J.Geogr.Sci.2023,33(4):885-904DOI:https://doi.org/10.1007/s11442-023-2111-0©2023SciencePressSpringer-VerlagGrowingimpactsoflow-floweventsonvegetationdynamicsinhydrologicallyconnectedwetlandsdownstreamYangtzeRiverBasinaftertheoperationoftheThreeGorgesDamWANGDandan1,LIUYing1,*ZHENGLilin2,3,LIDahui41.NanjingInstituteofEnvironmentalSciences,MinistryofEcologyandEnvironment,Nanjing210042,China;2.KeyLaboratoryofGeographicInformationScience(MinistryofEducation),SchoolofGeographicSciences,EastChinaNormalUniversity,Shanghai200241,China;3.KeyLaboratoryofWatershedGeographicSciences,NanjingInstituteofGeographyandLimnology,CAS,Nanjing210008,China;4.SchoolofGeospatialEngineeringandScience,SunYat-SenUniversity,Zhuhai519082,Guangdong,ChinaAbstract:Wetlandvegetationisintimatelyrelatedtofloodplaininundations,whichcanbeseriouslyaffectedbydamoperation.PoyangLakeisthelargestfloodplainwetlandinChinaandnaturallyconnectedwiththeYangtzeRiverandtheThreeGorgesDam(TGD)upstream.TounderstandthepotentialimpactsofTGDonPoyangLakewetlands,wecollectedremotesensingimageryacquiredduringdryseasonfrom1987to2020andextractedvegetationcoveragedataintheGanjiangNorthern-branchDelta(GND)andtheGanjiangSouth-ern-branchDelta(GSD),usingtheObject-orientedArtificialNeuralNetworkRegression.Principalcomponentsanalysis,correlationanalysis,andtherandomforestmodelwereusedtoexploretheinteractionsbetweenvegetationextentinthetwodeltasand33hydrologicalvariablesregardingmagnitude,duration,timing,andvariation.TheimplementationoftheTGDadvancedandextendedthelow-flowperiodsinPoyangLake.VegetationcoverageintheGNDandGSDincreasedattheratesof0.39and0.22km2/year,respectively.Theres-ervoirstorageattheendofSeptemberacceleratedtherunoffrecessionintheGNDandtheGSD,makinglow-floweventsmoreinfluentialforvegetationdynamicsandshorteningtheresponsetimeofvegetationtothewaterregime.Thisstudyprovidesanimportantreferenceforevaluatingtheimpactsofdamengineeringondownstreamwetlands.Keywords:vegetationcoverage;waterlevelfluctuation;ThreeGorgesDam;Po...
