Functional extinction

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End of viability for a population

title: "Functional extinction" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["extinction"] description: "End of viability for a population" topic_path: "general/extinction" source: "https://en.wikipedia.org/wiki/Functional_extinction" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary End of viability for a population ::

Functional extinction is the extinction of a species or other taxon such that:

  1. It disappears from the fossil record, or historic reports of its existence cease;
  2. The reduced population no longer plays a significant role in ecosystem function;
  3. The population is no longer viable. There are no individuals able to reproduce, or the small population of breeding individuals will not be able to sustain itself due to inbreeding depression and genetic drift, which leads to a loss of fitness.

In plant populations, self-incompatibility mechanisms may cause related plant specimens to be incompatible, which may lead to functional extinction if an entire population becomes self-incompatible. This does not occur in larger populations.

In polygynous populations, where only a few males leave offspring, there is a much smaller reproducing population than if all viable males were considered. Furthermore, the successful males act as a genetic bottleneck, leading to more rapid genetic drift or inbreeding problems in small populations.

Functionally extinct species in modern times

On May 10, 2019, the Australian Koala Foundation issued a press release that opened with the sentence "The Australian Koala Foundation (AKF) believes Koalas may be functionally extinct in the entire landscape of Australia." The press release was reported on by multiple news agencies around the world, with most repeating the AKF's statement. Despite this, koalas are not currently considered functionally extinct; while their population has decreased, the IUCN Red List lists them only as "Vulnerable". The AKF's press release was released on the eve of the 2019 elections in Australia, where topics such as climate change were major issues.

Distinct animal populations can also become functionally extinct. In 2011, a 3-year survey of the wildlife population in the Bénoué Ecosystem of North Cameroon (the Bénoué, Bouba-Ndjidda, and Faro national parks, and 28 hunting zones surrounding the parks), concluded that the North Cameroon population of cheetahs (Acinonyx jubatus) and African wild dogs (Lycaon pictus) were now functionally extinct. Non-Northern Cameroonian cheetahs are listed as "Vulnerable" by the IUCN Red List.

References

References

  1. ''[https://books.google.com/books?id=UZLuF1YXYTcC Extinctions in Near Time: Causes, Contexts, and Consequences]'' 1999. Edited by R.D.E. MacPhee, [[Hans-Dieter Sues]]. page 202.
  2. "What is the link between biodiversity and ecosystem services?". Scientific Facts on Biodiversity.
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  4. Yoshida, Kate Shaw. (2013-07-12). "Not yet gone, but effectively extinct".
  5. (2018-11-13). "De-Extinction". Genes.
  6. (2014-12-26). "Males and Females Contribute Unequally to Offspring Genetic Diversity in the Polygynandrous Mating System of Wild Boar". PLOS ONE.
  7. (2009-04-01). "Polygyny can increase rather than decrease genetic diversity contributed by males relative to females: evidence from red deer". Molecular Ecology.
  8. . (2013-12-17). ["Dec 12, 2006 CE: Chinese River Dolphin Declared Extinct"](https://www.nationalgeographic.org/thisday/dec12/chinese-river-dolphin-declared-extinct/). *Mary Crooks, [[National Geographic Society]]*.
  9. . ["Yangtze Finless Porpoise"](https://www.worldwildlife.org/species/yangtze-finless-porpoise).
  10. Phillips, Tom. (2016-10-10). "China's 'extinct' dolphin may have returned to Yangtze river, say conservationists". [[The Guardian]].
  11. Xiang, Luan. (2018-05-08). "Feature: Hope prevails for the baiji dolphin's comeback". XiahuaNet.
  12. Smith, B.D.. (2017). "''Lipotes vexillifer''".
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  14. . (April 2018). ["Northern white rhinoceros on the brink of extinction"](https://www.accessscience.com/content/northern-white-rhinoceros-on-the-brink-of-extinction/BR0328011). *[[McGraw Hill]]*.
  15. Emslie, R.. (2020). "''Ceratotherium simum'' ssp. ''cottoni''".
  16. (1995). "No more hope for the Ivory-billed Woodpecker Campephilus principalis". Cotinga.
  17. BirdLife International. (2020). "''Campephilus principalis''".
  18. (2006). "Going or gone: defining 'Possibly Extinct' species to give a truer picture of recent extinctions". [[Bulletin of the British Ornithologists' Club]].
  19. . (2019-05-03). ["Ivory-billed Woodpecker Campephilus principalis"](https://www.fws.gov/verobeach/MSRPPDFs/IvoryBilledWoodpecker.pdf). *Multi-Species Recovery Plan for South Florida*.
  20. "Imperial Woodpecker (Campephilus imperialis) - BirdLife species factsheet".
  21. Platt, John R.. (2016-01-26). "The Yangtze Giant Softshell Turtle Just Got 25 Percent Closer to Extinction". Scientific American.
  22. Gibbens, Sarah. (2017-05-23). "There Are Only 3 of These Turtles Left on Earth". [[National Geographic]].
  23. Wang, Serenitie. (2019-04-15). "One of world's most endangered turtles dies, leaving 3 left". [[CNN]].
  24. Smith, Nicola. (2019-04-15). "Turtle species on brink of extinction as last-known female dies in China". [[The Daily Telegraph]].
  25. Fong, J.. (2021). "''Rafetus swinhoei''".
  26. . ["South China Tiger"](https://www.worldwildlife.org/species/south-china-tiger).
  27. Chellel, Kit. (2016-02-23). "The South China Tiger Is Functionally Extinct. This Banker Has 19 Of Them". [[Bloomberg Businessweek]].
  28. AFP. (2016-04-06). "Tigers declared extinct in Cambodia". [[The Guardian]].
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  31. link
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  34. (August 2012). "North Atlantic right whale (''Eubalaena glacialis'') 5-year review: Summary and Evaluation".
  35. Tabart, Deborah. (2019-05-10). "Australian Koala Foundation calls on the new Prime Minister to protect the Koala". The Australian Koala Foundation.
  36. Le Page, Michael. (2019-05-19). "No, koalas are not 'functionally extinct', but they are in trouble". [[New Scientist]].
  37. Woinarski, J.. (2020). "''Phascolarctos cinereus''".
  38. (Autumn 2011). "The status of cheetah and African wild dog in the Bénoué Ecosystem, North Cameroon". CATnews.
  39. Biliuti, Smaranda. (2010-07-26). "North Cameroon without African Wild Dogs or Cheetahs". [[Softpedia News]].
  40. Durant, S.M.. (2023). "''Acinonyx jubatus''".

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