…arelikegiant sponges.
Theypreventflooding.Duringheavyrains,theycollectandholdwater.Theyalsoprotectcoastalareasfromstormsurgesthatcanwashawayfragilebeachesandcoastal communities.
…actaswatertreatment facilities.
Theyfilterandcleanwater.Runoffchemicalsfromurbanareasandfarms,likethosefoundinfertilizerandmanure,oftenwashintowetlands.Wetlandplants,fungi,andalgaeabsorbtheseharmfulchemicals.Otherpollutantssinktothebottomwheretheyareburiedinsoiland sediment.
…arehomesformany species.
Manyplantandanimalspeciesarecompletelydependentonwetlandsfortheirsurvival.Two-thirdsoffisheatenworldwidedependonwetlandsduringtheir life cycle.
…aresomeofthemostdiverseecosystemson Earth.
WetlandscoveronlyfivepercentoftheUnitedStates,butmorethanone-thirdofthreatenedorendangeredspeciesintheU.S.liveonlyinwetlands.Anadditional20 percentofthreatenedandendangeredspeciesusewetlandsduringtheir lifecycles.
…areimportanttopeople.Nearly400 millionpeoplelivecloseto—anddependon—wetlands.
Peopleusewetlandstogrowcropslikerice.Riceisastapleinthedietformorethanhalftheworld.Wetlandsarealsousedforfun,suchasfishingandboating.AccordingtotheU.S.FishandWildlifeService,Americansspendmorethan$100 billiononwetland-relatedactivitiesevery year.
Asmuchashalftheworld’swetlandshavedisappearedsince1900,despitetheirvaluetopeopleand wildlife.
Development
![](/nationalgeographic/adventurer_may_2020/what_you_need_to_know_and_wetlands_face_many_threats/716960/GettyImages_200176237_001.480_0_1.jpg)
Developmentoftenchangeswetlandsbyremovingvegetationandfillingordrainingwetlands.Thelandisusedtobuildhouses,roads,andshrimp farms.
Invasive Species
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Theintroductionofnon‑nativeplantsandanimalscausescompetitionforresourcesandleadstoimbalances.Ifnativespeciesdieoff,theecosystemgets disrupted.
Agriculture
![](/nationalgeographic/adventurer_may_2020/what_you_need_to_know_and_wetlands_face_many_threats/716963/GettyImages_1171294580.480_0_1.jpg)
Rich,organicwetlandsoilisoftendrainedandconvertedintoagriculturalland.Andrunofffromnearbyfarmlandcanhurt wetlands.
Climate Change
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Theriseinsealevelscausedbyclimatechangemayleadmanycoastalwetlandstobepermanentlyfloodedby seawater.