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Rare species

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(Redirected from Species rarity)
For the album by Waltari, see Rare Species (album).

A rare species is a group of organisms that are very uncommon, scarce, or infrequently encountered. This designation may be applied to either a plant or animal taxon, and is distinct from the term endangered or threatened. Designation of a rare species may be made by an official body, such as a national government, state, or province. The term more commonly appears without reference to specific criteria. The International Union for Conservation of Nature does not normally make such designations, but may use the term in scientific discussion.[1]

Rarity rests on a specific species being represented by a small number of organisms worldwide, usually fewer than 10,000. However, a species having a very narrow endemic range or fragmented habitat also influences the concept.[2][3] Almost 75% of known species can be classified as "rare".[4]

Rare species are species with small populations. Many will move into the endangered or vulnerable category if the negative factors affecting them continue to operate. Well-known examples of rare species - because these are large terrestrial animals - include the Himalayan brown bear, Fennec fox, Wild Asiatic buffalo, or the Hornbill.

They are not endangered yet, but classified as "at risk",[5][6] although the frontier between these categories is increasingly difficult to draw given the general paucity of data on rare species. This is especially the case in the world Ocean where many 'rare' species not seen for decades may well have gone extinct unnoticed, if they are not already on the verge of extinction like the Mexican Vaquita.[7]

A species may be endangered or vulnerable, but not considered rare if it has a large, dispersed population. IUCN uses the term "rare" as a designation for species found in isolated geographical locations. Rare species are generally considered threatened because a small population size is less likely to recover from ecological disasters.

Rare plants can be classified based on the size and distribution of their populations. Some species may be rare because they consist of only a few individuals, are confined to a limited geographic area, or both. Certain rare plants are found sparsely distributed across a wide area. Others might have a large number of individuals that are concentrated in a very small area, such as a single county or canyon. The rarest plants typically have both a small number of individuals and a very limited geographic range.

Assessments of the status of rare plants are conducted using the best available data and consider various factors, including:

  • Total number of occurrences and the condition of these populations
  • Population size
  • Extent of range and area occupied
  • Trends in population size and distribution over the short and long term
  • Nature, severity, and urgency of threats
  • Number of occurrences that are protected and actively managed
  • Intrinsic vulnerability of the species
  • Specificity to environmental conditions[8]

A rare plant's legal status can be observed through the USDA's Plants Database.

Critically Endangered, Possibly Extinct

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Common name Scientific name Image Last sighting Estimated population of mature individuals Endemic geographic location
La Vega Racer Hypsirhynchus melanichnus 1910 0-25 Hispaniola
Hispaniolan two-lined skink Mabuya hispaniolae 1937 0-50 Dominican Republic
Hispaniolan Ten-lined Skink Spondylurus lineolatus 1985 0-50 Hispaniola (northern Haiti and northwestern Dominican Republic)
Gloomy tube-nosed bat Murina tenebrosa 1962 0-1 Tsushima Island & Yakushima, Japan
Emperor rat Uromys imperator 1959 or prior 0-3
Guadalcanal rat Uromys porculus 1888 0-3
One-striped opossum Monodelphis unistriata 9 April 1899 0-10
Baiji Lipotes vexillifer 14 May 2024 0-19
Glacous macaw Anodorhynchus glaucus 1951 0-20
Angel Island mouse Peromyscus guardia 1991 0-49
Aru flying fox Pteropus aruensis 1867 0-49 Trangan, Indonesia
Cuban ivory-billed woodpecker Campephilus principalis bairdii 28 April 1987 0-49 Cuba
Imperial woodpecker Campephilus imperialis 1956 0-49
Emma's giant rat Uromys emmae 1994 0-49 Owi Island, Indonesia
Ethiopian amphibious rat Nilopegamys plumbeus 1928 0-49
Garrido's hutia Capromys garridoi 1989 0-49 Banco de los Jardins y Jardinillos, Canarreos Archipelago, Cuba
Zuniga's melanomys Melanomys zunigae 1949 0-49 Lima Department, Peru
Dwarf hutia Mesocapromys nana 26 October 1951 0-50 Zapata Swamp, Cuba
New Zealand greater short-tailed bat Mystacina robusta 23 January 1967 0-50
Puebla deer mouse Peromyscus mekisturus 1948 0-50
Kouprey Bos sauveli 1988 0-50
Montane monkey-faced bat Pteralopex pulchra 17 May 1990 0-50
San Felipe hutia Mesocapromys sanfelipensis 1978 0-99 Cayo de Juan Garcia & Cayos de San Felipe, Cuba
Christmas Island shrew Crocidura trichura 1998 0-200
Malabar large-spotted civet Viverra civettina 1993 0-249

Critically Endangered / Extinct in the Wild

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Common name Scientific name Image Last sighting International Union for Conservation of Nature Red List of Threatened Species category and criteria Present estimated wildlife population Present estimated captive population Present estimated total population Endemic geographic location
Northern white rhinoceros Ceratotherium simum cottoni N/A Critically Endangered (Possibly Extinct in the Wild) A2abcd; C1+2a(i,ii); D 0 2 2
Barbary lion Panthera leo leo N/A Extinct in the Wild 0 98 98 Belfast Zoo, Ireland

Rabat Zoo, Morocco Keystone Safari, United States

Yangtze giant softshell turtle Rafetus swinhoei N/A Critically Endangered A2acd; D 2 1 3
American ivory-billed woodpecker Campephilus principalis principalis 8 April 2022 Critically Endangered D 1-50 0 1-50
Fernandina Island Galápagos tortoise Chelonoidis niger phantasticus N/A Critically Endangered (Possibly Extinct) D 0-5 1 1-6
Northern Sumatran rhinoceros Dicerorhinus sumatrensis lasiotis 1993 Critically Endangered A2abd; C1+2a(i) 0-9 0 0-9 Tamanthi Wildlife Sanctuary, Myanmar
Vaquita Phocoena sinus May 2024 Critically Endangered A2a; C1+2a(ii); D; E 6-10 0 6-10
Baishanzu fir Abies beshanzuensis N/A Critically Endangered D 3 1-9 4-12
Bornean rhinoceros Dicerorhinus sumatrensis harrissoni N/A Critically Endangered A2cd+3cd+4cd; C2a(i); D 0-14 1 1-15
Wood's cycad Encephalartos woodii N/A Extinct in the Wild 0 1-36 1-36 Kirstenbosch National Botanical Garden, South Africa
Loneliest palm Hyophorbe amaricaulis N/A Critically Endangered ??? 1 1 Curepipe Botanic Gardens, Mauritius
Hainan black crested gibbon Nomascus hainanus 2023 Critically Endangered A2acd; B1ab(iii); D 36-37 0 36-37
Gobi bear Ursus arctos gobiensis 12 April 2023 Critically Endangered 30-40 0 30-40
Māui dolphin Cephalorhynchus hectori maui 28 January 2023 Critically Endangered A2cd+4cd; C2a(i,ii); D 48-64 0 48-64
Colossal squid Mesonychoteuthis hamiltoni 2015 Least Concern ??? 0 ???
Indonesian Javan rhinoceros Rhinoceros sondaicus sondaicus 17 March 2023 Critically Endangered D 76-80 0 76-80
Western Sumatran rhinoceros Dicerorhinus sumatrensis sumatrensis N/A Critically Endangered A2cd+3cd+4cd; C2a(i); D 30-80 7-8 37-88
Ornate Ground snake Erythrolamprus ornatus 2012 Critically Endangered D 18-100 0 18-100 Maria Islands Nature Reserve, Saint Lucia
Saola Pseudoryx nghetinhensis August 2013 Critically Endangered A2acd+3cd+4acd; C2a(i) 20-100 0 20-100
Alagoas curassow Mitu mitu N/A Extinct in the Wild 0 50-100 50-100
Horrid ground-weaver Nothophantes horridus N/A Critically Endangered A3c 1-99 1-9 2-108
Cat Ba langur Trachypithecus poliocephalus 8 November 2022 Critically Endangered D 130-150 0 130-150
Siau scops owl Otus siaoensis 2017 Critically Endangered D 50-200 0 50-200 Siau Island, Indonesia
South China tiger Panthera tigris amoyensis N/A Critically Endangered (Possibly Extinct in the Wild) 0 150-200 150-200
Devils Hole pupfish Cyprinodon diabolis N/A Critically Endangered B1ab(v)+2ab(v); C2a(ii) 100-200 1-9 101-209 Devils Hole, Death Valley National Park, United States of America
Loa water frog Telmatobius dankoi N/A Critically Endangered B1ab(iii)+2ab(iii) 1-9 214 215-223 Small streams along the Loa River southwest of Calama, Chile
Bleeding toad Leptophryne cruentata 2003 Critically Endangered C2a(i) 1-249 0 1-249
Black-naped pheasent pigeon Otidiphaps insularis September 2022 Critically Endangered 50-249 0 50-249 Fergusson Island, Papua New Guinea
Ganges shark Glyphis gangeticus February 2016 Critically Endangered A2cd; C2a(i) 1-249 0 1-249
Pink-headed duck Rhodonessa caryophyllacea June 1935 Critically Endangered 1-49 0 ???
New Guinea big-eared bat Pharotis imogene March 2014 Critically Endangered D 49-249 0 49-249
Wimmer's shrew Crocidura wimmeri 1988 Critically Endangered B1ab(iii) 5-250 0 5-250
Archer's lark Heteromirafra archeri 2003 Critically Endangered A3bc; C2a(i) 50-250 0 50-250
Spix's Macaw Cyanopsitta spixii N/A Extinct in the Wild 0 200-300 200-300
Kākāpō Strigops habroptilus N/A Critically Endangered A2be 0 250-300 250-300
Gurney's pitta Hydrornis gurneyi 2016 Critically Endangered A3c 50-300 0-5 55-305
Cross River gorilla Gorilla gorilla diehli N/A Critically Endangered C2a(i) 250-300 1-9 251-309
Philippine eagle Pithecophaga jefferyi N/A Critically Endangered A2cd; C2a(ii) 250-300 10-20 260-320
Amur leopard Panthera pardus orientalis N/A Critically Endangered C2a(ii); D 60-125 217 277-342
North Atlantic right whale Eubalaena glacialis 22 August 2023 Critically Endangered C2a(ii) 350-400 0 350-400
Black softshell turtle Nilssonia nigricans N/A Critically Endangered A4cd 1-499 50-100 51-599
California condor Gymnogyps californianus N/A Critically Endangered C2a(i); D 300-350 150-200 450-550
Cumberlandian combshell Epioblasma brevidens N/A Critically Endangered A1ce 200–1,000 ? 200-1,000
De Winton's golden mole Cryptochloris wintoni N/A Critically Endangered (Possibly Extinct) B1ab(iii)+2ab(iii) 1-999 1-9 2-1,008
Lord Howe Island stick insect Dryococelus australis N/A Critically Endangered D 1-49 500–1,000 501-1,049 Ball's Pyramid, Australia
Wild Bactrian camel Camelus ferus N/A Critically Endangered A3de+4ade 1,000-1,500 100-200 1,100-1,700
Key tree-cactus Pilosocereus robinii N/A Extinct in the Wild 0 200–2,000 200-2,000
Central rock rat Zyzomys pedunculatus N/A Critically Endangered A2abce 500–2,000 1-9 501-2,009
Eastern lowland gorilla Gorilla beringei graueri N/A Critically Endangered A4bcd 3,800-5,000 1-19 3,801-5,019

See also

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References

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  1. ^ "Assessment Process". www.iucnredlist.org. Retrieved 2017-11-14.
  2. ^ R. MacNally and G. W. Brown, Reptiles and Habitat Fragmentation in the Box-ironbush Forests of Central Victoria, Australia: Predicting Compositional Change and Faunal Nested-ness, Oecologia 128:116–125 (2001).
  3. ^ Prendergast, J. R.; Quinn, R. M.; Lawton, J. H.; Eversham, B. C.; Gibbons, D. W. (1993-09-23). "Rare species, the coincidence of diversity hotspots and conservation strategies". Nature. 365 (6444): 335–337. Bibcode:1993Natur.365..335P. doi:10.1038/365335a0.
  4. ^ Dinerstein, Eric (2013) The Kingdom of Rarities. Island Press. ISBN 9781610911955.
  5. ^ "Rare Species". www.encyclopedia.com. Retrieved 2017-11-15.
  6. ^ "IUCN – A brief history". IUCN. 2017-10-06. Archived from the original on 2017-11-15. Retrieved 2017-11-15.
  7. ^ Briand, Frederic (October 2012). "Species Missing in Action - Rare or Already Extinct?". National Geographic.
  8. ^ "What is a rare plant?". www.fs.usda.gov. Retrieved 2024-04-12.
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Further reading

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