Editing Invasive species (section)

==Adverse effects==
Invasive species can affect the invaded habitats and bioregions adversely, causing ecological, environmental, or economic damage.{{r|ehrenfeld2010}}

===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>

=== Environmental ===
In South Africa's Cape Town region, analysis demonstrated that the restoration of priority source water sub-catchments through the removal of thirsty alien plant invasions (such as Australian acacias, pines and eucalyptus, and Australian black wattle) would generate expected annual water gains of 50 billion liters within 5 years compared to the business-as-usual scenario (which is important as Cape Town experiences significant [[water scarcity]]). This is the equivalent to one-sixth of the city's current supply needs. These annual gains will double within 30 years. The catchment restoration is significantly more cost-effective then other water augmentation solutions (1/10 the unit cost of alternative options).<ref>{{Cite web |title=Cape Town is Facing Day Zero |url=https://www.nature.org/en-us/about-us/where-we-work/africa/stories-in-africa/cape-town-faces--day-zero-/ |access-date=2023-11-06 |website=The Nature Conservancy}}</ref> A water fund has been established, and these exotic species are being eradicated.<ref>{{Cite web |url=https://www.nature.org/content/dam/tnc/nature/en/documents/GCTWF-summary-11.14.18.pdf |title=Greater cape town water fund |access-date=November 16, 2020 |archive-date=February 28, 2021 |archive-url=https://web.archive.org/web/20210228175854/https://www.nature.org/content/dam/tnc/nature/en/documents/GCTWF-summary-11.14.18.pdf |url-status=live}}</ref>

=== Human health ===
Invasive species can affect human health. With the alteration in ecosystem functionality (due to homogenization of biota communities), invasive species have resulted in negative effects on human well-being, which includes reduced resource availability, unrestrained spread of human diseases, recreational and educational activities, and tourism.<ref name=":8">{{cite journal |last1=Mazza |first1=G. |last2=Tricarico |first2=E. |last3=Genovesi |first3=P. |last4=Gherardi |first4=F. |title=Biological invaders are threats to human health: an overview |journal=Ethology Ecology & Evolution |volume=26 |issue=2–3 |date=2013-12-19 |doi=10.1080/03949370.2013.863225 |pages=112–129|s2cid=58888740 }}</ref><ref name=":22">{{Cite journal |last1=Pyšek |first1=P. |last2=Richardson |first2=D.M. |date=2010 |title=Invasive Species, Environmental Change and Management, and Health |journal=Annual Review of Environment and Resources |volume=35 |issue=1 |pages=25–55 |doi=10.1146/annurev-environ-033009-095548 |doi-access=free}}</ref> Alien species have caused diseases including [[HIV|human immunodeficiency virus]] (HIV), [[Monkeypox|monkey pox]], and [[severe acute respiratory syndrome]] (SARS).<ref name=":22"/>

Invasive species and accompanying control efforts can have long term [[public health]] implications. For instance, [[pesticide]]s applied to treat a particular pest species could pollute soil and surface water.<ref name="pimental"/> Encroachment of humans into previously remote ecosystems has exposed exotic diseases such as [[HIV]] to the wider population.<ref name="pimental"/> Introduced birds (e.g. [[pigeons]]), rodents and insects (e.g. [[mosquito]], [[flea]], [[louse]] and [[tsetse fly]] pests) can serve as vectors and reservoirs of human afflictions. Throughout recorded history, epidemics of human diseases, such as [[malaria]], [[yellow fever]], [[typhus]], and [[bubonic plague]], spread via these vectors.<ref name="elton"/> A recent example of an introduced disease is the spread of the [[West Nile virus]], which killed humans, birds, mammals, and reptiles.<ref>{{cite journal |last1=Lanciotti |first1=R. S. |last2=Roehrig |first2=J. T. |last3=Deubel |first3=V. |last4=Smith |first4=J. |last5=Parker |first5=M. |last6=Steele |first6=K. |last7=Crise |first7=B. |last8=Volpe |first8=K. E. |last9=Crabtree |first9=M. B. |last10=Scherret |first10=J. H. |last11=Hall |first11=R. A. |last12=MacKenzie |first12=J. S. |last13=Cropp |first13=C. B. |last14=Panigrahy |first14=B. |last15=Ostlund |first15=E. |date=17 December 1999 |title=Origin of the West Nile Virus Responsible for an Outbreak of Encephalitis in the Northeastern United States |journal=Science |volume=286 |issue=5448 |pages=2333–2337 |doi=10.1126/science.286.5448.2333 |pmid=10600742 |last16=Schmitt |first16=B. |last17=Malkinson |first17=M. |last18=Banet |first18=C. |last19=Weissman |first19=J. |last20=Komar |first20=N. |last21=Savage |first21=H. M. |last22=Stone |first22=W. |last23=McNamara |first23=T. |last24=Gubler |first24=D. J. |display-authors=6}}</ref> The introduced [[Chinese mitten crab]]s are carriers of [[Paragonimus westermani|Asian lung fluke]].{{r|pnwaquaticinv}} Waterborne disease agents, such as [[cholera]] bacteria (''[[Vibrio cholerae]]''), and causative agents of [[harmful algal bloom]]s are often transported via ballast water.<ref>{{cite journal |last=Hallegraeff |first=G.M. |year=1998 |title=Transport of toxic dinoflagellates via ships' ballast water: Bioeconomic risk assessment and efficacy of possible ballast water management strategies |journal=[[Marine Ecology Progress Series]] |volume=168 |pages=297–309 |bibcode=1998MEPS..168..297H |doi=10.3354/meps168297 |doi-access=free}}</ref>

=== Economic ===
[[File:Pasig River Intramuros Escolta Water Hyacinths.jpg|thumb|Invasive [[water hyacinth]]s clog the [[Pasig River]] in [[Manila]], [[Philippines]] in October 2020.<ref>{{cite news |last1=Dela Cruz |first1=Raymond Carl |title=Water hyacinths ground Pasig River Ferry ops |url=https://www.pna.gov.ph/articles/1117832 |access-date=10 August 2024 |work=[[Philippine News Agency]] |date=October 7, 2020 |archive-url=https://web.archive.org/web/20231028150214/https://www.pna.gov.ph/articles/1117832 |archive-date=October 28, 2023}}</ref>]]

Globally, invasive species management and control are substantial economic burdens, with expenditures reaching approximately $1.4 trillion annually.{{r|amstutz2018}} The economic impact of invasive alien species alone was estimated to exceed $423 billion annually as of 2019. This cost has exhibited a significant increase, quadrupling every decade since 1970, underscoring the escalating financial implications of these biological invasions.<ref>{{Cite web |last=Environment |first=U. N. |date=2023-09-04 |title=Invasive Alien Species Report |url=http://www.unep.org/resources/report/invasive-alien-species-report |access-date=2024-05-29 |website=www.unep.org |language=en}}</ref>

Invasive species contribute to [[Environmental degradation|ecological degradation]], altering ecosystem functionality and reducing the services ecosystems provide. This necessitates additional expenditures to control the spread of biological invasions, mitigate further impacts, and restore affected ecosystems. For example, the damage caused by 79 invasive species between 1906 and 1991 in the United States has been estimated at US$120 billion. Similarly, in [[China]], invasive species have been reported to reduce the country's gross domestic product (GDP) by 1.36% per year.<ref name=":22" /><ref>{{cite journal |last1=Xu |first1=Haigen |last2=Ding |first2=Hui |last3=Li |first3=Mingyan |last4=Qiang |first4=Sheng |last5=Guo |first5=Jianying |last6=Han |first6=Zhengmin |last7=Huang |first7=Zongguo |last8=Sun |first8=Hongying |last9=He |first9=Shunping |last10=Wu |first10=Hairong |last11=Wan |first11=Fanghao |date=2006 |title=The distribution and economic losses of alien species invasion to China |journal=Biological Invasions |volume=8 |issue=7 |pages=1495–1500 |bibcode=2006BiInv...8.1495X |doi=10.1007/s10530-005-5841-2 |s2cid=25890246}}</ref>

The management of biological invasions can be costly. In [[Australia]], for instance, the expense to monitor, control, manage, and research invasive weed species is approximately AU$116.4 million per year, with costs directed solely to central and local government.<ref name=":22" />

While in some cases, invasive species may offer economic benefits, such as the potential for commercial forestry from invasive trees, these benefits are generally overshadowed by the substantial costs associated with biological invasions. In most cases, the [[Returns (economics)|economic returns]] from invasive species are far less than the costs they impose.<ref name=":32">{{cite journal |last1=Molnar |first1=Jennifer L |last2=Gamboa |first2=Rebecca L |last3=Revenga |first3=Carmen |last4=Spalding |first4=Mark D |date=2008 |title=Assessing the global threat of invasive species to marine biodiversity |journal=Frontiers in Ecology and the Environment |volume=6 |issue=9 |pages=485–492 |bibcode=2008FrEE....6..485M |doi=10.1890/070064 }}</ref><ref name=":22" />

==== United States ====
In the [[Great Lakes region]] the [[sea lamprey]] is an invasive species. In its original habitat, it had co-evolved as a [[Parasitism |parasite]] that did not kill its host. However, in the Great Lakes Region, it acts as a predator and can consume up to 40 pounds of fish in its 12–18 month feeding period.<ref name=":0">{{cite web |url=http://www.glfc.org/sea-lamprey.php |title=Great Lakes Fishery Commission – Sea Lamprey |website=www.glfc.org |access-date=October 24, 2017 |archive-date=October 25, 2017 |archive-url=https://web.archive.org/web/20171025023343/http://www.glfc.org/sea-lamprey.php |url-status=live}}</ref> Sea lampreys prey on all types of large fish such as [[lake trout]] and [[salmon]]. The sea lampreys' destructive effects on large fish negatively affect the fishing industry and have helped cause the collapse of the population of some species.<ref name=":0"/>

[[Economic cost]]s from invasive species can be separated into direct costs through production loss in agriculture and forestry, and management costs. Estimated damage and control costs of invasive species in the U.S. amount to more than $138&nbsp;billion annually.<ref name="pimental">{{cite journal |last1=Pimentel |first1=D. |last2=R. |first2=Zuniga |last3=Morrison |first3=D |year=2005 |title=Update on the environmental and economic costs associated with alien-invasive species in the United States |journal=[[Ecological Economics]] |volume=52 |issue=3 |pages=273–288 |doi=10.1016/j.ecolecon.2004.10.002 |bibcode=2005EcoEc..52..273P }}</ref> Economic losses can occur through loss of [[recreation]]al and [[tourism]] revenues.<ref name="simb">{{cite journal |last=Simberloff |first=D. |year=2001 |jstor=41717176 |title=Biological invasions – How are they affecting us, and what can we do about them? |journal=[[Western North American Naturalist]] |volume=61 |issue=3 |pages=308–315}}</ref> When economic costs of invasions are calculated as production loss and management costs, they are low because they do not consider environmental damage; if monetary values were assigned to the [[extinction]] of species, loss in biodiversity, and loss of [[ecosystem services]], costs from impacts of invasive species would drastically increase.<ref name="pimental"/> It is often argued that the key to invasive species management is early detection and rapid response.<ref>{{Cite book |url=https://www.doi.gov/sites/doi.gov/files/migrated/invasivespecies/upload/2008-2012-National-Invasive-Species-Management-Plan.pdf |title=2008–2012 National Invasive Species Management Plan. |publisher=National Invasive Species Council, Department of the Interior |year=2008 |location=Washington, DC. |archive-url=https://web.archive.org/web/20150929011911/https://www.doi.gov/sites/doi.gov/files/migrated/invasivespecies/upload/2008-2012-National-Invasive-Species-Management-Plan.pdf |archive-date=29 September 2015 |url-status=live}}</ref> However, early response only helps when the invasive species is not frequently reintroduced into the managed area, and the cost of response is affordable.<ref>{{Cite journal |last1=Holden |first1=Matthew H. |last2=Nyrop |first2=Jan P. |last3=Ellner |first3=Stephen P. |date=June 1, 2016 |title=The economic benefit of time-varying surveillance effort for invasive species management |journal=[[Journal of Applied Ecology]] |volume=53 |issue=3 |pages=712–721 |doi=10.1111/1365-2664.12617 |doi-access=free|bibcode=2016JApEc..53..712H }}</ref>

[[File:Parthenium smothering native flora in Biodiversity Rich Forest.jpg |thumb |''[[Parthenium hysterophorus]]'', [[Achanakmar Tiger Reserve]]]]

[[Weed]]s reduce yield in [[agriculture]]. Many weeds are accidental introductions that accompany imports of commercial seeds and plants. Introduced weeds in pastures compete with native forage plants, threaten young [[cattle]] (e.g., leafy spurge, ''[[Euphorbia virgata]]'') or are unpalatable because of [[Thorns, spines, and prickles |thorns and spines]] (e.g., [[yellow starthistle]]). Forage loss from invasive weeds on pastures amounts to nearly [[US$]]1&nbsp;billion in the U.S.<ref name="pimental"/> A decline in pollinator services and loss of fruit production has been caused by [[Western honeybee |honey bees]] infected by the invasive [[varroa mite]]. Introduced rats (''[[Rattus rattus]]'' and ''[[Rattus norvegicus |R. norvegicus]]'') have become serious pests<ref>{{cite journal |last1=Gougherty |first1=Andrew V. |last2=Davies |first2=T. Jonathan |title=Towards a phylogenetic ecology of plant pests and pathogens |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |date=8 November 2021 |volume=376 |issue=1837 |pages=20200359 |doi=10.1098/rstb.2020.0359 |pmid=34538142 |pmc=8450633 }}</ref> on farms, destroying stored grains.<ref name="pimental"/> The introduction of leaf miner flies ([[Agromyzidae]]), including the American serpentine leaf miner (''[[Liriomyza trifolii]]''), to California has caused losses in California's [[floriculture]] industry, as the larvae of these invasive species feed on ornamental plants.<ref>{{cite web |url=http://entnemdept.ufl.edu/creatures/veg/leaf/a_serpentine_leafminer.htm |title=American serpentine leafminer – Liriomyza trifolii (Burgess) |website=entnemdept.ufl.edu |access-date=November 20, 2019 |archive-date=November 25, 2019 |archive-url=https://web.archive.org/web/20191125043634/http://entnemdept.ufl.edu/Creatures/veg/leaf/a_serpentine_leafminer.htm |url-status=live}}</ref>

Invasive plant pathogens and insect vectors for plant diseases can suppress agricultural yields and harm nursery stock. [[Citrus]] greening is a [[bacterial disease]] vectored by the invasive [[Asian citrus psyllid]]. As a result, citrus is under quarantine and highly regulated in areas where the psyllid has been found.<ref name="r2">{{Cite web |title=Citrus Greening |url=http://www.clemson.edu/public/regulatory/plant_industry/invasive_exotic_programs/Pest%20Alerts/citrus_greening.html |archive-url=https://archive.today/20130616000111/http://www.clemson.edu/public/regulatory/plant_industry/invasive_exotic_programs/Pest%20Alerts/citrus_greening.html |archive-date=16 June 2013 |website=Clemson Public Service Activities - The Department of Plant Industry}}</ref>

Invasive species can impact outdoor recreation, such as fishing, [[hunting]], [[hiking]], [[wildlife viewing]], and water-based activities. They can damage environmental services including [[water quality]], plant and animal diversity, and [[species abundance]], though the extent of this is under-researched.<ref>{{cite journal |last1=Eiswerth |first1=M.E. |year=2005 |title=Input-output modeling, outdoor recreation, and the economic impacts of weeds |journal=[[Weed Science]] |volume=53 |pages=130–137 |doi=10.1614/WS-04-022R |last2=Darden |first2=Tim D. |last3=Johnson |first3=Wayne S. |last4=Agapoff |first4=Jeanmarie |last5=Harris |first5=Thomas R. |s2cid=85608607 }}</ref> Eurasian watermilfoil (''[[Myriophyllum spicatum]]'') in parts of the US, fills lakes with plants, complicating fishing and boating.<ref>{{Cite web |date=1 November 2006 |title=Eurasian Watermilfoil in the Great Lakes Region |url=http://great-lakes.net/envt/flora-fauna/invasive/milfoil.html |archive-url=https://web.archive.org/web/20080725034837/http://great-lakes.net/envt/flora-fauna/invasive/milfoil.html#overview |archive-date=25 July 2008 |website=Great Lakes Information Network}}</ref> The loud call of the introduced [[common coqui]] depresses real estate values in affected neighborhoods of [[Hawaii]].<ref>{{cite book |url=http://www.aphis.usda.gov/wildlife_damage/nwrc/symposia/invasive_symposium/content/Sin157_167_MVIS.pdf |last1=Sin |first1=Hans |last2=Radford |first2=Adam |year=2007 |chapter =Coqui frog research and management efforts in Hawaii |title=Managing Vertebrate Invasive Species: Proceedings of an International Symposium (G. W. Witmer, W. C. Pitt, K. A. Fagerstone, Eds) |publisher=USDA/APHIS/WS, National Wildlife Research Center |location=Fort Collins, Colorado |access-date=June 26, 2013 |archive-date=May 25, 2017 |archive-url=https://web.archive.org/web/20170525103353/http://www.aphis.usda.gov/wildlife_damage/nwrc/symposia/invasive_symposium/content/Sin157_167_MVIS.pdf}}</ref> The large webs of the orb-weaving spider ''[[Zygiella x-notata]]'', invasive in California, disrupts garden work.<ref>{{Cite web |title=Spider Invaders |url=https://www.kqed.org/quest/9595/spider-invaders |access-date=2020-12-13 |website=KQED |date=October 18, 2010 |archive-date=November 5, 2020 |archive-url=https://web.archive.org/web/20201105170805/https://www.kqed.org/quest/9595/spider-invaders |url-status=live}}</ref>

==== Europe ====
The overall economic cost of invasive alien species in Europe between 1960 and 2020 has been estimated at around US$140 billion (including potential costs that may or may not have actually materialised) or US$78 billion (only including observed costs known to have materialised). These estimates are very conservative. Models based on these data suggest a true ''annual'' cost of around US$140 billion in 2020.<ref>{{Cite journal |last1=Haubrock |first1=Phillip J. |last2=Turbelin |first2=Anna J. |last3=Cuthbert |first3=Ross N. |last4=Novoa |first4=Ana |last5=Taylor |first5=Nigel G. |last6=Angulo |first6=Elena |last7=Ballesteros-Mejia |first7=Liliana |last8=Bodey |first8=Thomas W. |last9=Capinha |first9=César |last10=Diagne |first10=Christophe |last11=Essl |first11=Franz |last12=Golivets |first12=Marina |last13=Kirichenko |first13=Natalia |last14=Kourantidou |first14=Melina |last15=Leroy |first15=Boris |last16=Renault |first16=David |last17=Verbrugge |first17=Laura |last18=Courchamp |first18=Franck |display-authors=6  |title=Economic costs of invasive alien species across Europe |year=2021 |journal=[[Neobiota]] |volume=67 |pages=153–190 |hdl=10138/333320 |s2cid=237460752 |hdl-access=free |doi=10.3897/neobiota.67.58196 |doi-access=free }}</ref>

{{visible anchor |Italy |'''[[Italy]]'''}} is one of the most invaded countries in [[Europe]], with an estimate of more than 3,000 alien species. The impacts of invasive alien species on the economy has been wide-ranging, from management costs, to loss of crops, to infrastructure damage. The overall economic cost of invasions to Italy between 1990 and 2020 was estimated at US$819.76 million (EUR€704.78 million). However, only 15 recorded species have more reliably estimated costs, hence the actual cost may be much larger than the aforementioned sum.<ref>{{cite journal |last1=Haubrock |first1=Phillip J. |last2=Cuthbert |first2=Ross N. |last3=Tricarico |first3=Elena |last4=Diagne |first4=Christophe |last5=Courchamp |first5=Franck |last6=Gozlan |first6=Rodolphe E. |title=The recorded economic costs of alien invasive species in Italy |journal=NeoBiota |date=29 July 2021 |volume=67 |pages=247–266 |doi=10.3897/neobiota.67.57747 |s2cid=238819772 |url=https://hal.archives-ouvertes.fr/hal-03410329/file/CostsinItaly.pdf |doi-access=free |hdl=2158/1262519 }}</ref>

{{visible anchor |France |'''[[France]]'''}} has an estimated minimum of 2,750 introduced and invasive alien species. Renault et al. (2021) obtained 1,583 cost records for 98 invasive alien species and found that they caused a conservative total cost between US$1.2 billion and 11.5 billion over the period 1993–2018. This study extrapolated costs for species invading France, but for which costs were reported only in other countries but not in France, which yielded an additional cost ranging from US$151 million to $3.03 billion. Damage costs were nearly eight times higher than management expenditure. Insects, and in particular the Asian tiger mosquito ''[[Aedes albopictus]]'' and the yellow fever mosquito ''[[Aedes aegypti |Ae. aegypti]]'', totalled very high economic costs, followed by non-graminoid terrestrial flowering and aquatic plants (''[[Ambrosia artemisiifolia]]'', ''[[Ludwigia (plant) |Ludwigia]]'' sp. and ''[[Lagarosiphon major]]''). Over 90% of alien species currently recorded in France had no costs reported in the literature, resulting in high biases in taxonomic, regional and activity sector coverages. However, no reports does not mean that there are no negative consequences and thus no costs.<ref>{{cite journal |last1=Renault |first1=David |last2=Manfrini |first2=Eléna |last3=Leroy |first3=Boris |last4=Diagne |first4=Christophe |last5=Ballesteros-Mejia |first5=Liliana |last6=Angulo |first6=Elena |last7=Courchamp |first7=Franck |title=Biological invasions in France: Alarming costs and even more alarming knowledge gaps |journal=NeoBiota |date=29 July 2021 |volume=67 |pages=191–224 |doi=10.3897/neobiota.67.59134 |s2cid=237462170 |doi-access=free }}</ref>