sample indicates how life on Earth is faring, how little is known, and how urgent the need is to assess more species. In this way, The IUCN Red List is becoming The Barometer of Life.

The IUCN Red List partnership

The IUCN Red List is produced and managed by the IUCN Global Species Programme and the Species Survival Commission (SSC). The IUCN Red List Partnership consists of members and partners of IUCN who are making a particularly significant contribution to The IUCN Red List of Threatened Species ™. This takes the form of technical or financial support or both. The Partnership currently consists of:

· BirdLife International

· Botanic Gardens Conservation International (BGCI)

· Conservation International

· Sapienza Università di Roma

· NatureServe

· Royal Botanic Gardens Kew

· Texas A&M University

· Wildscreen

· Zoological Society of London

A Brief History of the IUCN Red List

· 1963 - the IUCN Red List System was first conceived

· 1988 – all bird species were evaluated

· 1994 – a more precise and quantitative Red List Categories and Criteria were adopted

· 1996 – all mammal species were evaluated

The Categories

Extinct	EX
Extinct in the Wild	EW
Critically Endangered	CR
Endangered	EN
Vulnerable	VU
Near Threatened	NT
Least Concern	LC
Data Deficient	DD
Not Evaluated	NE

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 is know 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 survived 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 meet any of the criteria for Critically Endangered, and it is therefore considered to be facing an extremely high risk of extinction in the wild.

A. Reduction in population size base on any of the following :

1. An observed, estimated, inferred or suspected population size reduction of ³90% 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, based on (and specifying) any of the following :

(a) direct observation

(b) an index of abundance appropriate to the taxon

(c) a decline in area of occupancy, extent of occurrence and/or quality of habitat

(d) actual or potential levels of exploitation

(e) the effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.

2. An observed, estimated, inferred or suspected population size reduction of ³80% 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 base on (and specifying) any of (a) to (e) under A1.

3. A population size reduction of ³80%, projected or suspected to be met within the next 10 years or three generations, whichever is the longer (up to a maximum of 100 years), based on (and specifying) any of (b) to (e) under A1.

4. An observed, estimated, inferred, projected or suspected population size reduction of ³80% over any 10 year or three generation period, whichever is longer (up to a maximum of 100 years in the future), where the time period must include both the past and the future, and where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.

B. Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of occupancy) OR both :

         

1. Extent of occurrence estimated to be less than 100km² , and estimates indicating at least two of (a) to (c) :

(a) severely fragmented or known to exist at only a single location.

(b) continuing decline, observed, inferred or projected, in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)area, extent and/or quality of habitat

          (iv) number of locations or subpopulations

          (v) number of mature individuals.

(c) extreme fluctuations in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)number of locations or subpopulations

          (iv) number of mature individuals.

         

2. Area of occupancy estimated to be less than 10km² , and estimate indicating at least two of 1(a) to 1(c).

C. Population size estimated to number fewer than 250 mature individuals and either :

1. an estimated continuing decline of at least 25% within three years or one generation, whichever is longer, (up to a maximum of 100 years in the future) OR

2. a continuing decline, observed, projected, or inferred, in numbers of mature individual AND at least one of the following :

(a) population structure in the form of the following :

(i)  no subpopulation estimated to contain more than 50 mature  individuals, OR

          (ii) at least 90% of mature individuals in one subpopulation.

(b) extreme fluctuations in number of mature individuals.

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).

Endangered (EN)

A taxon is Endangered when the best available evidence indicates that it meet any of the criteria for Endangered , and it is therefore considered to be facing an extremely high risk of extinction in the wild.

A. Reduction in population size base on any of the following :

1. An observed, estimated, inferred or suspected population size reduction of ³70% 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, based on (and specifying) any of the following :

(a) direct observation

(b) an index of abundance appropriate to the taxon

(c) a decline in area of occupancy, extent of occurrence and/or quality of habitat

(d) actual or potential levels of exploitation

(e) the effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.

2. An observed, estimated, inferred or suspected population size reduction of ³50% 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 base on (and specifying) any of (a) to (e) under A1.

3. A population size reduction of ³50%, projected or suspected to be met within the next 10 years or three generations, whichever is the longer (up to a maximum of 100 years), based on (and specifying) any of (b) to (e) under A1.

4. An observed, estimated, inferred, projected or suspected population size reduction of ³50% over any 10 year or three generation period, whichever is longer (up to a maximum of 100 years in the future), where the time period must include both the past and the future, and where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.

B. Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of occupancy) OR both :

         

1. Extent of occurrence estimated to be less than 5,000km² , and estimates indicating at least two of (a) to (c) :

(a) severely fragmented or known to exist at more than five locations.

(b) continuing decline, observed, inferred or projected, in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)area, extent and/or quality of habitat

          (iv) number of locations or subpopulations

          (v) number of mature individuals.

(c) extreme fluctuations in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)number of locations or subpopulations

          (iv) number of mature individuals.

         

2. Area of occupancy estimated to be less than 500km² , and estimate indicating at least two of 1(a) to 1(c).

C. Population size estimated to number fewer than 2,500 mature individuals and either :

1. an estimated continuing decline of at least 20% within five years or two generation, whichever is longer, (up to a maximum of 100 years in the future) OR

2. a continuing decline, observed, projected, or inferred, in numbers of mature individual AND at least one of the following :

(a) population structure in the form of the following :

(i)  no subpopulation estimated to contain more than 250 mature  individuals, OR

          (ii) at least 90% of mature individuals in one subpopulation.

(b) extreme fluctuations in number of mature individuals.

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 (up to a maximum of 100 years).

Vunerable (VU)             

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

A. Reduction in population size base on any of the following :

1. An observed, estimated, inferred or suspected population size reduction of ³50% 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, based on (and specifying) any of the following :

(a) direct observation

(b) an index of abundance appropriate to the taxon

(c) a decline in area of occupancy, extent of occurrence and/or quality of habitat

(d) actual or potential levels of exploitation

(e) the effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.

2. An observed, estimated, inferred or suspected population size reduction of ³30% 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 base on (and specifying) any of (a) to (e) under A1.

3. A population size reduction of ³30%, projected or suspected to be met within the next 10 years or three generations, whichever is the longer (up to a maximum of 100 years), based on (and specifying) any of (b) to (e) under A1.

4. An observed, estimated, inferred, projected or suspected population size reduction of ³30% over any 10 year or three generation period, whichever is longer (up to a maximum of 100 years in the future), where the time period must include both the past and the future, and where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on (and specifying) and of (a) to (e) under A1.

B. Geographic range in the form of either B1 (extend of occurrence) OR B2 (area of occupancy) OR both :

         

1. Extent of occurrence estimated to be less than 20,000km² , and estimates indicating at least two of (a) to (c) :

(a) severely fragmented or known to exist at more than 10 locations.

(b) continuing decline, observed, inferred or projected, in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)area, extent and/or quality of habitat

          (iv) number of locations or subpopulations

          (v) number of mature individuals.

(c) extreme fluctuations in any of the following :

          (i)  extent of occurrence

          (ii) area of occupancy

          (iii)number of locations or subpopulations

          (iv) number of mature individuals.

         

2. Area of occupancy estimated to be less than 2,000km² , and estimate indicating at least two of 1(a) to 1(c).

C. Population size estimated to number fewer than 10,000 mature individuals and either :

1. an estimated continuing decline of at least 10% within 10 years or three generations, whichever is longer, (up to a maximum of 100 years in the future) OR

2. a continuing decline, observed, projected, or inferred, in numbers of mature individual AND at least one of the following :

(a) population structure in the form of the following :

(i)  no subpopulation estimated to contain more than 1,000 mature  individuals, OR

          (ii) all mature individuals in one subpopulation.

(b) extreme fluctuations in number of mature individuals.

D. Population very small or restricted in the form of either of the following :

1. population size estimated to number fewer than 1,000 mature individuals.

2. population with a very restricted area of occupancy (typically less than 20km²) or number of locations (typically five or fewer) such that is prone to the effects of human activities or stochastic events within a very short time period in an uncertain future, and is thus capable of becoming Critically Endangered or ever Extinct in a very short time period.       

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

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 evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened.  Widespread and abundant taxa are included in the 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 studies, and its biology well know, 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 has not yet been evaluated against the criteria.