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Extinct in the wild

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The Hawaiian crow has been listed as extinct in the wild since 2004.
The Guam kingfisher has been extinct in the wild since 1986.
Conservation status
Extinct
Threatened
Lower Risk
Other categories
Related topics
IUCN Red List category abbreviations (version 3.1, 2001)
Comparison of Red List classes above
and NatureServe status below
NatureServe category abbreviations

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.[1][2] Classification requires exhaustive surveys conducted within the species' known habitat with consideration given to seasonality, time of day, and life cycle.[2][3] Once a species is classified as EW, the only way for it to be downgraded[3] is through reintroduction.[3][4]

Not all EW species are rare. An example is the Brugmansia family, where all seven species are widely cultivated, but none are found in the wild.[5] Ultimately, the purpose of preserving biodiversity is to maintain ecological function to prevent ecological extinction.

Examples

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Examples of species and subspecies that are extinct in the wild include (in alphabetical order):

Conservation

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Main article: Wildlife conservation

Reintroduction

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Main article: Reintroduction

Reintroduction is the deliberate release of individuals into the wild, from captivity or from other areas where the species survives. However, it may be difficult to reintroduce EW species into the wild, even if their natural habitats were restored, because survival techniques, which are often passed from parents to offspring during parenting, may have been lost. Reintroduction efforts, also referred to as translocation, are complex and a common source of complication is how animals behave upon release.[33] Climate suitability has been shown to influence reintroduction outcomes as well.[34] Though many efforts translocate populations to historic ranges, climate change may be causing those previously inhabited areas to no longer be suitable for the species.[34]

Przewalski's horse has been reintroduced, its status going from extinct in the wild to endangered.

The Przewalski's horse was downgraded from EW to Endangered in 2011 after decades of reintroduction efforts.[35] In China, they are still classified as EW since they are given supplemental feed over the winter to aid survival.[35] Of the 2500 living, about 1360 are in the wild, and all 2500 are descended from 12 wild-caught ancestors, causing an inbreeding depression that contributes to factors, such as shorter lifespans and high mortality, that impede conservation.[35]

A northern white rhino, an EW species, at the San Diego Zoo Safari Park

Northern white rhinos have been extinct in the wild since 2007, and only two females remain in captivity.[36] The San Diego Zoo Global is planning to save the species by using living cells from 12 rhinos that have been cryopreserved, turning them into stem cell lines, using in vitro fertilization to create embryos, and then having Southern white rhinos serve as surrogates.[36] Currently, there have been no successful embryo transfers in rhinos.[36] It is estimated to take at least 40 years for the target of 25–40 northern white rhinos to be reached.[36]

Some people critique efforts to save species with such small populations due to the possibility of inbreeding as it can reduce the population growth rate.[37] Small effective population sizes are another critique. Effective population size is a measurement of the loss of genetic diversity.[38] Multiple populations have been found to have an effective population size below conservation goals.[38] Additionally, monitoring effective population size and using it to aid estimations of the success of conservation efforts has been shown to provide a better overview of determining population trends when compared to population size.[39]

IUCN Green Status of Species

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Main article: IUCN Green Status of Species

The IUCN developed a system of classifying species recovery efforts in 2012 entitled the Green Status.[40] The species recovery score is a 0%–100% scale, with 0% being the species is extinct or extinct in the wild and 100% being fully recovered.[40] In addition, the Green Status also classifies previous and future conservation impacts with the Green Scores of Conservation Dependency, Conservation Gain, Conservation Legacy, and Recovery Potential.[40][41]

For a species to receive a score of 100% and be considered fully recovered, three requirements must be met: the species must be present in all areas of both its current and historical range, it is viable in all areas of the range, and performs its ecological niche across the full range.[41] Given the lofty standards, many species are not expected to meet the criteria and it is not a goal of this system. Land use changes have cumulated in many species losing habitat.[41]

Green Scores are snapshots in time to assess a species' current status and how conservation efforts have influenced their status.[41] It is also predictive as it can project how the status would change if conservation efforts ceased or continued.[41] Conservation Legacy assess how previous conservation work has changed or maintained a species' status. The score ranges from high to low with low meaning conservation efforts were ineffective or did not occur.[41] Conservation Dependency is the estimate of a species' status in 10 years if conservation efforts halted. High dependency means the species would have a lower status and low dependency equates to the status not changing.[41] Conservation Gain is the flip side. It projects a species' status in 10 years if conservation efforts continue.[41] Both dependence and gain are considered short-term measures. The long-term measure is Recovery Potential, which is how much of the range is estimated to be able to house ecologically functional populations.[41] 

Flagship species

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Main article: Flagship species
Lonesome George

The Pinta Island tortoise (Geochelone nigra abingdoni) had only one living individual, named Lonesome George, until his death in June 2012.[42] The tortoise was believed to be extinct in the mid-20th century, until Hungarian malacologist József Vágvölgyi spotted Lonesome George on the Galapagos island of Pinta on 1 December 1971. Since then, Lonesome George has been a powerful symbol for conservation efforts in general and for the Galapagos Islands in particular.[43] With his death on 24 June 2012, the subspecies is again believed to be extinct.[44] With the discovery of 17 hybrid Pinta tortoises located at nearby Wolf Volcano, a plan has been made to attempt to breed the subspecies back into a pure state.[45]

See also

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References

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  1. ^ "2001 IUCN Red List Categories and Criteria: Version 3.1" (PDF). IUCN. p. 14. Archived from the original (PDF) on 21 June 2010. Retrieved 30 May 2010.
  2. ^ a b "The IUCN Red List Categories and Criteria". IUCN Red List.
  3. ^ a b c IUCN. (2003). Guidelines for Application of IUCN Red List Criteria at Regional Levels: Version 3.0. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, UK. ii + 26 pp.
  4. ^ "Reasons for Changing Category". IUCN Red List.
  5. ^ Petruzzello, Melissa. "Extinct in the Wild but Still Around: 5 Plants and Animals Kept Alive by Humans". Encyclopædia Britannica. Retrieved 16 November 2019.
  6. ^ Bárrios, S.; Smyth, N. (2018). "Abutilon pitcairnense". IUCN Red List of Threatened Species. 2018: e.T122926206A122926208. Retrieved 16 December 2023.
  7. ^ "Alagoas Curassow (Mitu mitu)". IUCN Red List of Threatened Species. 7 August 2018. 7 August 2018. Archived from the original on 15 December 2023.
  8. ^ Freyhof, J.; Kottelat, M. (2008). "Stenodus leucichthys (Caspian Inconnu)". IUCN Red List of Threatened Species. 2008: e.T20745A9229071. doi:10.2305/IUCN.UK.2008.RLTS.T20745A9229071.en. Archived from the original on 15 December 2023.
  9. ^ Johnson, D. (1998). "Corypha taliera". IUCN Red List of Threatened Species. 1998: e.T38493A10118302. Retrieved 16 December 2023.
  10. ^ "Christmas Island Blue-tailed Shinning-skink (Cryptoblepharus egeriae)". IUCN Red List of Threatened Species. 20 February 2017. 20 February 2017. Archived from the original on 15 December 2023.
  11. ^ Qiwei, W. (2022). "Acipenser dabryanus (Yangtze Sturgeon)". IUCN Red List of Threatened Species. 2022: e.T231A61462199. Archived from the original on 15 December 2023. Retrieved 3 September 2022.
  12. ^ Donaldson, J.S. (2010). "Encephalartos brevifoliolatus (Escarpment Cycad)". IUCN Red List of Threatened Species. 2010: e.T41882A10566751. doi:10.2305/IUCN.UK.2010-3.RLTS.T41882A10566751.en.
  13. ^ "Franklin Tree (Franklinia alatamaha)". IUCN Red List of Threatened Species. 3 February 2015. 3 February 2015. Archived from the original on 15 December 2023.
  14. ^ "Golden Skiffia (Skiffia francesae)". IUCN Red List of Threatened Species. 18 April 2018. 18 April 2018. Archived from the original on 15 December 2023.
  15. ^ "Guam Kingfisher (Todiramphus cinnamominus)". IUCN Red List of Threatened Species. October 2016. October 2016. Archived from the original on 15 December 2023.
  16. ^ "Hawaiian Crow (Corvus hawaiiensis)". IUCN Red List of Threatened Species. October 2016. October 2016. Archived from the original on 12 June 2023.
  17. ^ Keysor Espenschied, Susan (27 September 2017). "'Alalā released into natural area reserve". Aliso Laguna News. Archived from the original on 27 April 2023.
  18. ^ Ako, Diane (16 October 2017). "Rare Hawaiian crows released into native forests of Hawai'i Island". KITV4. Archived from the original on 24 October 2021. Retrieved 10 February 2020.
  19. ^ Brestovansky, Michael (1 October 2018). "Five more alala released into Puu Makaala Forest Reserve". West Hawaii Today. Archived from the original on 10 May 2023.
  20. ^ "Nectophrynoides asperginis". IUCN Red List of Threatened Species. 25 July 2014. 25 July 2014.
  21. ^ "La Palma Pupfish (Cyprinodon longidorsalis)". IUCN Red List of Threatened Species. 27 September 2018. 27 September 2018. Archived from the original on 15 December 2023.
  22. ^ "Christmas Island Chained Gecko (Lepidodactylus listeri)". IUCN Red List of Threatened Species. 20 February 2017. 20 February 2017.
  23. ^ "Leptogryllus deceptor". IUCN Red List of Threatened Species. August 1996. August 1996.
  24. ^ "'Last wave' for wild golden frog". BBC. 2 February 2008. Retrieved 22 February 2015.
  25. ^ "Père David's Deer (Elaphurus davidianus)". IUCN Red List of Threatened Species. 31 March 2016. 31 March 2016.
  26. ^ Yang, R., Zhang, L., Tan, B. and Zhong, Z. 2003. Investigation on the status of Père David's deer in China. Chinese Journal of Zoology 38: 76~81.
  27. ^ "Zenaida graysoni (Socorro Dove)". IUCN Red List of Threatened Species. October 2016. October 2016.
  28. ^ "Thermosphaeroma thermophilum". IUCN Red List of Threatened Species. August 1996. August 1996.
  29. ^ "South China Tiger". World Wide Fund for Nature.
  30. ^ "Panthera tigris amoyensis". IUCN Red List of Threatened Species. 30 June 2008. 30 June 2008.
  31. ^ "Spix's Macaw". IUCN Red List of Threatened Species. 20 June 2019. 20 June 2019.
  32. ^ "Wyoming Toads Begin To Recover As States Seek Endangered Species Act Overhaul". NPR.
  33. ^ Berger-Tal, O.; Blumstein, D. T.; Swaisgood, R. R. (April 2020). "Conservation translocations: a review of common difficulties and promising directions". Animal Conservation. 23 (2): 121–131. Bibcode:2020AnCon..23..121B. doi:10.1111/acv.12534. ISSN 1367-9430.
  34. ^ a b Bellis, Joe; Bourke, David; Maschinski, Joyce; Heineman, Katie; Dalrymple, Sarah (December 2020). "Climate suitability as a predictor of conservation translocation failure". Conservation Biology. 34 (6): 1473–1481. Bibcode:2020ConBi..34.1473B. doi:10.1111/cobi.13518. ISSN 0888-8892. PMID 32304113.
  35. ^ a b c Turghan, Mardan Aghabey; Jiang, Zhigang; Niu, Zhongze (15 November 2022). "An Update on Status and Conservation of the Przewalski's Horse (Equus ferus przewalskii): Captive Breeding and Reintroduction Projects". Animals. 12 (22): 3158. doi:10.3390/ani12223158. ISSN 2076-2615. PMC 9686875. PMID 36428386.
  36. ^ a b c d Ryder, Oliver A.; Friese, Carrie; Greely, Henry T.; Sandler, Ronald; Saragusty, Joseph; Durrant, Barbara S.; Redford, Kent H. (August 2020). "Exploring the limits of saving a subspecies: The ethics and social dynamics of restoring northern white rhinos (Ceratotherium simum cottoni)". Conservation Science and Practice. 2 (8). Bibcode:2020ConSP...2E.241R. doi:10.1111/csp2.241. ISSN 2578-4854.
  37. ^ Bozzuto, Claudio; Biebach, Iris; Muff, Stefanie; Ives, Anthony R.; Keller, Lukas F. (2 September 2019). "Inbreeding reduces long-term growth of Alpine ibex populations". Nature Ecology & Evolution. 3 (9): 1359–1364. Bibcode:2019NatEE...3.1359B. doi:10.1038/s41559-019-0968-1. hdl:11250/2637691. ISSN 2397-334X. PMID 31477848.
  38. ^ a b Husemann, M; Zachos, F E; Paxton, R J; Habel, J C (October 2016). "Effective population size in ecology and evolution". Heredity. 117 (4): 191–192. doi:10.1038/hdy.2016.75. ISSN 0018-067X. PMC 5026761. PMID 27553454.
  39. ^ Wang, J; Santiago, E; Caballero, A (October 2016). "Prediction and estimation of effective population size". Heredity. 117 (4): 193–206. doi:10.1038/hdy.2016.43. ISSN 0018-067X. PMC 5026755. PMID 27353047.
  40. ^ a b c Grace, Molly K.; Akçakaya, H. Resit; Bennett, Elizabeth L.; Brooks, Thomas M.; Heath, Anna; Hedges, Simon; Hilton-Taylor, Craig; Hoffmann, Michael; Hochkirch, Axel; Jenkins, Richard; Keith, David A.; Long, Barney; Mallon, David P.; Meijaard, Erik; Milner-Gulland, E.J. (December 2021). "Testing a global standard for quantifying species recovery and assessing conservation impact". Conservation Biology. 35 (6): 1833–1849. Bibcode:2021ConBi..35.1833G. doi:10.1111/cobi.13756. hdl:10919/108163. ISSN 0888-8892. PMID 34289517.
  41. ^ a b c d e f g h i "The IUCN Green Status of Species". IUCN Red List.
  42. ^ Gardner, Simon (6 February 2001). "Lonesome George faces own Galapagos tortoise curse". Archived from the original on 4 June 2011.
  43. ^ Nicholls, H. (2006). Lonesome George: The Life and Loves of a Conservation Icon. London, England: Macmillan Science. ISBN 1-4039-4576-4. Archived from the original on 14 September 2011. Retrieved 28 April 2011.
  44. ^ "Last Pinta giant tortoise Lonesome George dies". BBC News. 24 June 2012. Retrieved 25 June 2012.
  45. ^ "Scientists: Extinct Galapagos tortoise species could be resurrected". CTV News. 22 November 2012. Retrieved 25 November 2012.
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