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:
A rare plant's legal status can be observed through the USDA's Plants Database.
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 | 100 | 100 | Belfast Zoo, Ireland | |
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 | 0-5 | 0 | 0-5 | ||
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, Mauritus | |
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 | ||
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 |
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.
The NatureServe conservation status system, maintained and presented by NatureServe in cooperation with the Natural Heritage Network, was developed in the United States in the 1980s by The Nature Conservancy (TNC) as a means for ranking or categorizing the relative imperilment of species of plants, animals, or other organisms, as well as natural ecological communities, on the global, national or subnational levels. These designations are also referred to as NatureServe ranks, NatureServe statuses, or Natural Heritage ranks. While the Nature Conservancy is no longer substantially involved in the maintenance of these ranks, the name TNC ranks is still sometimes encountered for them.
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).
Potentilla hickmanii is an endangered perennial herb of the rose family. This rare plant species is found in a narrowly restricted range in two locations in coastal northern California, in Monterey County, and in very small colonies in San Mateo County. This small wildflower, endemic to western slopes of the outer coastal range along the Pacific Ocean coast, produces bright yellow blossoms through spring and summer.
A biodiversity action plan (BAP) is an internationally recognized program addressing threatened species and habitats and is designed to protect and restore biological systems. The original impetus for these plans derives from the 1992 Convention on Biological Diversity (CBD). As of 2009, 191 countries have ratified the CBD, but only a fraction of these have developed substantive BAP documents.
An IUCN Red List Critically Endangered 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. 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.
Platanthera yadonii, also known as Yadon's piperia or Yadon's rein orchid, is an endangered orchid endemic to a narrow range of coastal habitat in northern Monterey County, California. In 1998 this plant was designated as an endangered species by the United States government, the major threat to its survival being continuing land development from an expanding human population and associated habitat loss. One of the habitats of Yadon's piperia, the Del Monte Forest near Monterey, California, is the subject of a federal lawsuit, based upon endangerment of this organism along with several other endangered species.
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.
The green poison frog is a species of frog in the family Dendrobatidae. They are a small green colored frog, approximately 14-16 millimeters in size. Their color is a uniform green with brighter green back and legs, while the ventral side of the frog is metallic. It is endemic to the western slope of the Cordillera Occidental, Colombia.
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.
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.
Astragalus holmgreniorum is a rare species of milkvetch known by the common names Holmgren milk-vetch and paradox milk-vetch. It is native to a tiny section of desert shrub woodland on the border between Utah and Arizona, in the far northern Mojave Desert. There are six populations remaining. It is a federally listed endangered species.
Astragalus osterhoutii, or the Osterhout milkvetch or Kremmling milkvetch, is an endangered species of milkvetch, discovered and collected in 1905 at Sulfur Spring in Grand County Colorado by Colorado botanist George Everett Osterhout for which the plant was named. It is found in the U.S. state of Colorado, in a 13 kilometres (8.1 mi) radius near the town of Kremmling.
Cladonia perforata is a rare species of lichen known as Florida perforate cladonia and Florida perforate reindeer lichen. It is endemic to the state of Florida in the United States, where it is known from 16 populations in four widely separated areas of the state. It is native to a very specific type of Florida scrub habitat which is increasingly rare and patchy due to habitat destruction, degradation, and fragmentation. In 1993 this was the first species of lichen to be federally listed as an endangered species of the United States.
Pediocactus knowltonii is a rare species of cactus known by the common names Knowlton's miniature cactus, Knowlton's pincushion cactus, and Knowlton's minute cactus.
The splendid darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the Barren River system in south-central Kentucky and north-central Tennessee. This species is usually found in small rocky pools on the sides of creeks and rivers.
Ephedra coryi, also known as Cory's joint-fir, is a rare, reed-like gymnosperm native to sandy, semi-arid areas of the North American South and Southwest.
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.