IUCN Categories and Red Data List

IUCN stands for International Union for the Conservation of Nature and Natural Resources. It is an organization for nature conservation and the sustainable use of national resources. 

IUCN categories consist of those species that are at high risk of global extinction. This classification is based on population size, degree of population distribution and fragmentation, rate of decline, and area of geographical distribution. 

Based on these criteria, there are about nine IUCN categories under the IUCN Red List. 

Types of IUCN Categories

Extinct

The species that are extinct, with the clarity that the last one has also died. 

Extinct in the Wild

Species of endangered flora and fauna that are extinct in wild conditions but survive in cultivation and capacity. 

Threatened Species

This category includes those species that are critically endangered or vulnerable. They are assessed under certain criteria according to each species. They can be further categorized into three. 

• Critically endangered species that are at high risk of extinction in the wild in the near future. They must fulfil the following criteria to be called critically endangered.
  • Decline of ≥80-90% population
  • Population size ＜250 individuals.
  • Occurrence in ＜100 Km²
  • Area of occupancy less than 10 Km²
  • Extinction probability  ≥50% in 10 years or 3 generations.
• Endangered species are those with a risk of extinction.
  • Extinction probability is  ≥20% in 20 years or 5 generations.
  • Population decline  of 50-70%
  • Population size ＜2500 individuals
  • Area occupancy is ＜500 Km²
  • Occurrence in ＜5000 Km²
• Vulnerable species are those that are facing some risk of extinction at least 10% in the coming 100 years.
  • Reduced population by  ≥30-50%.
  • Population size ＜10,000 mature  individuals
  • Area occupancy is ＜2000 Km2
  • Occurrence in ＜20,000 Km2

Near Threatened Species

The species that do not qualify to be called as mentioned above but do not have an adequate number of individuals for a healthy population come under near threatened category. Those under this category will have to depend on the conservation programs for their survival for longer. 

Least Concern Species

If a taxon is evaluated against anything as the above categories, they do not come under the least concern category. They will be abundant and widespread across the world or in their native areas. 

IUCN Red List of Threatened Species

The IUCN Red List is one of the most comprehensive categorizations in the world for global conservation status for flora and fauna. A set of criteria evaluates and determines the category of each species as well as the subspecies. This is relevant for all species across the world.

The IUCN Red List is based on the assessment of the risk of extinction of the species, including the risks of the past, present, and near future. There is a standardized process for the assessment, documentation, management of data, review by experts, and justification of each inclusion. 

All species that are under the critically endangered, endangered, and vulnerable categories are collectively termed threatened.

References

• Shukla, R.S. and Chandel, P.S. (2001) Plant Ecology. S. Chand and Company Ltd., New Delhi.
• Verma, P.S., Agarwal, V.K. (1999). Cell biology, Genetics, Molecular Biology, Evolution, and Ecology. New Delhi: S.Chand Co.(Pvt) Ltd.
• IUCN Red List Categories and Criteria

Additional Topics

• Endangered Flora