Critically Endangered

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Pygmy three-toed sloth, a species of sloth with a conservation status of Critically Endangered. Perezoso La Mochila.jpg
Pygmy three-toed sloth , a species of sloth with a conservation status of Critically Endangered.

An IUCN Red List Critically Endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. [1] As of December 2023, of the 157,190 species currently on the IUCN Red List, 9,760 of those are listed as Critically Endangered, with 1,302 being possibly extinct and 67 possibly extinct in the wild. [2]

Contents

The IUCN Red List provides the public with information regarding the conservation status of animal, fungi, and plant species. [3] It divides various species into seven different categories of conservation that are based on habitat range, population size, habitat, threats, etc. Each category represents a different level of global extinction risk. Species that are considered to be Critically Endangered are placed within the "Threatened" category. [4]

As the IUCN Red List does not consider a species extinct until extensive targeted surveys have been conducted, species that are possibly extinct are still listed as Critically Endangered. IUCN maintains a list [5] of "possibly extinct" and "possibly extinct in the wild" species, modelled on categories used by BirdLife International to categorize these taxa.

Criteria

To be defined as Critically Endangered in the Red List, a species must meet any of the following criteria (A–E) ("3G/10Y" signifies three generations or ten years—whichever is longer—over a maximum of 100 years; "MI" signifies Mature Individuals): [6]

A: Population Size Reduction
  1. The rate of reduction is measured either over a 10 year span or across three different generations within that species.
  2. The cause for this decline must also be known.
  3. If the reasons for population reduction no longer occur and can be reversed, the population needs to have been reduced by at least 90%
  4. If not, then the population needs to have been reduced by at least 80%
B: Reduction Across a Geographic Range
  1. This reduction must occur over less than 100 km2 OR the area of occupancy is less than 10 km2.
    1. Severe habitat fragmentation or existing at just one location
    2. Decline in extent of occurrence, area of occupancy, area/extent/quality of habitat, number of locations/subpopulations, or amount of MI.
    3. Extreme fluctuations in extent of occurrence, area of occupancy, number of locations/subpopulations, or amount of MI.
C: Population Decline
  1. The population must decline to less than 250 MI and either:
    1. A decline of 25% over 3G/10Y
    2. Extreme fluctuations, or over 90% of MI in a single subpopulation, or no more than 50 MI in any one subpopulation.
D: Population Size Reduction
  1. The population size must be reduced to numbers of less than 50 MI.
E: Probability of Extinction
  1. There must be at least a 50% probability of going extinct in the wild within over 3G/10Y

Causes

The Beluga sturgeon (Huso huso) is an example of a critically endangered species. Their wild populations have been reduced due to overharvesting for its caviar. Biluga (Huso huso).jpg
The Beluga sturgeon ( Huso huso ) is an example of a critically endangered species. Their wild populations have been reduced due to overharvesting for its caviar.

The current extinction crisis is witnessing extinction rates that are occurring at a faster rate than that of the natural extinction rate. It has largely been credited towards human impacts on climate change and the loss of biodiversity. This is along with natural forces that may create stress on the species or cause an animal population to become extinct. [7]

Currently the biggest reason for species extinction is human interaction resulting in habitat loss. [8] Species rely on their habitat for the resources needed for their survival. If the habitat becomes destroyed, the population will see a decline in their numbers. Activities that cause loss of habitat include pollution, urbanization, and agriculture. Another reason for plants and animals to become endangered is due to the introduction of invasive species. Invasive species invade and exploit a new habitat for its natural resources as a method to outcompete the native organisms, eventually taking over the habitat. This can lead to either the native species' extinction or causing them to become endangered, which also eventually causes extinction. Plants and animals may also go extinct due to disease. The introduction of a disease into a new habitat can cause it to spread amongst the native species. Due to their lack of familiarity with the disease or little resistance, the native species can die off.

Related Research Articles

This is an index of conservation topics. It is an alphabetical index of articles relating to conservation biology and conservation of the natural environment.

<span class="mw-page-title-main">IUCN Red List</span> Inventory of the global conservation status of biological species

The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological species. A series of Regional Red Lists, which assess the risk of extinction to species within a political management unit, are also produced by countries and organizations.

A threatened species is any species which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of critical depensation, a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment without direct reference to human activity.

<span class="mw-page-title-main">Lear's macaw</span> Species of bird

Lear's macaw, also known as the indigo macaw, is a large all-blue Brazilian parrot, a member of a large group of neotropical parrots known as macaws. It was first described by Charles Lucien Bonaparte in 1856. Lear's macaw is 70–75 cm long and weighs around 950 g. It is coloured almost completely blue, with a yellow patch of skin at the base of the heavy, black bill.

Local extinction, also extirpation, is the termination of a species in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions.

The conservation status of a group of organisms indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation status: not simply the number of individuals remaining, but the overall increase or decrease in the population over time, breeding success rates, and known threats. Various systems of conservation status are in use at international, multi-country, national and local levels, as well as for consumer use such as sustainable seafood advisory lists and certification. The two international systems are by the International Union for Conservation of Nature (IUCN) and The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

<span class="mw-page-title-main">Riverine rabbit</span> Species of mammal

The riverine rabbit, also known as the bushman rabbit or bushman hare, is a rabbit with an extremely limited distribution area, found only in the central and southern regions of the Karoo Desert of South Africa's Northern Cape Province. It is the only member of the genus Bunolagus because of unique traits that separate it from the other leporids. It is one of the most endangered mammals in the world, with only around 500 living adults, and 1500 overall.

A conservation-dependent species is a species which has been categorized as "Conservation Dependent" ("LR/cd") by the International Union for Conservation of Nature (IUCN), as dependent on conservation efforts to prevent it from becoming endangered. A species that is reliant on the conservation attempts of humans is considered conservation dependent. Such species must be the focus of a continuing species-specific and/or habitat-specific conservation program, the cessation of which would result in the species qualifying for one of the threatened categories within a period of five years. The determination of status is constantly monitored and can change.

An endangered species recovery plan, also known as a species recovery plan, species action plan, species conservation action, or simply recovery plan, is a document describing the current status, threats and intended methods for increasing rare and endangered species population sizes. Recovery plans act as a foundation from which to build a conservation effort to preserve animals which are under threat of extinction. More than 320 species have died out and the world is continuing a rate of 1 species becoming extinct every two years. Climate change is also linked to several issues relating to extinct species and animals' quality of life.

The IUCN has many ranks that define an animal's population and risk of extinction. Species are classified into one of nine Red List Categories: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient, and Not Evaluated. They formerly used a identification called lower risk to describe some animals.

The Threatened Species Protection Act 1995, is an act of the Parliament of Tasmania that provides the statute relating to conservation of flora and fauna. Its long title is An Act to provide for the protection and management of threatened native flora and fauna and to enable and promote the conservation of native flora and fauna. It received the royal assent on 14 November 1995.

<span class="mw-page-title-main">Extinct in the wild</span> IUCN conservation category

A species that is extinct in the wild (EW) is one that has been categorized by the International Union for Conservation of Nature as only consisting of living members kept in captivity or as a naturalized population outside its historic range. Classification requires exhaustive surveys conducted within the species' known habitat with consideration given to seasonality, time of day, and life cycle. Once a species is classified as EW, the only way for it to be downgraded is through reintroduction.

<span class="mw-page-title-main">Christmas Island shrew</span> Species of mammal

The Christmas Island shrew, also known as the Christmas Island musk-shrew is an extremely rare or possibly extinct shrew from Christmas Island. It was variously placed as subspecies of the Asian gray shrew or the Southeast Asian shrew, but morphological differences and the large distance between the species indicate that it is an entirely distinct species.

<span class="mw-page-title-main">Endangered species</span> Species of some organisms facing a very high risk of extinction

An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, invasive species, and climate change. The International Union for Conservation of Nature (IUCN) Red List lists the global conservation status of many species, and various other agencies assess the status of species within particular areas. Many nations have laws that protect conservation-reliant species which, for example, forbid hunting, restrict land development, or create protected areas. Some endangered species are the target of extensive conservation efforts such as captive breeding and habitat restoration.

<span class="mw-page-title-main">Cantabrian capercaillie</span> Subspecies of bird

The Cantabrian capercaillie is a subspecies of the western capercaillie in the grouse family Tetraonidae. It is one of two subspecies found in Spain.

<span class="mw-page-title-main">Vulnerable species</span> IUCN conservation category

A vulnerable species is a species which has been categorized by the International Union for Conservation of Nature as being threatened with extinction unless the circumstances that are threatening its survival and reproduction improve.

<span class="mw-page-title-main">Endangered species (IUCN status)</span> Species which have been categorized as very likely to become extinct in the near future

Endangered species, as classified by the International Union for Conservation of Nature (IUCN), are species which have been categorized as very likely to become extinct in their known native ranges in the near future. On the IUCN Red List, endangered is the second-most severe conservation status for wild populations in the IUCN's schema after critically endangered. In 2012, the IUCN Red List featured 3,079 animal and 2,655 plant species as endangered worldwide. The figures for 1998 were 1,102 and 1,197 respectively.

References

  1. ↑ "IUCN RED LIST CATEGORIES AND CRITERIA" (PDF). 2000-02-09. Retrieved 2018-02-06.
  2. ↑ "IUCN Red List of Threatened Species". IUCN. Retrieved January 19, 2024.
  3. ↑ "What is The IUCN Red List?". IUCN Red List. Retrieved August 13, 2020.
  4. ↑ "Endangered Species". National Geographic. March 17, 2011. Retrieved August 13, 2020.
  5. ↑ "Summary Statistics". www.iucnredlist.org. Retrieved 2017-12-10.
  6. ↑ IUCN (February 2014). "Guidelines for Using the IUCN Red List Categories and Criteria" (PDF). Archived from the original (PDF) on 2 May 2015. Retrieved 10 December 2018.
  7. ↑ Chandler, David (November 22, 2019). "What Are the Causes of Animals Becoming Endangered?". Sciencing. Retrieved August 20, 2020.
  8. ↑ "What Causes Extinction". American Museum of Natural History. Retrieved October 7, 2022.
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