What really is an endangered species?
Understanding what it means for a species to be threatened.
As society has slowly become aware of the rapid deterioration that our world is facing, efforts to halt this have begun to be made. Today, communities around the world have united under projects such as the Sustainable Development Goals adopted by the United Nations Member States in 2015, in an attempt to “end poverty, protect the planet and improve the lives and prospects of everyone, everywhere” (UN).
Among the wide array of topics under the umbrella of sustainability, one that has resonated with the global community is that of the endangerment of species. However, it remains a vague topic in the minds of many, which this article seeks to clarify.
The International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) was established in 1948 as the first global environmental union. Since then, its work has lead it to be recognized as the main international authority on the status of the natural world and the measures needed to protect it. Its reputation has even earned it a spot as a recognized observer at the United Nations General Assembly.
Today the IUCN is conformed of approximately 1,300 members spread over more than 160 countries, including some 200 governmental institutions and 1,100 NGO’s. In addition, it works directly with over 15,000 experts, which are divided among six commissions that provide the IUCN with reliable know-how and policy advice to pursue its goals.
After an initial decade focusing on the analysis of the human impact on the natural world, in 1964 the IUCN Red List of Endangered Species was established, which today is recognized as the world’s most comprehensive source of data regarding the risk of extinction of species, globally.
The Red List of Threatened Species
The work of the Red List of Threatened Species focuses on informing and boosting action for the conservation of biodiversity and policy change. Although today the general public focuses on the conservation of animal species, the Red List of Threatened Species includes within its scope animal, plant and fungus species.
To this day the Red List of Threatened Species, in partnership with the Global Species Programme, has assessed approximately 112, 400 species, of which some 31,000 are considered to be threatened, with a goal of reaching 160,000 assessed species by the end of 2020.
Categories of Endangerment
The Red List of Threatened Species classifies all species of animals, plants and fungi within nine categories according to the level of threat they face:
1. Not evaluated (NE)
2. Data deficient (DD)
3. Least Concern (LC)
4. Near threatened (NT)
5. Vulnerable (VU)
6. Endangered (EN)
7. Critically Endangered (CR)
8. Extinct in the Wild (EW)
9. Extinct (EX)
Of these nine categories, we will focus on the five to seven by first understanding the criteria used to classify species among these and then looking at the specifics for each category.
Criteria of classification for threatened species
With the aim of classifying each species according to their risk of extinction, the five indicators that have been defined are:
A. Population rate reduction — an observed, inferred, estimated, projected or suspected percentage reduction in population size over a range of 10 years or three generations, whichever is the longest.
B. Geographic range — the extent of occurrence or area of occupancy of the species in question.
C. Population size — number of known mature individuals in existence.
D. Population restrictions — number of known mature individuals in existence in combination with a particular population restriction, such as the number of specimens per subpopulation.
E. Extinction probability in the wild — a quantitative analysis showing the probability of extinction within 10 years or three generations.
Classification of threatened species
The three categories within the classification of threatened species are Vulnerable, Endangered and Critically Endangered. To be categorized under any of these they need only comply with the specifications of one of the criteria previously described.
A species is said to be vulnerable when any of the following is true:
A. Its population presents a population rate reduction of 30–50%
B. Its extent of occurrence is of less than 20,000 km2 or its area of occupancy is of less than 2,000 km2
C. The population size is of less than 10,000 mature individuals with an observed or suspected continued decline
D. Population size of less than 1,000 mature individuals or an occupancy of less than 20km2
E. It has a probability of extinction within the next hundred years of at least 10%.
A species is said to be endangered when any of the following is true:
A. Its population presents a population rate reduction of 50–70%
B. Its extent of occurrence is of less than 5,000 km2 or its area of occupancy is of less than 500 km2
C. The population size is of less than 2,500 mature individuals with an observed or suspected continued decline
D. Population size of less than 250 mature individuals or an occupancy of less than 20km2
E. It has a probability of extinction within the next twenty years or five generations, of at least 20%.
A species is said to be critically endangered when any of the following is true:
A. Its population presents a population rate reduction of 80–90%
B. Its extent of occurrence is of less than 100 km2 or its area of occupancy is of less than 10 km2
C. The population size is of less than 250 mature individuals with an observed or suspected continued decline
D. Population size of less than 10 mature individuals or an occupancy of less than 20km2
E. It has a probability of extinction within the next ten years or three generations, of at least 50%.
References:
· IUCN 2020. The IUCN Red List of Threatened Species. Version 2020–1. https://www.iucnredlist.org. Downloaded on 19 March 2020.
· IUCN. (2012). IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, UK: IUCN. iv + 32pp
