Engineering4(2018)582–583Contents lists available at ScienceDirectEngineeringEditorial
WatershedEcologyandItsApplications
ZhifengYang
StateKeyLaboratoryofWaterEnvironmentSimulation,SchoolofEnvironment,BeijingNormalUniversity,Beijing100875,ChinaGlobalclimatechangeandintensehumanactivitiesgreatlyalternaturaleco-hydrologicalprocessesinmulti-scalewatersheds,resultinginaseriesofthreatstohumansocietyandecosystemsthatincludetheincreaseofextremeclimaticevents,waterqualitydegradation,anddecreasesinbiodiversityandecosystemstability.Manytheoriesandapproachesoneco-logicalrestorationfordifferenttypesofwaterenvironments(e.g.,rivers,lakes,marshes,andestuaries)havebeenproposedintheexistingresearch.However,hydrologi-calconnections,massandenergytransportsareusuallyconsider-ableamongthedifferenttypesofwaterenvironmentsinawatershed,andrestorationmeasuresforonecomponenttypicallyaffectothercomponentsinthesamewatershed.Inaddition,theinteractionsthatoccuramongsocialactivities,economicactivities,andnaturaleco-hydrologicalprocessesarecomplex.Therefore,itisessentialtoexploresustainablewatershedmanagementfromasystemsperspective.Watershedecologytreatsnaturalhydrologicalunits(i.e.,water-sheds)assystemsandanalyzestheinteractingbioticandabioticcomponentsinawatershed.Byexploringknowledgeonsystemstructuresandinteractionsamongthehumanandnaturalpro-cessesinawatershed,itoffersusefultoolsformanagerstoassesstheeffectsofenvironmentalchangesonecosystemhealthandtocreatestrategiesforecologicalrestorationfromasystemsperspec-tive.Motivatedbythecriticalsigni?canceofwatershedecologyindirectingsustainablemanagement,thisspecialissueofEngineeringwasproposedinordertoestablishaforumforthediscussionofrecentprogressinwatershedecology.Sevenpapersexploringnewtheoriesandapproachesarecollectedinthisspecialissueandcontributetothediscussiononthefollowingtwohottopics:(1)Environmentalchangesandeco-hydrologicalresponse.Environmentaldataareessentialforrevealingenvironmentalchangesandtheireffects.Inthisissue,Legaetal.conductadataanalysisoftheirabundantcollecteddatainordertoassesstheeffectsofenvironmentalchangesontherisksofnaturalhazards(e.g.,rockfallsanddebris?ows)inamountainregion.Theydemonstratethatappropriatepoliciescanbeplanned,basedonenvironmentaldatacollectionandelaboration.Inadditiontodata,modelingapproachesareimportant.Althoughvariousmodelshavebeendevelopedforeco-hydrologicalsimulation,environmentalchangesincreasetheuncertaintyinmodelingprocessesandtherebyincreasethedif?cultyofmodelcalibration.Fanetal.developamultivariaterisk-assessmentframeworktoevaluatetheoccurrenceofextremeeco-hydrologicalevents,andquantifyparameteruncertaintiesviaaMarkovChainMonteCarloalgo-rithm.Theydemonstratethattheobtainedcon?denceintervalscanbrackettheobservationswell,especiallyfor?oodduration.Shivhareetal.usetheSoilandWaterAssessmentTool(SWAT)forhydrologicalmodelingandcomparethecalibrationperfor-mancesofthreecommontechniques.They?ndthatthetechniqueofsequentialuncertainty?ttingrequirestheleastamountofdataandperformsbestintheircase.(2)Ecologicalrestorationandsustainablewatermanage-ment.Arti?cialmeasurescanassistinecologicalrestoration.Inthisissue,Brownetal.reportontheirdesignfora?oatingislandconsistingofbiologicalandphysical–chemicaltreatmentmodulesfortheremovalofphosphorusfromsurfacewaters.Theremovalef?ciencyofthistreatmentsystemisdemonstratedtobesatisfying(i.e.,about40%–50%)intheircasestudy.Inadditiontoarti?cialmeasures,appropriatemanagementstrate-giesareimportantinpursuingsustainability.Asaedaetal.suggesthydrogenperoxideasaquantitativeindicatorofenvi-ronmentalstressesonplants,anddemonstrateitsusefulnessthroughlaboratoryand?eldexperiments.Sincehydrogenperox-ideisrelativelystableandcanbeconvenientlyquanti?ed,thisstudyoffersausefulapproachforvegetationmanagement.Humanactivitiesareespeciallyintenseinurbanareas,andthreatenurbanecosystems.Yinetal.reportontheirnewmethodfortheregulationofenvironmental?ows(e-?ows)inchannelizedurbanrivers,consideringmultipleecologicaldemandsandeconomiccost.Theirmethodoffersanef?cientandeconomicaltoolfordirectingtheconstructionandmanage-mentofe-?owsupplyprojectsinurbanareas.Asthecon?ictbetweenhumanandecosystemwaterdemandsbecomesincreasinglyserious,sustainablewatermanagementiscrucialforbothhumansandecosystems.Wangetal.proposeaneco-friendlyoperationstrategyformulti-reservoirsystemsinorderZ.Yang/Engineering4(2018)582–583583tocoordinatehumanandecosystemwaterdemands.Theydemonstratethatthisstrategyiseffectiveinmaintainingthekeyecologicalfunctionsofriverswhilemediatingthenegativeeffectsofe-?owprovisionsonhumanbene?ts.Thus,withthepublicationofthisspecialissue,wehopetofurtherthediscus-siononnewprogressinwatershedecology,withafocusonassessingenvironmentalchangesandcreatingstrategiesforenvironmentalrestoration.Engineering 2 (2016) xxx–xxxContents lists available at ScienceDirect
Engineering
Editorial流域生态学及其应用杨志峰State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China在气候变化与人类活动的共同作用下,流域水质恶化、生物多样性降低及生态系统稳定性下降等流域生态退化问题日益严重。现有研究已提出了大量理论、方法和技术,用于不同类型流域单元(河流、湖泊、草地、森林等)的生态保护、修复和管理。然而,流域的不同单元之间普遍存在水文联系,有密切的物质、能量和信息交换,针对其中一类流域单元的生态措施往往会对同一流域其他类型单元产生显著影响。从流域系统层面制定生态保护、修复、管理措施对于流域整体的健康和可持续发展具有重要意义。流域生态学以流域为研究范围,探讨流域系统中生物要素与非生物要素的特性及其之间的复杂关系,并通过揭示流域系统与人类活动和环境变化间的相互影响机理,提出面向流域系统整体健康的保护修复措施。鉴于流域生态学的重要科学和实践价值,本期流域生态专题专门讨论流域生态学的最新研究进展。本专题共收录7篇论文,研究内容主要围绕以下两方面热点议题。(1)环境变化及生态水文响应环境数据对于揭示环境变化及其影响非常重要。Lega等采用多种手段收集了大量环境数据,通过数据分析方法揭示了环境变化对山区自然灾害风险(如泥石流、山体滑坡等)的影响,表明环境数据分析对于制定变化环境下的自然灾害防控策略具有重要指导作用。除数据以外,模拟方法同样重要。Fan等建立了一种多指标的评价框架用于评估极端生态水文事件的发生风险,并通过马尔可夫链蒙特卡罗方法定量了参数不确定性,结果表明该方法可有效评价极端生态水文事件风险,尤其在洪水风险分析方面具有良好效果。Shivhare等将水土保持评价工具(soil and water assessment tool,SWAT)用于水文模拟,并对比了3种常用模型校准技术,结果发现序贯不确定性分析(sequential uncertainty fitting,SUFI)技术所需数据量最小并具有最佳的参数校准效果。上述研究为变化环境下的模型不确定性分析及参数校准提供了参考和工具。(2)流域生态修复与水资源管理人工辅助措施常用于生态修复。Brown等设计了一种新的人工浮岛系统用于地表水的磷去除,该系统同时包含生物处理模块及物理-化学处理模块,案例应用结果发现该浮岛系统效果良好,磷去除率达到40%~50%。除人工辅助措施以外,科学的流域管理策略对于可持续发展非常重要。Asaeda等提出以过氧化氢作为定量指标表征植物所承受的环境压力,并通过实验室内及野外实验相结合的方法验证了其有效性,由于过氧化氢在环境中相对稳定并易于测量,该研究为流域植被管理提供了有效工具。城市地区人类活动相对更加剧烈,继而对生态系统健康产生严重威胁。尹心安等建立了一种针对城市河道的生态流量(e-flow)的调控方法,综合考虑多重生态需求及调控经济成本,该研究为城市河流的生态流量管理及工程设计提供了经济有效的新方法。随着人Author name et al. / Engineering 2(2016) xxx–xxx641类与生态的用水矛盾愈加突出,水资源管理策略需协调人与自然的双重需求。Wang等针对流域水库群系统建立了一种兼顾人与自然需求的生态友好型调度策略,该策略能在有效维持河流重要生态功能的同时减小生态流量保障对人类用水效益所产生的负面影响。以上研究为流域生态修复及水资源综合管理提供了新的视角和方法。
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