Local extinction, also extirpation, is the termination of a
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
(or other
taxon
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with
global extinctions.
Local extinctions mark a change in the
ecology
Ecology () is the natural science of the relationships among living organisms and their Natural environment, environment. Ecology considers organisms at the individual, population, community (ecology), community, ecosystem, and biosphere lev ...
of an area. It has sometimes been followed by a replacement of the species taken from other locations, such as with
wolf reintroduction
Wolf reintroduction involves the reintroduction of a portion of grey wolves in areas where native wolves have been extirpated. More than 30 subspecies of ''Canis lupus'' have been recognized, and grey wolves, as colloquially understood, compr ...
.
Discussion
Glaciation
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...
is one factor that leads to local extinction. This was the case during the
Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe.
Species naturally become extinct from islands over time; this can be either local extinction if the species also occurs elsewhere, or in cases of
island endemism, outright extinction. The number of species an island can support is limited by its geographical size. Because many islands were relatively recently formed due to climate change at the end of the
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
when the sea level rose, and these islands most likely had the same complement of species as found on the mainland, counting the species which still survive at present on a statistically large enough amount of islands will give the parameters with which certain groups of species such as plants or birds will become less biodiverse on a given island over a given period of time, depending on its size. The same calculations can also be applied to determine when species will disappear from nature parks ('islands' in many senses), mountain tops and mesas (see
sky islands), forest remnants or other such distributional patches. This research also demonstrates that certain species are more prone to extinction than others, a species has an intrinsic extinction-ability (incidence function).
Some species exploit or require transient or
disturbed habitats, such as vernal pools, a human gut, or burnt woodland after
forest fire
A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire ( in Australia), dese ...
s, and are characterised by highly fluctuating population numbers and shifting distributional patterns. Many natural ecosystems cycle through a standard
succession
Succession is the act or process of following in order or sequence.
Governance and politics
*Order of succession, in politics, the ascension to power by one ruler, official, or monarch after the death, resignation, or removal from office of ...
,
pioneer species
Pioneer species are resilient species that are the first to colonize barren environments, or to repopulate disrupted biodiverse steady-state ecosystems as part of ecological succession. Various kinds of events can create good conditions for pi ...
disappear from a region as the ecosystem matures and reaches a
climax community
In scientific ecology, climax community or climatic climax community is a historic term for a community of plants, animals, and fungi which, through the process of ecological succession in the development of vegetation in an area over time, hav ...
.
A local extinction can be useful for research: in the case of the
bay checkerspot butterfly
The Bay checkerspot (''Euphydryas editha bayensis'') is a butterfly endemic to the San Francisco Bay region of the U.S. state of California. It is a federally threatened species, as a subspecies of '' Euphydryas editha''.
Since the 1980s the p ...
, scientists, including
Paul R. Ehrlich, chose not to intervene as a population disappeared from an area in order to study the process.
[Holsinger, Kent. ]
Local extinction
". ''Population Viability Analysis: Bay Checkerspot Butterfly''. URL accessed August 11, 2006.
Many crocodilian species have experienced localized extinction, particularly the
saltwater crocodile
The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaland to northern Australia and Micronesia. It ha ...
(''Crocodylus porosus''), which has been extirpated from Vietnam, Thailand, Java, and many other areas.

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 extinction.

Heat waves can lead to local extinction. In New Zealand, during the summer of 2017–2018,
sea surface temperature
Sea surface temperature (or ocean surface temperature) is the ocean temperature, temperature of ocean water close to the surface. The exact meaning of ''surface'' varies in the literature and in practice. It is usually between and below the sea ...
s around parts of
South Island
The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...
exceeded , which was well above normal. Air temperatures were also high, exceeding . These high temperatures, coupled with small wave height, led to the local extinction of
bull kelp (''Durvillaea'' spp.) from
Pile Bay.
Lagoa Santa, a lake located in
Lagoa Santa, Brazil, has lost almost 70% of the local fish species over the last 150 years. These include ''
Acestrorhynchus lacustris
''Acestrorhynchus lacustris'' is a species of fish in the family Acestrorhynchidae. It was described by Christian Frederik Lütken in 1875, originally under the genus '' Xiphorhamphus''. It inhabits the São Francisco and Paraná River. It reach ...
'', ''
Astyanax fasciatus
''Psalidodon fasciatus'', commonly known as the banded astyanax, is a species of fish widespread in the Americas
The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South Americ ...
'', and ''
Characidium zebra''. This could be caused by the introduction of non-native species, like ''
Tilapia rendalli'', into the lagoon, changes in water level and organic pollution.
Local extinctions can be reversed, in some cases artificially. Wolves are a species that have been
reintroduced into parts of their historical range. This has happened with red wolves (''
Canis rufus'') in the United States in the late 1980s and also grey wolves in Yellowstone National Park in the mid-1990s. There have been talks of reintroducing wolves in Scotland, Japan, and Mexico.
Subpopulations and stocks
When the local population of a certain species disappears from a certain geographical delimitation, whether fish in a drying pond or an entire ocean, it can be said to be extirpated or locally extinct in that pond or ocean.
A particular total world population can be more or less arbitrarily divided into 'stocks' or 'subpopulations', defined by political or other geographical delimitations. For example, the Cetacean Specialist Group of the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN) has assessed the conservation status of the
Black Sea
The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
stock of
harbour porpoise
The harbour porpoise (''Phocoena phocoena'') is one of eight extant species of porpoise. It is one of the smallest species of cetacean. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar ...
(''Phocoena phocoena'') that touches six countries, and
COSEWIC, which only assesses the conservation status of wildlife in Canada, even assesses Canadian species that occur in the United States or other countries.
While the IUCN mostly only assesses the global conservation status of species or subspecies, in some older cases it also assessed the risks to certain stocks and populations, in some cases these populations may be genetically distinct. In all, 119 stocks or subpopulations across 69 species had been assessed by the IUCN in 2006.
IUCN Red List
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 ...
, search for only stocks and subpopulation
/ref> If a local stock or population becomes extinct, the species as a whole has not become extinct, but extirpated from that local area.
Examples of stocks and subdivisions of world populations assessed separately by the IUCN for their conservation status are:
* Marsh deer (three populations assessed)
* Blue whale
The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known ever to have existed. The blue whale's long and slender body can ...
, North Pacific and North Atlantic stocks
* Bowhead whale
The bowhead whale (''Balaena mysticetus''), sometimes called the Greenland right whale, Arctic whale, and polar whale, is a species of baleen whale belonging to the family Balaenidae and is the only living representative of the genus '' Balaena' ...
, ''Balaena mysticetus'' (five populations assessed, from critically endangered to LR/cd)
* Lake sturgeon
The lake sturgeon (''Huso fulvescens''), also known as the rock sturgeon, is a North American temperate freshwater fish, one of 27 species of sturgeon. Like other sturgeons, this species is a bottom feeder and has a partly cartilaginous skele ...
, ''Acipenser fulvescens'', Mississippi & Missouri Basins population assessed as vulnerable
* Wild common carp
The common carp (''Cyprinus carpio''), also known as European carp, Eurasian carp, or simply carp, is a widespread freshwater fish of eutrophic waters in lakes and large rivers in Europe and Asia.Fishbase''Cyprinus carpio'' Linnaeus, 1758/ref>Ark ...
, ''Cyprinus carpio'' (distribution in the River Danube)
* Black-flanked rock-wallaby ''Petrogale lateralis'' (MacDonnell Ranges
The MacDonnell Ranges, or Tjoritja in Arrernte language, Arrernte, is a mountain range located in southern Northern Territory. MacDonnell Ranges is also the name given to an Interim Biogeographic Regionalisation for Australia, interim Australia ...
population and Western Kimberly population)
The IUCN also lists countries where assessed species, subspecies or geographic populations are found, and from which countries they have been extirpated or reintroduced.
See also
* List of extinct animals
*Threatened species
A threatened species is any species (including animals, plants and fungi) which is vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensatio ...
* Extinct in the wild
References
{{DEFAULTSORT:Local Extinction
Extinction