Conservation status |
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Extinct |
Threatened |
Lower Risk |
Other categories |
Related topics |
Comparison of Red List classes above and NatureServe status below |
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 genus, 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 of species and subspecies that are extinct in the wild include (in alphabetical order):
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]
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]
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]
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]
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]
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.
The Hawaiian crow or ʻalalā is a species of bird in the crow family, Corvidae, that is currently critically endangered, though reintroduction programs are underway. It is about the size of the carrion crow at 48–50 cm (19–20 in) in length, but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage and long, bristly throat feathers; the feet, legs, and bill are black. Today, the Hawaiian crow is considered the most endangered of the family Corvidae. They are recorded to have lived up to 18 years in the wild, and 28 years in captivity. Some Native Hawaiians consider the Hawaiian crow an ʻaumakua.
The Pinta Island tortoise, also known as the Pinta giant tortoise, Abingdon Island tortoise, or Abingdon Island giant tortoise, is a recently extinct subspecies of Galápagos tortoise native to Ecuador's Pinta Island.
Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the organism is capable of survival. The goal of species reintroduction is to establish a healthy, genetically diverse, self-sustaining population to an area where it has been extirpated, or to augment an existing population. Species that may be eligible for reintroduction are typically threatened or endangered in the wild. However, reintroduction of a species can also be for pest control; for example, wolves being reintroduced to a wild area to curb an overpopulation of deer. Because reintroduction may involve returning native species to localities where they had been extirpated, some prefer the term "reestablishment".
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).
The Galápagos tortoise or Galápagos giant tortoise is a very large species of tortoise in the genus Chelonoidis. The species comprises 15 subspecies. It is the largest living species of tortoise, and can weigh up to 417 kg (919 lb). They are also the largest extant terrestrial cold-blooded animals (ectotherms).
Translocation is the human action of moving an organism from one area and releasing it in another. In terms of wildlife conservation, its objective is to improve the conservation status of the translocated organism or to restore the function and processes of the ecosystem the organism is entering.
Achatinella apexfulva is an extinct species of colorful, tropical, arboreal pulmonate land snail in the family Achatinellidae, once present on Oahu, Hawaii. A. apexfulva is the type species of the genus Achatinella. The specific name, apexfulva, meaning "yellow-tipped", refers to the yellow tip of the snail's shell. Inspired from the taxon, the species has been given common names such as yellow-tipped Oʻahu tree snail or Hawaiian yellow-tipped tree snail. Officially, it is listed as ‘critically endangered’ by the IUCN, however, this is because its conservation status has not been updated in 28 years.
Partula suturalis, commonly called the moorean viviparous tree snail or the sutural partula, is a species of air-breathing tropical land snail, a terrestrial pulmonate gastropod mollusk in the family Partulidae. This species was endemic to the island of Moorea, French Polynesia. It is now extinct in the wild. It was previously listed as extinct in the IUCN Red List of Threatened Species, but has been moved to extinct in the wild since 2009. This error was the result of changing taxonomy.
Partula taeniata, common name the Moorean viviparous tree snail, is a species of terrestrial gastropod in the Partulidae family. It is endemic to French Polynesia.
Partula tohiveana, one of several species with the common name Moorean viviparous tree snail, is a species of air-breathing tropical land snail, a terrestrial pulmonate gastropod mollusk in the family Partulidae. This species is endemic to highlands on Moorea, French Polynesia.
An endling is the last known individual of a species or subspecies. Once the endling dies, the species becomes extinct. The word was coined in correspondence in the scientific journal Nature.
Partula is a genus of air-breathing tropical land snails, terrestrial pulmonate gastropod mollusks in the family Partulidae.
Lonesome George was a male Pinta Island tortoise and the last known individual of the subspecies. In his last years, he was known as the rarest creature in the world. George serves as an important symbol for conservation efforts in the Galápagos Islands and throughout the world.
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.
Chelonoidis niger donfaustoi, known as the eastern Santa Cruz tortoise, is a subspecies of Galápagos tortoise living on Santa Cruz Island, within the Galápagos. Until 2015, C. n. donfaustoi was considered conspecific with the western Santa Cruz tortoise, C. n. porteri.
Chelonoidis niger phantasticus is a subspecies of Galápagos tortoise that was discovered in 1906 and thought extinct, until a single female was discovered living on Fernandina Island by an expedition in February 2019. In May 2021, a genetic test carried out by scientists from the California Academy of Sciences confirmed that the single female tortoise discovered in 2019 is from the subspecies Chelonoidis niger phantasticus. The subspecies name has often been misspelled as phantastica, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
Chelonoidis niger vicina, commonly known as the Cerro Azul giant tortoise, Iguana Cove tortoise or the Isabela Island giant tortoise, is a subspecies of Galápagos tortoise endemic to Isabela Island in the Galápagos.
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