Editing Local extinction

{{Short description|Termination of a taxon in a region which it previously inhabited}}
{{For|the excision or surgical destruction of a body part|Surgery}}
{{Use dmy dates|date=March 2021}}
'''Local extinction''', also '''extirpation''', is the termination of a [[species]] (or other [[taxon]]) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with [[extinction|global extinctions]].<ref>{{cite book|editor1-last=Ladle|editor1-first=Richard |editor2-first=Robert J. |editor2-last=Whittaker |title=Conservation Biogeography|url=https://archive.org/details/conservationbiog00ladl|url-access=limited|date=2011|publisher=John Wiley & Sons|isbn=978-1-4443-9811-3|page=[https://archive.org/details/conservationbiog00ladl/page/n72 61]}}</ref><ref name=smithpatten2015>{{cite journal | last1=Smith-Patten | first1=Brenda D. | last2=Bridge | first2=Eli S. | last3=Crawford | first3=Priscilla H. C. | last4=Hough | first4=Daniel J. | last5=Kelly | first5=Jeffrey F. | last6=Patten | first6=Michael A. |display-authors=2| title=Is extinction forever? | journal=[[Public Understanding of Science]]  | volume=24 | issue=4 | date=14 January 2015 | pages=481–495 | pmid=25711479 | doi=10.1177/0963662515571489 | pmc=4404403 }}</ref>

Local extinctions mark a change in the [[ecology]] of an area. It has sometimes been followed by a replacement of the species taken from other locations, such as with [[wolf reintroduction]].

==Discussion==
{{see also|Biogeography|Metapopulation|Patch dynamics|Habitat fragmentation}}
[[Glacial period|Glaciation]] is one factor that leads to local extinction. This was the case during the [[Quaternary glaciation|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.<ref>{{Cite journal|last=Gates|first=G. E.|date=May 1949|title=Miscellanea Megadrilogica|url=http://dx.doi.org/10.1086/281596|journal=The American Naturalist|volume=83|issue=810|pages=139–152|doi=10.1086/281596|s2cid=222328616|issn=0003-0147|url-access=subscription}}</ref>

Species naturally become extinct from islands over time; this can be either local extinction if the species also occurs elsewhere, or in cases of [[endemism|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]] 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 island]]s), 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).<ref>{{cite journal |last1=Diamond |first1=Jared M. |author-link1=Jared Diamond |date=November 1972 |title=Biogeographic Kinetics: Estimation of Relaxation Times for Avifaunas of Southwest Pacific Islands |url=http://jareddiamond.org/Jared_Diamond/Further_Reading_files/Diamond%201972_1.pdf |journal=[[Proceedings of the National Academy of Sciences of the USA]] |volume=69 |issue=11 |pages=3199–3203 |doi=10.1073/pnas.69.11.3199 |pmid=16592024 |pmc=389735 |bibcode=1972PNAS...69.3199D |access-date=21 November 2021|doi-access=free }}</ref><ref>{{cite journal |last1=Diamond |first1=Jared M. |author-link1=Jared Diamond |date=1975 |title=The Island Dilemma: Lessons of Modern Biogeographic Srudies for the Design of Natural Reserves |url=http://jareddiamond.org/Jared_Diamond/Further_Reading_files/Diamond%201975.pdf |journal=Biological Conservation |volume=7 |issue=2 |pages=129–146 |doi=10.1016/0006-3207(75)90052-X |bibcode=1975BCons...7..129D |access-date=21 November 2021}}</ref>

Some species exploit or require transient or [[disturbance (ecology)|disturbed]] habitats, such as vernal pools, a human gut, or burnt woodland after [[forest fire]]s, and are characterised by highly fluctuating population numbers and shifting distributional patterns. Many natural ecosystems cycle through a standard [[succession (ecology)|succession]], [[pioneer species]] disappear from a region as the ecosystem matures and reaches a [[climax community]].

A local extinction can be useful for research: in the case of the [[bay checkerspot butterfly]], scientists, including [[Paul R. Ehrlich]], chose not to intervene as a population disappeared from an area in order to study the process.<ref name="Holsinger">Holsinger, Kent.  "[http://darwin.eeb.uconn.edu/eeb310/lecture-notes/checkerspot/node4.html Local extinction] {{webarchive|url=https://web.archive.org/web/20070311042359/http://darwin.eeb.uconn.edu/eeb310/lecture-notes/checkerspot/node4.html |date=2007-03-11 }}". ''Population Viability Analysis: Bay Checkerspot Butterfly''. URL accessed August 11, 2006.</ref>

Many crocodilian species have experienced localized extinction, particularly the [[saltwater crocodile]] (''Crocodylus porosus''), which has been extirpated from Vietnam, Thailand, Java, and many other areas.<ref>{{Cite book|last1=Webb|first1=Grahame|url=https://d1wqtxts1xzle7.cloudfront.net/53234109/croc_2.pdf?1495471558=&response-content-disposition=inline%3B+filename%3DCroc.pdf&Expires=1617324076&Signature=RWpZNgowvcRiT5~eVvXnNiIu4T-dw9tkY6F5~IspzSAVjJ6E1BdwdQwbRi9ukFVPINwW8-SlFHgjrkICXZmo7PSqDHMdirdfTcVNmVSS2HtCLP7vE3ys3wvSiQlMPCvG0q~kvrEm9gY9V6BMD0mN41ek8JnlWKEk6yRdvsgthCCzW~886ei1uZngRClj33oltALQCo4rfymrxippXRT8Hhomz6JLz-cpYdA~1~w-lz~VcmVjMkArvumOvQ6K3yd6PK-h2nvcU5HFYniQGEMtR-XPLzFcPhOb5VE9kl01Wd2wYhTt3DmO0nrmHAyoQVLb86Jo9LpR8sDD0utKUCWjlw__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA|title=Saltwater Crocodile ''Crocodylus porosus''|last2=Manolis|first2=S|last3=Brien|first3=Matthew|publisher=Crocodiles|year=2010|pages=99–113}}{{dead link|date=May 2021|bot=medic}}{{cbignore|bot=medic}}</ref>

[[File:Wolf Canis lupus Wildpark Poing-09.jpg|thumb|''Canis lupus'']]

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.
[[File:Durvillaea potatorum Bull kelp P2153881.JPG|thumb|Bull Kelp]]
Heat waves can lead to local extinction. In New Zealand, during the summer of 2017–2018, [[sea surface temperature]]s around parts of [[South Island]] exceeded {{convert|23|C|abbr=on}}, which was well above normal. Air temperatures were also high, exceeding {{convert|30|C|abbr=on}}. These high temperatures, coupled with small wave height, led to the local extinction of [[Durvillaea|bull kelp (''Durvillaea'' spp.)]] from [[Lyttelton Harbour#Bays and headlands|Pile Bay]].<ref name=":0">{{Cite journal |last1=Thomsen|first1=Mads S. |last2=Mondardini |first2=Luca |last3=Alestra |first3=Tommaso |last4=Gerrity |first4=Shawn |last5=Tait |first5=Leigh |last6=South |first6=Paul M. |last7=Lilley |first7=Stacie A. |last8=Schiel |first8=David R. |name-list-style=amp |date=March 2019 |title=Local Extinction of Bull Kelp (''Durvillaea'' spp.) Due to a Marine Heatwave |journal=Frontiers in Marine Science |volume=6 |doi=10.3389/fmars.2019.00084 |issn=2296-7745 |doi-access=free}}</ref>

Lagoa Santa, a lake located in [[Lagoa Santa, Minas Gerais|Lagoa Santa, Brazil]], has lost almost 70% of the local fish species over the last 150 years. These include ''[[Acestrorhynchus lacustris]]'', ''[[Astyanax fasciatus]]'', and ''[[Characidium zebra]]''. This could be caused by the introduction of non-native species, like ''[[Redbreast tilapia|Tilapia rendalli]]'', into the lagoon, changes in water level and organic pollution.<ref>{{Cite journal|last1=Pompeu|first1=Paulo dos Santos|last2=Alves|first2=Carlos Bernardo Mascarenhas|date=December 2003|title=Local fish extinction in a small tropical lake in Brazil|journal=Neotropical Ichthyology|language=en|volume=1|issue=2|pages=133–135|doi=10.1590/S1679-62252003000200008|issn=1679-6225|doi-access=free}}</ref>

Local extinctions can be reversed, in some cases artificially. Wolves are a species that have been [[Reintroduction|reintroduced]] into parts of their historical range. This has happened with red wolves (''[[Red wolf|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.<ref>{{Cite journal|last1=Arts|first1=Koen|last2=Fischer|first2=Anke|last3=Wal|first3=René van der|date=2016|title=Boundaries of the wolf and the wild: a conceptual examination of the relationship between rewilding and animal reintroduction|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/rec.12309|journal=Restoration Ecology|language=en|volume=24|issue=1|pages=27–34|doi=10.1111/rec.12309|bibcode=2016ResEc..24...27A |s2cid=86338008|issn=1526-100X|url-access=subscription}}</ref>

==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]] (IUCN) has assessed the conservation status of the [[Black Sea]] stock of [[harbour porpoise]] (''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.<ref>[[IUCN Red List]], search for only stocks and subpopulations [http://www.iucnredlist.org/search/search.php?freetext=&modifier=phrase&criteria=wholedb&taxa_stock=1&Submit.x=0&Submit.y=0&redlistCategory%5B%5D=all&redlistAssessyear%5B%5D=all&country%5B%5D=all&aquatic%5B%5D=all&regions%5B%5D=all&habitats%5B%5D=all&threats%5B%5D=all]{{Dead link|date=August 2017}}</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]], North Pacific and North Atlantic stocks
* [[Bowhead whale]], ''Balaena mysticetus'' (five populations assessed, from critically endangered to [[LR/cd]])
* [[Lake sturgeon]], ''Acipenser fulvescens'', Mississippi & Missouri Basins population assessed as [[vulnerable species|vulnerable]]
* Wild [[common carp]], ''Cyprinus carpio'' (distribution in the River Danube)
* [[Black-flanked rock-wallaby]] ''Petrogale lateralis'' ([[MacDonnell Ranges]] 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]]
*[[Extinct in the wild]]

==References==
{{Reflist|30em}} 
{{Extinction}}

{{DEFAULTSORT:Local Extinction}}
[[Category:Extinction]]