AskDefine | Define extirpation

Dictionary Definition

extirpation

Noun

1 surgical removal of a body part or tissue [syn: ablation, cutting out, excision]
2 the act of pulling up or out; uprooting; cutting off from existence [syn: excision, deracination]

User Contributed Dictionary

English

Pronunciation

Noun

  1. The act of extirpating or uprooting.
    • 1748. David Hume. Enquiries concerning the human understanding and concerning the principles of moral. London: Oxford University Press, 1973. § 34.
      it aims at the correction of our manners, and extirpation of our vices

Translations

the act of extirparting
  • Portuguese: extirpação

Extensive Definition

Local extinction is where a species (or other taxon) ceases to exist in the chosen area of study, but still exists elsewhere. This phenomenon is also known as extirpation. Local extinctions are contrasted with global extinctions.
Local extinctions may be followed by a replacement of the species taken from other locations; wolf reintroduction is an example of this.

Conservation

Local extinctions mark a change in the ecology of an area.
The area of study chosen may reflect a natural subpopulation, political boundaries, or both. The Cetacean Specialist Group of the IUCN has assessed the threat of a local extinction of the Black Sea stock of Harbour Porpoise (Phocoena phocoena) which touches six different countries. COSWIC, by contrast, investigate wildlife only in Canada, so assesses only the risk of a Canadian local extinction even for species which cross into the United States or other countries. Other subpopulations may be naturally divided by political or country boundaries.
Often a subpopulation of a species will also be a subspecies. For example, the recent disappearance of the Black Rhinoceros (Diceros bicornis) from Cameroon spells not only the local extinction of rhinoceroses in Cameroon, but also the global extinction of the Western Black Rhinoceros (Diceros bicornis longipes).
In at least one case, scientists have found a local extinction useful for research: In the case of the Bay Checkerspot, scientists, including Paul R. Ehrlich, chose not to intervene in a local extinction, using it to study the danger to the world population However, similar studies are not carried out where a global population is at risk.

IUCN subpopulation and stock assessments

While the World Conservation Union (IUCN) mostly only categorizes whole species or subspecies, assessing the global risk of extinction, in some cases it also assesses the risks to stocks and populations, especially to preserve genetic diversity. In all, 119 stocks or subpopulations across 69 species have been assessed by the IUCN in 2006.
Examples of stocks and populations assessed by the IUCN for the threat of local extinction:
The IUCN also lists countries where assessed species, subspecies or subpopulations are found, and from which countries they have been extirpated or reintroduced.
The IUCN has only three entries for subpopulations which have become extinct the Aral Sea stock of Ship Sturgeon (Acipenser nudiventris); the Adriatic Sea stock of Beluga (Huso huso); and the Mexican subpopulation of Wolf (Canis lupus) which is extinct in the wild. No plant or fungi subpopulations have been assessed by the IUCN.

Local extinction events

Major environmental events, such as volcanic eruptions, may lead to large numbers of local extinctions, such as with the 1980 Mount St. Helens eruption, which led to a fern spike.

Paleontology

Paleontology often studies the replacement of one group of species with another, leading to the first group's local extinction.

External links

extirpation in French: Espèce extirpée
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