Integratedecologicalassessmentofbiophysicalwetland

ecologicalmodelling214(2008)411–420availableat:Linkinghydro-ecologicalmodellingwithgeo-informationtechniquesDeminZhoua,b,∗,HuiliGonga,ZhaoliLiubaKeyLabofResource,EnvironmentandGISinBeijing,CapitalNormalUniversity,55WeishanRoad,Beijing100037,PRChinabKeyLabofWetlandEcologyandEnvironment,NortheastInstituteofGeographyandAgro-ecology,ChineseAcademyofSciences,130012,PRChinaarticleinfoArticlehistory:Received22October2007Receivedinrevisedform10March2008Accepted12March2008Publishedonline21April2008Keywords:Hydro-ecologicalmodelRemotesensingGeographicalinformationsystemWetlandFloodplainabstractWetlandhydro-ecologyisakeyresearchfieldforecologists,hydrologistsandwetlandinvestigatorstoquantifytherelationshipbetweenwetlandecologicalpatternsandhydrologicalmechanisms.Existenceandfunctioningofwetlandsiscrucialforadjacentterrestrialandaquaticecosystems.Hydro-ecologicalresearchpromotesbothprotectionandrestorationofhealthynaturalwetlandsbyfurtherunderstandingthebiophysicalcharacteristicsofwetlandhabitats.Thisstudyestablishesawetlandhydro-ecologicalmodelwiththemethodologicalsupportfromgeographicinformationsystem(GIS)andremotesensing(RS).Itconceptualisesacause–effectchaininterfacefromtherealwetlandecosystem.GISandcomputermodellingmethodsareusedtogeneratethehydrologicalindicatorsbasedonaDigitalElevationModel(DEM).Byinterpretingmulti-temporalRSimages,weproducewetlandclassificationinformationandvariouslandscapeindices.Bothhydrologicalandlandscapeindicatorsareusedtointegratethehydro-ecologicalanalysiswithsomemultidisciplinaryanalysismethods.Fortheapplicationofthewetlandhydro-ecologicalmodel,wepresentacasestudyinaninlandfloodplainwetlandwithinthescaleofacatchment.ThestudysiteistheHongheNationalNatureReserve(HNNR),aRamsar-designatedsiteontheSanjiangPlaininNorth-eastChina.Themulti-temporalLandsatTM7imagesandaDEMofthestudyareaatfinerscaleareusedtogeneratethevariousindicatorsofthewetlandbiophysicalhabitats.Fieldmonitoringdataofhydrologyandecologyareusedtocalibratethegenerateddigitalinforma-tion.Ourhydro-ecologicalanalysispresentstwosignificantresultsbycouplingthewetlandlandscapeecologyintohydrologicalunits:(1)theconstitutionsofthewetlandcommuni-ties(anensembleofplantsthatarespeciallyequippedtoliveinsoggyconditions)intheriverineornon-riverinebiophysicalhabitatsareclearlydifferentinHNNR.Thepatchareaandnumbersofwetlandcommunitiesincreasedfromtheforestrycommunities,thebushcommunities,themeadowcommunitiesthroughtothemarshesinagoodmoisturegra-dientwithintheriverinezone,whilethepredominantpatchareaandnumberreplacedbythetransitionalmeadowcommunitiesbeyondtheriverinezone;(2)thefloodwaterplaysakeyroleoncontrollingthedistributionofthewetlandcommunitiesinHNNR.Thepredomi-nantdistributionoftypicalmarshcommunitiesintheyearlysaturatedzoneexchangedintothelargerdistributionofthewetmeadowintheseasonalsaturatedzone,andthenfinally∗Correspondingauthorat:KeyLabofResource,EnvironmentandGISinBeijing,CapitalNormalUniversity,105NorthroadofWestern3rdRing,Beijing100037,PRChina.Tel.:[phone];fax:[phone].E-mailaddresses:[e-mail],[e-mail](D.Zhou).0304-3800/$–seefrontmatter©2008ElsevierB.V.Allrightsreserved.doi:10.1016/j.ecolmodel.2008.03.014412ecologicalmodelling214(2008)411–420replacedbythepredominantdistributionofthewetmeadowintheyearlyunsaturatedzone.Furthermore,aclusteranalysisforquantitativespatialcharacteristicsofwetlanddis-tributionshowsthenumericaldifferencebetweenmarshesandnon-marshesbiophysicalhabitatsinthecoreHNNR.©2008ElsevierB.V.Allrightsreserved.1.Introduction“Wetlandsareareasofmarsh,fen,peatlandorwater,whethernaturalorartificial,permanentortemporary,withwaterthatisstaticorflowing,fresh,brackishorsalt,includingareasofmarinewaterthedepthofwhichatlowtidedoesnotexceed6m”(RamsarConvention,1971).Theexistenceandfunctioningofwetlandsiscrucialforadjacentterres-trialandaquaticecosystems.Theseriousdegradationofthenaturalwetlandinescapablythreatenstheexistenceofournaturalecosystem,whichdefinitelyrestrictsregionalsustain-abledevelopmentandlong-terminterestsofhumanbeings(Leit˜aoandAhern,2002;Liuetal.,2004).Theresearchofhydro-ecologicalmodellingallowstheefficientprotectionofwetlandsbyprovidingscientificassessmentonthebiophysi-calhabitatofvariouswetlandsaswellasprovidingimportanttoolstoprotectorrestorenaturalwetlands(Hattermannetal.,2006).AspinallandPearson(2000)coupledlandscapeecologywithRSandGISmethodstodevelopaseriesofindica-torsforaddressingecologicalandhydrologicalfunctioningwithinhydrologicalcatchments.ThemethodsfromRSimageanalysis,landscapeecologicalanalysis,spatialinterpolationandnumericalprocessmodellingwereintegratedwithinaGISplatformtogenerateandanalysetheseindicators.Hoerschetal.(2002)createdvegetationmapsbyusingremotelysenseddata.Digitalvegetationinformationaswellaslandformandtopography-dependentmicroclimaticcon-ditionsofsmallreliefpatchesarecommonlyinformedandassessedbyusingGISmethodsinhisr