WetlandsshrinksimulationusingCellularAutomataacase

1878-0296©2010PublishedbyElsevierdoi:10.1016/j.proenv.2010.10.027Availableonlineat(2010)225–233InternationalSocietyforEnvironmentalInformationSciences2010AnnualConference(ISEIS)WetlandsshrinksimulationusingCellularAutomata:acasestudyinSanjiangPlain,ChinaHuanYua,ZhengweiHea*,XinPanbaCollegeofEarthSciences,ChengduUniversityofTechnology,No.1ErxianBridgeEast3rdRoad,Chengdu610059,ChinabNortheastInstituteofGeographyandAgriculturalEcology,ChineseAcademyofScience,No.3195WeishanRoad,Changchun130012,ChinaAbstractWetlandsareextremelyvaluablenaturalresources,thesimulationofwetlandlandscapespatial-temporalevolutioncanrevealthemechanismsandlawsoflandscapesuccession,achievethesustainablelandscapeuseandprovidewetlandconservationandmanagementdecisionsupport.ThesistakestheinlandfreshwaterwetlandsintheSanjiangPlainforexperimentalregion,carriesoutexperimentofwetlandlandscapechangingprocesssimulation,resultsshowthatvisualeffectsofsimulationandpredictionarebothgood,andthetotalaccuracyofpointstopointsarealsoabove84%,whichverifiesthefeasibilityandeffectivenessofwetlandlandscapespatial-temporalevolutionsimulationusingCellularAutomata,andprovidesanewtechnicalideaandmethodforwetlandlandscapechangeandprotectionresearch.©2010PublishedbyElsevierLtd.Keywords:Wetlands;CellularAutomata;Transformationrules;SanjiangPlain;Land-cover;Simulation1.IntroductionTransformationofthesurfaceoftheEarthreceivesmuchattention.Asaprocessinitself,land-coverchangehashugeimpactsonecosystems,biodiversity,andtheglobalclimate[1].Wetlandsaredefinedasareasofmarsh,fen,peatlandorwater,whethernaturalorartificial,permanentortemporary,withwaterthatisstaticorflowing,fresh,brackishorsalt,includingareasofmarinewaterthedepthofwhichatlowtidedoesnotexceedsixmetresbyConventiononWetlandsofInternationalImportanceEspeciallyasWaterfowlHabitat.Wetlandsareintegralpartsoftheglobalecosystemastheycanpreventorreducetheseverityoffloods,feedgroundwater,andprovideuniquehabitatsforfloraandfauna[2].Moreattentionshouldbepaidtothechangeofwetlandcovers.Wetlands’functiondegradesandareadecreasesrapidlycausedbyactivitiesinthewetlandwatershedsandpredominantlybyagriculturalones,i.e.,cropandlivestockproduction[3].Wetland’sinvestigation,managementandprotectionneedthesupportofnewscientifictechniquesurgently.Becausethebasicinformationonwetlandresourcestatusandtrendsiscriticalforevaluatingtheeffectivenessofwetlandmanagementactivities[4],*Correspondingauthor.Tel.:[phone];fax:[phone].E-mailaddress:[e-mail].226HuanYuetal./ProcediaEnvironmentalSciences2(2010)225–233governmentandwetlandexpertshavebeenpayingmoreandmoreattentiontothelossandgainofthewetland.Andthesimulationofwetlandshrinkcanrealizetheestablishmentofchangeprocess,whichprovideascientificreferenceforrecognizingthedetailandtrendofwetlandchange,andmakethemanagementandprotectionofwetlandsmorereasonable.CellularAutomata(CA)wereoriginallyconceivedbyUlamandNeumanninthe1940stoprovideaformalframeworkforinvestigatingthebehaviourofcomplex,self-reproduciblesystems[5].CAconsistofasimulationenvironmentrepresentedbyagriddedspace(raster),inwhichasetoftransitionrulesdeterminetheattributeofeachgivencelltakingintoaccounttheattributesofcellsinitsvicinities[6].OnekeyfeatureofCAisthatcomplexglobalspatialpatternscanbegeneratedbyasetofsimplelocalrules.This‘bottom-up’approachcoincideswithcomplexitytheoriesstatingthatacomplexsystemcomesfromtheinteractionsofsimplesubsystems[7].CAprovidesaneffectivewayofsimulatingandpredictingthespatial-temporalevolutionofcomplexgeographicalphenomena[8][9].Landscapeorlandusedynamics[6][10][11][12],urbanexpansion[13][14][15][16],spatialdynamicsofanimalsandvegetation’population[17][18][19],epidemicpropagation[20],Wildfirepropagation[21][22],allthesestudieshavedemonstratedthecapabilityofCAforsimulatingandpredictingcomplexgeographicalprocesses.Thispaperpresentsacasestudyfromatypicalinlandwetlandsysteminfast-decreasingregion,SanjiangPlaininChina.Theresearchitpresents,examinesthepotentialofusingCAforsimulatingthechangeprocessofwetlandshrink.Thentwoquestion:whetherandhowtheCAcanbeusedtosimulatethewetlandscoverchangeprocessavailablywillbeanswered.2.StudysiteTheSanjiangPlain,locatesinthenortheastregionofChina,isoneofthelargestfreshwaterwetlandinthecountry(Figure1).Sincetheendofthe1950s,large-scaledevelopmentintheSanjiangPlainmarshhasoccurred[23].By2003,about80%ofnaturalwetlandshadbeenreclaimedforagricultureandwetlandlossstillhappenssofar[24].Withapopulationof7.8million,ofwhich53.4%isengagedinfarming,theSanjiangPlainhasbecomeanimportantcommoditygrainandbeansupplierforChina[25].Theregionalclimateistemperatehumidtosubhumidcontinentalmonsoon.Averagetemperaturesrangefrom-18°CinJanuaryto21–22°CinJuly,withafrost-freeperiodof120–140days.Annualprecipitationis500–650mm,with80%occurringinMay–September.Mostoftheriversattheareahaveriparianwetlandssupportingmeadowandmarshvegetation.Sedge(Carexspp.)isthedominantplantswithPhragmitesspp.scatteredacrosssomeportions[26].Fig.1.Locationofthestu