UPSC MainsBOTANY-PAPER-II201410 Marks
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Q16.

IUCN classification of extinction risks

How to Approach

This question requires a detailed understanding of the IUCN Red List categories and criteria for assessing extinction risk. The answer should begin with defining the IUCN and its Red List, then systematically explain each category of threat, including the subcategories within 'Threatened' (Vulnerable, Endangered, Critically Endangered). Illustrative examples of species falling under each category should be provided. The answer should also briefly touch upon the factors considered while classifying species. A tabular representation of the categories would be beneficial.

Model Answer

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Introduction

The International Union for Conservation of Nature (IUCN) is a global authority on the status of the natural world and the measures needed to safeguard it. Established in 1948, it plays a crucial role in environmental conservation and sustainable development. A cornerstone of IUCN’s work is the Red List of Threatened Species, a comprehensive inventory of the global conservation status of biological species. This classification system, based on rigorous criteria, assesses the extinction risk of thousands of species, providing a vital tool for prioritizing conservation efforts and informing policy decisions. Understanding the IUCN classification is paramount for effective biodiversity conservation.

IUCN Red List Categories

The IUCN Red List categorizes species’ extinction risk using a hierarchical system. These categories range from ‘Least Concern’ to ‘Extinct’. The assessment process considers factors like population size, range, rate of decline, and threats to survival.

1. Extinct (EX)

Species are placed in this category when there is no reasonable doubt that the last individual has died. This is further divided into:

  • Extinct in the Wild (EW): Species known only to survive in captivity, cultivation, or as naturalized populations far outside its past range. Example: Przewalski’s Horse (successfully reintroduced).

2. Threatened

This category includes species facing a high risk of extinction. It is further subdivided into:

  • Critically Endangered (CR): Facing an extremely high risk of extinction in the wild. Meets any of the quantitative criteria for CR. Example: Amur Leopard (estimated <100 individuals remaining).
  • Endangered (EN): Facing a very high risk of extinction in the wild. Meets any of the quantitative criteria for EN. Example: Black Rhino (population recovering but still endangered).
  • Vulnerable (VU): Facing a high risk of extinction in the wild. Meets any of the quantitative criteria for VU. Example: Giant Panda (downlisted from Endangered to Vulnerable in 2016 due to conservation efforts).

3. Near Threatened (NT)

Species close to qualifying for or likely to qualify for a threatened category in the near future. Example: African Elephant (facing threats from poaching and habitat loss).

4. Least Concern (LC)

Species evaluated with a low risk of extinction. These species are not currently threatened, but their status should be monitored. Example: Brown Rat.

5. Data Deficient (DD)

Species for which there is inadequate information to make a direct, or informed assessment of its risk of extinction. More information is needed. Example: Many deep-sea fish species.

6. Not Evaluated (NE)

Species that have not yet been assessed by the IUCN.

Quantitative Criteria for Threatened Categories

The IUCN uses specific quantitative criteria to determine the threatened status. These criteria relate to population size reduction, geographic range, population size, and population fluctuations. For example, a species can be classified as Vulnerable if its population has declined by more than 30% over the last three generations.

Category Population Reduction (%) Geographic Range (Area of Occupancy) Population Size
Critically Endangered ≥90% over 3 generations <100 km² <250 mature individuals
Endangered ≥70% over 3 generations <500 km² <2,500 mature individuals
Vulnerable ≥30% over 3 generations <2,000 km² <10,000 mature individuals

Factors considered during classification: Habitat loss, climate change, poaching, invasive species, pollution, and disease are all considered when assessing a species’ risk of extinction.

Conclusion

The IUCN Red List is an indispensable tool for conservation planning and action. By providing a standardized and scientifically rigorous assessment of extinction risk, it enables prioritization of conservation efforts and informs policy decisions globally. While the Red List highlights the alarming rate of biodiversity loss, it also demonstrates the potential for successful conservation interventions, as evidenced by the downlisting of species like the Giant Panda. Continued monitoring, research, and collaborative conservation efforts are crucial to mitigate the ongoing biodiversity crisis and safeguard the planet’s natural heritage.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Biodiversity Hotspot
A biodiversity hotspot is a biogeographic region with significant levels of biodiversity that is threatened with destruction.
Area of Occupancy (AOO)
The area of occupancy is the area within its geographical range that a species actually occupies, based on the presence of suitable habitat.

Key Statistics

As of 2023, the IUCN Red List assesses over 157,199 species, of which over 43,100 are threatened with extinction.

Source: IUCN Red List website (as of November 2023)

Approximately 28% of all assessed species on the IUCN Red List are considered threatened with extinction.

Source: IUCN Red List Summary Statistics (as of November 2023)

Examples

California Condor

The California Condor was brought back from the brink of extinction through a captive breeding program. In the 1980s, the population dwindled to just 22 individuals. Intensive conservation efforts, including captive breeding and reintroduction programs, have increased the population to over 500 individuals, though it remains Critically Endangered.

Frequently Asked Questions

What is the difference between ‘Endangered’ and ‘Vulnerable’?

Both are threatened categories, but ‘Endangered’ signifies a higher risk of extinction than ‘Vulnerable’. Endangered species face a very high risk, while Vulnerable species face a high risk. The quantitative criteria (population decline, range size, population size) are more stringent for Endangered.

Topics Covered

EnvironmentConservationBiodiversityExtinctionConservation Status