Developing-an-index-of-wetland-condition-from-ecological-data

Developinganindexofwetlandconditionfromecologicaldata:AnexampleusingHGMfunctionalvariablesfromtheNanticokewatershed,USAAmyDellerJacobsa,*,MaryE.Kentulab,AlanT.HerlihycaDelawareDepartmentofNaturalResourcesandEnvironmentalControl,DivisionofWaterResources,820SilverLakeBlvd.,Suite220,Dover,DE19904,USAbU.S.EnvironmentalProtectionAgency,NationalHealthandEnvironmentalEffectsLaboratory—WesternEcologyDivision,200SW35thStreet,Corvallis,OR97333,USAcDepartmentofFisheriesandWildlife,OregonStateUniversity,Corvallis,OR97331,USA1.IntroductionThereisanincreasingdemandforinformationthatcanbeusedtounderstandtheecologicalqualityofthewetlandresourceinadditiontostatusandtrendsinthequantityofwetlands(i.e.,area)thatismostcommonlyreported(e.g.,Fennessyetal.,2007).Dataontheecologicalconditionofwetlandscanbeusedtoreportontheambientconditionoftheresource,targetrestorationandprotec-tionefforts,evaluatetheeffectsofmitigationandrestorationpractices,supportregulatorydecisions,andtracktheimpactoflandusedecisions(Fennessyetal.,2007;Wardropetal.,2007a,b;Whighametal.,2007).Whighametal.(2007)andWardropetal.(2007a)havedemonstratedtheuseofhydrogeomorphic(HGM)assessmentstoreportontheconditionofwetlandsonthewatershedscalebyevaluatingtheperformanceofvariousecologicalfunctions(hydrology,biogeochemistry,plantcommunity,habitat,andlandscape).Thisapproachusesmultipleindicestoevaluateconditionbyidentifyinghowspecificfunctionsareperforminginrelationtoreferencestandardsiteswhicharedefinedastheleastdisturbedsitesinthewatershed.Additionally,analysisoftheHGMfunctionscorescandeterminespecificwetlandfeaturesthathavebeenimpacted,thusprovidingguidanceforrestoration.Forexample,intheNanticokeRiverwatershed,thehydrologyfunctioninriverinewetlandswasperformingatalowerlevelthaneitherthewildlifehabitatorplantcommunityfunction(Whighametal.,2007).Thehydrologyfunctionwasusuallylowbecauseofalterationstothestreamchannelthatchangedthehydrologyoftheassociatedwetland.ThissuggestedthattoimprovetheconditionofriverinewetlandsintheNanticoke