Editing Invasive species (section)

===Ecological===
The European Union defines "Invasive Alien Species" as those that are outside their natural distribution area, and that threaten [[biological diversity]].<ref>{{cite web |url=http://ec.europa.eu/environment/nature/invasivealien/docs/1_EN_resume_impact_assesment_part1_v3.pdf |title=Communication From The Commission To The Council, The European Parliament, The European Economic And Social Committee And The Committee Of The Regions Towards An EU Strategy On Invasive Species |access-date=May 17, 2011 |archive-date=March 5, 2016 |archive-url=https://web.archive.org/web/20160305033628/http://ec.europa.eu/environment/nature/invasivealien/docs/1_EN_resume_impact_assesment_part1_v3.pdf |url-status=live }}</ref><ref>{{cite journal |doi=10.2298/ZMSPN1834019L |title=Non-native and invasive tree species - their impact on biodiversity loss |year=2018 |last1=Lakicevic |first1=Milena |last2=Mladenovic |first2=Emina |journal=[[Zbornik Matice Srpske za Prirodne Nauke]] |issue=134 |pages=19–26 |doi-access=free}}</ref> Biotic invasion is one of the five top drivers for global [[biodiversity loss]], and is increasing because of tourism and [[globalization]].<ref>{{Cite book |url=https://www.nap.edu/read/10259/chapter/1 |year=2002 |doi=10.17226/10259 |pmid=25032288 |isbn=978-0-309-08264-8 |author1=National Research Council (US) Committee on the Scientific Basis for Predicting the Invasive Potential of Nonindigenous Plants Plant Pests in the United States |title=Predicting Invasions of Nonindigenous Plants and Plant Pests |access-date=November 17, 2019 |archive-date=November 17, 2019 |archive-url=https://web.archive.org/web/20191117204337/https://www.nap.edu/read/10259/chapter/1 |url-status=live}}</ref><ref>{{cite journal |doi=10.1038/nature14258 |title=Defining the Anthropocene |year=2015 |last1=Lewis |first1=Simon L. |last2=Maslin |first2=Mark A. |s2cid=205242896 |journal=[[Nature (journal) |Nature]] |volume=519 |issue=7542 |pages=171–180 |pmid=25762280 |bibcode=2015Natur.519..171L}}</ref> This may be particularly true in inadequately regulated [[fresh water]] systems, though [[quarantine]]s and [[ballast water]] rules have improved the situation.<ref>{{cite web |url=http://www.millenniumassessment.org/documents/document.354.aspx.pdf |title=Ecosystems and Human Well-being: Biodiversity Synthesis |author=Millennium Ecosystem Assessment |year=2005 |publisher=[[World Resources Institute]] |author-link=Millennium Ecosystem Assessment |access-date=September 18, 2007 |archive-date=October 14, 2019 |archive-url=https://web.archive.org/web/20191014033601/http://www.millenniumassessment.org/documents/document.354.aspx.pdf |url-status=live}}</ref>

[[File:Gator and Python.jpg |thumb |right |[[American alligator]] combatting a [[Burmese python in Florida |Burmese python]] in Florida ]]

Invasive species may drive local native species to extinction via [[Competition (biology) |competitive]] exclusion, [[Ecological niche |niche]] displacement, or [[hybrid (biology) |hybrid]]isation with related native species. Therefore, besides their economic ramifications, alien invasions may result in extensive changes in the structure, composition and global distribution of the biota at sites of introduction, leading ultimately to the homogenisation of the world's fauna and flora and the [[loss of biodiversity]].<ref>{{cite journal |doi=10.1098/rspb.2012.1651 |title=Pattern and process of biotic homogenization in the New Pangaea |year=2012 |last1=Baiser |first1=Benjamin |last2=Olden |first2=Julian D. |last3=Record |first3=Sydne |last4=Lockwood |first4=Julie L. |last5=McKinney |first5=Michael L. |journal=[[Proceedings of the Royal Society B: Biological Sciences]] |volume=279 |issue=1748 |pages=4772–4777 |pmid=23055062 |pmc=3497087}}</ref><ref name="Odendaal 2008">{{cite journal |last1=Odendaal |first1=L. J. |last2=Haupt |first2=T. M. |last3=Griffiths |first3=C. L. |year=2008 |title=The alien invasive land snail ''Theba pisana'' in the West Coast National Park: Is there cause for concern? |journal=[[Koedoe]] |volume=50 |issue=1 |pages=93–98 |doi=10.4102/koedoe.v50i1.153 |doi-access=free }}</ref> It is difficult to unequivocally attribute extinctions to a species invasion, though there is for example strong evidence that the extinction of about 90 amphibian species was caused by the [[chytridiomycosis|chytrid fungus]] spread by international trade.<ref>{{cite journal |doi=10.1038/s41579-020-0335-x |title=Chytrid fungi and global amphibian declines |year=2020 |last1=Fisher |first1=Matthew C. |last2=Garner |first2=Trenton W. J. |s2cid=211266075 |journal=[[Nature Reviews Microbiology]] |volume=18 |issue=6 |pages=332–343 |pmid=32099078 |url=https://discovery.ucl.ac.uk/id/eprint/10092667/1/NRMICRO-19-244_FINAL_ACCEPTED.pdf |hdl=10044/1/78596 |hdl-access=free |access-date=September 28, 2020 |archive-date=November 7, 2020 |archive-url=https://web.archive.org/web/20201107202307/https://discovery.ucl.ac.uk/id/eprint/10092667/1/NRMICRO-19-244_FINAL_ACCEPTED.pdf |url-status=live}}</ref>

Multiple successive introductions of different non-native species can worsen the total effect, as with the introductions of the [[amethyst gem clam]] and the [[Carcinus maenas|European green crab]]. The gem clam was introduced into California's [[Bodega Bay|Bodega Harbor]] from the US East Coast a century ago. On its own, it never displaced native clams (''Nutricola'' spp.). In the mid-1990s, the introduction of the European green crab resulted in an increase of the amethyst gem at the expense of the native clams.<ref>{{cite journal |last=Grosholz |first=E.D. |year=2005 |title=Recent biological invasion may hasten invasional meltdown by accelerating historical introductions |journal=[[Proceedings of the National Academy of Sciences]] |volume=102 |pages=1088–1091 |doi=10.1073/pnas.0308547102 |pmid=15657121 |issue=4 |pmc=545825 |bibcode=2005PNAS..102.1088G |doi-access=free }}</ref> In India, multiple invasive plants  have invaded 66% of natural areas, reducing the densities of native forage plants, declining the habitat-use by wild herbivores and threatening the long-term sustenance of dependent carnivores, including the [[tiger]].<ref>{{Cite journal |last=Mungi |first=Ninad Avinash |title=Distribution, drivers and restoration priorities of plant invasions in India |journal=Journal of Applied Ecology |date=2023 |volume=60 |issue=11 |pages=2400–2412|doi=10.1111/1365-2664.14506 |bibcode=2023JApEc..60.2400M |doi-access=free }}</ref><ref>{{Cite journal |last=Rastogi |first=Rajat |title=Multiple invasions exert combined magnified effects on native plants, soil nutrients and alters the plant-herbivore interaction in dry tropical forest |url=https://www.sciencedirect.com/science/article/pii/S0378112723000142 |journal=Forest Ecology and Management |date=2023 |volume=531 |pages=120781|doi=10.1016/j.foreco.2023.120781 |bibcode=2023ForEM.53120781R }}</ref>

Invasive species can change the functions of ecosystems. For example, invasive plants can alter the [[fire regime]] (cheatgrass, ''[[Drooping Brome |Bromus tectorum]]''), [[nutrient cycling]] (smooth cordgrass ''[[Spartina alterniflora]]''), and hydrology (''[[Tamarix]]'') in native ecosystems.<ref name = causesepidemiology /> Invasive species that are closely related to rare native species have the potential to hybridize with the native species. Harmful effects of hybridization have led to a decline and even extinction of native species.<ref>{{cite journal |last=Hawkes |first=C.V. |year=2005 |title=Plant invasion alters nitrogen cycling by modifying the soil nitrifying community |journal=[[Ecology Letters]] |volume=8 |pages=976–985 |doi=10.1111/j.1461-0248.2005.00802.x |issue=9 |pmid=34517683 |bibcode=2005EcolL...8..976H }}</ref><ref name="rhymer">{{cite journal |last=Rhymer |first=J. M. |author2=Simberloff, D. |year=1996 |title=Extinction by hybridization and introgression |journal=[[Annual Review of Ecology and Systematics]] |issue=1 |pages=83–109 |doi=10.1146/annurev.ecolsys.27.1.83 |volume=27|bibcode=1996AnRES..27...83R }}</ref> For example, [[Hybridization (biology) |hybridization]] with introduced cordgrass, ''Spartina alterniflora'', threatens the existence of California cordgrass (''[[Spartina foliosa]]'') in [[San Francisco Bay]].<ref name="ayres">{{cite journal |last=Ayres |first=D. |s2cid=24732543 |year=2004 |title=Spread of exotic cordgrasses and hybrids (''Spartina'' sp.) in the tidal marshes of San Francisco Bay, California, USA |journal=[[Biological Invasions]] |volume=6 |pages=221–231 |doi=10.1023/B:BINV.0000022140.07404.b7 |issue=2 |bibcode=2004BiInv...6..221A |display-authors=etal}}</ref> Invasive species cause competition for native species and because of this 400 of the 958 endangered species under the [[Endangered Species Act of 1973 |Endangered Species Act]] are at risk.<ref>{{cite journal |last=Primtel |first=David |year=2005 |title=Update on the environmental and economic costs associated with alien-invasive species in the United States |journal=[[Ecological Economics (journal) |Ecological Economics]] |volume=52 |issue=3 |pages=273–288 |doi=10.1016/j.ecolecon.2004.10.002|bibcode=2005EcoEc..52..273P }}</ref>

[[File:Firewoodposter white web.pdf |thumb |left |Poster from the [[Government of California|State of California]] asking campers to not move firewood around, avoiding the spread of invasive species]]

The unintentional introduction of forest pest species and plant pathogens can change [[forest ecology]] and damage the [[timber industry]]. Overall, [[forest ecosystem]]s in the U.S. are widely invaded by exotic pests, plants, and pathogens.<ref>{{cite journal |last1=Liebhold |first1=S. |year=2013 |title=A highly aggregated geographical distribution of forest pest invasions in the USA |doi=10.1111/ddi.12112 |journal=[[Diversity and Distributions]] |volume=19 |issue=9 |pages=1208–1216 |s2cid=85799394 |display-authors=etal |doi-access=free |bibcode=2013DivDi..19.1208L }}</ref><ref>{{cite journal |last1=Oswalt |first1=C. |year=2015 |title=A subcontinental view of forest plant invasions |journal=[[NeoBiota]] |volume=24 |pages=49–54 |display-authors=etal |doi=10.3897/neobiota.24.8378 |doi-access=free }}</ref>

The Asian long-horned beetle (''[[Anoplophora glabripennis]]'') was first introduced into the U.S. in 1996, and was expected to infect and damage millions of acres of hardwood trees. As of 2005 thirty million dollars had been spent in attempts to eradicate this pest and protect millions of trees in the affected regions.<ref name="pimental"/> The [[woolly adelgid]] has inflicted damage on old-growth spruce, fir and [[Tsuga |hemlock]] forests and damages the [[Christmas tree]] industry.<ref>{{Cite web |title=South/Adelges piceae - Bugwoodwiki |url=https://wiki.bugwood.org/Archive:South/Balsam_Woolly_Aphid |url-status=live |archive-url=https://web.archive.org/web/20110722063118/http://wiki.bugwood.org/Archive:South/Balsam_Woolly_Aphid |archive-date=22 July 2011 |access-date=2022-06-26 |website=wiki.bugwood.org}}</ref>  [[Chestnut blight]] and [[Dutch elm disease]] are plant pathogens with serious impacts.<ref>Schlarbaum, Scott E., Frederick Hebard, Pauline C. Spaine, and Joseph C. Kamalay. (1998) [https://www.fs.usda.gov/treesearch/pubs/745 "Three American Tragedies: Chestnut Blight, Butternut Canker, and Dutch Elm Disease'] {{Webarchive |url=https://web.archive.org/web/20200113231820/https://www.fs.usda.gov/treesearch/pubs/745 |date=January 13, 2020 }}. In: Britton, Kerry O., Ed. Exotic Pests of Eastern Forests Conference Proceedings; 1997 April 8–10; Nashville, TN. U.S. Forest Service and Tennessee Exotic Pest Plant Council., pp. 45–54.</ref><ref name="USDA-Forest Service-Schlarbaum-1997">{{cite web |author1=Schlarbaum, Scott E. |author2=Hebard, Frederick |author3=Spaine, Pauline C. |author4=Kamalay, Joseph C. |url=http://www.srs.fs.usda.gov/pubs/ja/ja_schlarbaum002.htm |title=Three American Tragedies: Chestnut Blight, Butternut Canker and Dutch Elm Disease |publisher=Southern Research Station, [[United States Forest Service |Forest Service]], [[United States Department of Agriculture]] |year=1997 |work=(originally published via: Proceedings: Exotic Pests of Eastern Forests; (1997 April 8–10); Nashville, TN. Tennessee Exotic Pest Plant Council: 45–54.) |access-date=June 22, 2012 |archive-date=April 24, 2012 |archive-url=https://web.archive.org/web/20120424101943/http://www.srs.fs.usda.gov/pubs/ja/ja_schlarbaum002.htm |url-status=live }} <br />
Alternative link and additional publication citation information: Tree Search, US Forest Service, USDA. [http://www.treesearch.fs.fed.us/pubs/745 http://www.treesearch.fs.fed.us/pubs/745] {{Webarchive |url=https://web.archive.org/web/20121123093613/http://www.treesearch.fs.fed.us/pubs/745 |date=November 23, 2012 }}</ref> Garlic mustard, ''[[Alliaria petiolata]]'', is one of the most problematic invasive plant species in eastern North American forests, where it is highly invasive of the [[understory]], reducing the growth rate of tree seedlings and threatening to modify the forest's tree composition.<ref>{{cite journal |last1=Rodger |first1=Vikki |last2=Stinson |first2=Kristin |last3=Finzi |first3=Adrian |year=2008 |title=Ready or Not, Garlic Mustard Is Moving In: ''Alliaria petiolata'' as a Member of Eastern North American Forests |doi=10.1641/b580510 |journal=[[BioScience]] |volume=58 |issue=5 |page=5 |doi-access=free }}</ref>

Native [[species]] can be threatened with [[extinction]]<ref name=":1">{{cite journal |pmc=33232 |title=The evolutionary impact of invasive species |year=2001 |volume=98 |issue=10 |pmid=11344292 |last1=Mooney |first1=HA |last2=Cleland |first2=EE |pages=5446–51 |doi=10.1073/pnas.091093398 |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |bibcode=2001PNAS...98.5446M |doi-access=free }}</ref> through the process of [[genetic pollution]]. Genetic pollution is unintentional [[Hybrid (biology) |hybridization]] and [[introgression]], which leads to homogenization or replacement of local [[genotypes]] as a result of either a numerical or [[Fitness (biology) |fitness]] advantage of the introduced species.<ref>{{cite web |url=http://www.nativeseednetwork.org/article_view?id=13 |title=Glossary: definitions from the following publication: Aubry, C., R. Shoal and V. Erickson. 2005. Grass cultivars: their origins, development, and use on national forests and grasslands in the Pacific Northwest. USDA Forest Service. 44 pages, plus appendices.; Native Seed Network (NSN), Institute for Applied Ecology, 563 SW Jefferson Ave, Corvallis, OR 97333, USA |publisher=Nativeseednetwork.org |access-date=May 17, 2011 |archive-url=https://web.archive.org/web/20060222092651/http://www.nativeseednetwork.org/article_view?id=13 |archive-date=February 22, 2006 }}</ref> Genetic pollution occurs either through introduction or through habitat modification, where previously isolated species are brought into contact with the new genotypes. Invading species have been shown to adapt to their new environments in a remarkably short amount of time.<ref name=":1"/> The population size of invading species may remain small for a number of years and then experience an explosion in population, a phenomenon known as "the lag effect".<ref name = causesepidemiology >{{cite journal |last1=Mack |first1=Richard N. |last2=Simberloff |first2=Daniel |author2-link=Daniel Simberloff |last3=Mark Lonsdale |first3=W. |last4=Evans |first4=Harry |last5=Clout |first5=Michael |last6=Bazzaz |first6=Fakhri A. |title=Biotic Invasions: Causes, Epidemiology, Global Consequences, and Control |journal=Ecological Applications |date=June 2000 |volume=10 |issue=3 |pages=689–710 |doi=10.1890/1051-0761(2000)010[0689:BICEGC]2.0.CO;2 |s2cid=711038 }}</ref>

[[File:Linepithema Argentine ant.jpg|thumb|[[Argentine ant]]s, which form [[Ant supercolony|supercolonies]] across continents, are ranked among the [[100 of the World's Worst Invasive Alien Species|world's 100&nbsp;worst invasive animal species]].<ref>{{cite report
 |last1=Boudjelas |first1=Souyad
 |year=2000
 |title=100 of the world's worst invasive alien species
 |website=iucn.org
 |publisher=[[International Union for Conservation of Nature]]
 |url=https://portals.iucn.org/library/sites/library/files/documents/2000-126.pdf
 |access-date=20 July 2018
}}
</ref>]]
Hybrids resulting from invasive species interbreeding with native species can incorporate their genotypes into the gene pool over time through [[introgression]]. Similarly, in some instances a small invading population can threaten much larger native populations. For example, ''[[Spartina alterniflora]]'' was introduced in the San Francisco Bay and hybridized with native ''[[Spartina foliosa]].'' The higher pollen count and male fitness of the invading species resulted in [[introgression]] that threatened the native populations due to lower pollen counts and lower viability of the native species.<ref>{{cite journal |title=Reciprocal hybrid formation of Spartina in San Francisco Bay |journal=[[Molecular Ecology]] |volume=9 |issue=6 |pages=765–770 |doi=10.1046/j.1365-294x.2000.00935.x |pmid=10849292 |year=2000 |last1=Anttila |first1=C. K. |last2=King |first2=R. A. |last3=Ferris |first3=C. |last4=Ayres |first4=D. R. |last5=Strong |first5=D. R. |bibcode=2000MolEc...9..765A |s2cid=32865913}}</ref> Reduction in fitness is not always apparent from [[Morphology (biology) |morphological]] observations alone. Some degree of [[gene flow]] is normal, and preserves constellations of [[gene]]s and genotypes.<ref name="rhymer"/><ref>{{Cite book |url=http://www.rirdc.gov.au/reports/AFT/01-114.pdf |title=Genetic Pollution from Farm Forestry using eucalypt species and hybrids; A report for the RIRDC/L&WA/FWPRDC]; Joint Venture Agroforestry Program; by Brad M. Potts, Robert C. Barbour, Andrew B. Hingston; September 2001; RIRDC Publication No 01/114; RIRDC Project No CPF – 3A; |year=2001 |isbn=978-0-642-58336-9 |publisher=Australian Government, Rural Industrial Research and Development Corporation |access-date=April 22, 2017 |archive-url=https://web.archive.org/web/20040102175403/http://www.rirdc.gov.au/reports/AFT/01-114.pdf |archive-date=January 2, 2004 }}</ref> An example of this is the interbreeding of migrating [[coyote]]s with the [[red wolf]], in areas of eastern [[North Carolina]] where the [[red wolf]] was reintroduced, reducing red wolf numbers.<ref>{{cite journal |doi=10.1016/j.biocon.2015.01.013 |title=Factors influencing red wolf–coyote hybridization in eastern North Carolina, USA |journal=[[Biological Conservation]] |volume=184 |pages=108–116 |year=2015 |last1=Bohling |first1=Justin H. |last2=Waits |first2=Lisette P.|bibcode=2015BCons.184..108B }}</ref>