北京大学环境问题外籍专家讲座PPT――新草场生态学

TheNewRangelandEcology:ABudthatBlossomedtoaFlower新草场生态学：学科发芽的过程,LynnHuntsingerUniversityofCalifornia,Berkeley,MainPoints要点,Understandingofthedynamicsofrangelandecosystemshavechanged.对草场生态的多变性有新的认识ThemodelsusedintheUnitedStateshavebeenshapedbysocialandeconomicconditionsuniquetoU.S.history.美国的草场管理模型纳入社会和经济的变量Understandingrangelandecologicaldynamics,andusingtherightmodel,isessentialforgoodpolicy.了解草场生态系统的多变性以及使用适合的模型决定着政策的成败,Outline汇报内容,Definitions:whatisrangelandecologyandwhymodels?定义：什么是草场生态学？为什么模型？LinearSuccessionModelbasedonsuccessiontheory基于演替的线性演替模式NewRangelandEcology:StatesandTransitionsModelbasedonnon-equilibriumtheory新草场生态学：基于非平衡理论的状态-过渡模型Influencesondevelopmentpolicy对发展政策产生的影响,Rangelands草场,Rangelands:landsthatarenotcultivated,notartificiallyirrigated,nottimberforests.Theyincludegrasslands,deserts,alpineareas,montanemeadows,tundra,woodlands,savanna,shrublands.草场：没有种植，灌溉和用材木的土地，包括草地，沙地，高寒草原，山地草甸，冻原，林地，热带草原，灌丛带About2/3ofthelandsurfaceoftheearth,Centralquestion:Whatistheimpactofmanagementonrangelands?核心问题：管理对草场带来的影响,Grazing：放牧NoGrazing：没有放牧Fire：燃烧Weather：天气Seeding,plowing,etc.：种、耕,Weusuallymanageatthe“plantcommunity”scale平常在植物群落的尺度上进行管理,The“steppe”vegetationtype：高寒草原的植被类型Aneedlegrass(Stipaspp.)grassland：针茅属为主的草地,EcosystemModels:生态系统模型,Showsomeofthemanyinteractionsamongorganismsandenvironment阐述生物与环境之间的一些关系Helpusorganizeinformation整理信息Canhelppredictmanagementoutcomes预测管理结果Shouldhelptoexplainthesystem说明系统Shouldhelpusunderstandhowthingswork,whichinteractionsareimportant了解不同变量之间的关系，提出那些关系相对重要,Whydoscientistscreatemodels?科学家为什么建立模型？Whydomanagerswantmodels?管理者为什么需要模型？,-organizeinformationandquestions：整理信息和问题,-understandhowasystemworks：认识系统的运作,-predictoutcomesofmanagement：预测管理的结果,-testeffectsofvariables：试验变量的影响,Whatcausesvegetationchange?那些因素导致植被的变化？,Models,basedontheoriesofwhatdrivesvegetationchange,arecreatedto“explain”whathappensonrangelands,andhowrangelandswillrespondtomanagement.基于导致植被变化的理论，建立模型来解读草场发生了什么？草场对管理的反馈？Whatexplanatorymodel(s)fitsrangelandsbest?那些解释模型最适合草场？,ModelsforVegetationChangeatManagementandPlantCommunityScales在植物群落与管理尺度上的植被动态模型,SuccessionModel演替模型,Successionisthechangeinanecosystemorcommunityovertime.Thetimescaleisyears.演替指群落或生态系统在时间尺度上的辩护，其时间尺度指年份Theclassicalmodeldescribesplantsuccessionas:古典模型模型解读植被演替：1)linear线性2)reversible可逆的3)predictable能预测的4)bioticallycontrolled靠生物技术可控制的5)withastableendpoint.稳定的状态,Clements:SpaceforTimeStudyintheTallgrassPrairie克莱门茨：高杆草原在空间上的时间分析,10grasslandsneverplowed10个从未种耕的草地,10grasslandsplowed20yearsago10个种耕20年的草场地,10grasslandsplowedlastyear10个去年种耕的草地,10grasslandsPlowed50yearsago10个种耕50年以前的草地,Awayofstudyingvegetationchangeovertime在时间尺度上研究植被变化的方法,(Clements,1916),Assembleinto“successionalsere”归结到生态演替系列,Disturbance:reversestheprogressiontotheendpoint,startstheprocessoveras“secondarysuccession”干扰：逆转演替发展到终点，重新开始次级演替,Neverplowed/plowed50yearsago,Plowed10yearsago,FreshlyPlowed,Plowed20yearsago,Linear,deterministic(Clementian)successionforaspecificclimate具体气候下的线性的、确定性的演替,Succession(plantinteractions,competition),Disturbance(fire,grazing,plowing),Stable,climax,endpointforclimate,Developslikeanorganismtomaturity.,Linearsuccessionmodel线性演替模型,Seralstage1,Seralstage2,Seralstage3,“Equilibrium”4StableEndPoint,“CLIMAX”,“MID-SERAL”,“PIONEER”,TallgrassPrairie(50yearsagoorneverplowed),Taller,perennialgrasses(20yearsago),Earlygrasses(10yearsago),Pioneerspecies(justplowed),Controversialamongscientists,withotherideaspromoted,butnobigchangeuntilthe90s.科学家之间的争议，直到90年代没有变化,But,aperfectfittomanagementneedsatthetime.但，很好地适应与当时的管理需求,FitthesocialandecologicalconditionsoftheUnitedStates：适应与当时的美国社会和生态的条件Mostrangelandsownedandmanagedbythegovernment,neededa“scientific”waytomakedecisions大部分草场都由政府管理拥有和管理，需要“科学性”的决策Firstgovernmentagencytostartmanagingrangelandsestablishedin1911Clementspublishedin1916.第一次草场管理机构建立与1911，而克莱门茨出版与1916年Usescienceasareasonforallocatingresourcesamonglivestockproducers科学作为依据来把资源分配给各畜牧业生产者,AdoptedforManagement管理者的采取,Increasinggrazingpressure(disturbance),“CLIMAX”,“MID-SERAL”,“PIONEER”,TallgrassPrairie,Taller,perennialgrasses,Earlygrasses,Pioneerspecies(justplowed);annuals,weeds,Carryingcapacity,#animalsallowed,Usedfor“RangeCondition”,“CLIMAX”,“MID-SERAL”,“PIONEER”,Increasinggrazingpressure,Measuremanagementoutcomesbymeasuringhowsimilarthespeciescompositionistoclimax.利用与测量管理的影响：测量物种的结构与顶级群落的相似性,“Degraded”,“Pristine”,Excellent,Poor,Good,Fair,Condition,“RangelandCondition”草场情况,Linear-successionbasedmethodofassessingrangelandconditionwasusedwidelyinthewestuntilrecently.基于线性演替模型的方法在西方草场状况研究中常用Climax=“excellentcondition”顶级群落：最好的的状态Earlysuccessionalstage=“poorcondition”初期延期阶段：不好的状态,Managementgoal:Findtherightlevelofgrazingtomaintain“good”orbetterconditionbasedonsuccessiontheory管理目标：基于演替理论，需要合适的放牧程度来保持较好的草场状态,Theclosertoclimax,thebetterthe“condition”离顶级群落越接近，状态越好Conditionmeasuredbyspeciescomposition:“climax”speciesvs.“pioneer”species状态评估采取物种结构：顶级物种与初期物种的比较Establishandregulatefixed“carryingcapacity”:numberofanimals/mufortheyear.建立与规划承载量：每亩草场能养的牲畜数量,Forgovernmentmanagers对于政府的决策者,Awaytocreaterulesforherders,allocateuse：建立规则和资源分配的方法Awaytomeasureaffectsofmanagement测量管理影响的方法Predictedmanagementoutcomes预测管理结构Onlymanagershadthe“scientificcapacity”tomeasurecondition,setstockingrates：只有管理者具有“科学依据”来衡量状况，并制定承载率Helpedconsolidategovernmentauthority帮助统一政府权利,20thCentury:FourassumptionsforrangelanddevelopmentinU.S.20世纪：管理美国草场发展提出四个设想,Professionalexpertsshouldbeincharge,need“scientific”management-localsknownothing,theyarebackward专家领导管理，需要“科学性”的管理而当地人无知、落后Technologyisthewaytosolveproblems技术是解决问题的方法Goalforrangelandsistomaximizelivestockproductionatasustainablecarryingcapacity草场管理的目标是基于可持续承载率，畜牧业生产加大化Comprehensiverationalplanningiskey-localsareself-interestedandshort-sighted综合理性的规划是关键当地人目光短浅、自利,Outcome:Strongergovernmentcontrol,ManagementMethod管理方法,Establishafixednumberofanimalsforafixedarea:carryingcapacity固定区域里限制牲畜数量：承载率Dividerangelandsintoareasusedbyindividualhouseholdsandregulatecarryingcapacitytosustain“rangelandcondition”草场分配到各户来管理承载率，实现可持续的草场状态,ThankstoM.Fernndez-Gimnezforfigure,Changeinlandtenurefromsharedlandtoindividualland,Landshared,Landusedseparately,Clementiansuccession:doesthemodelfitaridrangelands?克莱门茨演替：该模型是否适合用在干旱草场?？,ClementsresearchinTallGrassPrairie高杆草原Predictable,highrainfallGrassescompetetodrivesuccession,Clementiansuccession:doesthemodelfitaridrangelands?克莱门茨演替：该模型是否适合用在干旱草场？,“LinearDeterministicSuccession”,Seralstage1,Seralstage2,Seralstage3,“StableEquilibrium”4,“CLIMAX”,“MID-SERAL”,“PIONEER”,Excellent,Poor,Good,Increasinggrazingpressure,disturbance,Fair,RangeCondition,Awaytopredictresultsofdisturbance/grazing.,“Degraded”,“Pristine”,ProblemI:NotLinear问题：非线性,Seralstage1,Seralstage2,Seralstage3,“StableEquilibrium”4,“CLIMAX”,“MID-SERAL”,“PIONEER”,Reality:Therearemultiplepathways,andmultiplestablestates.现实：多重渠道和多重稳定状态,“RangeCondition”草场状态,Seralstage1,Seralstage2,Seralstage3,“StableEquilibrium”4,“CLIMAX”,“MID-SERAL”,“PIONEER”,Excellent,Poor,Good,Increasinggrazingpressure,disturbance,Fair,RangeCondition,Awaytomeasuremanagementoutcomes.测量管理结构的方法,“Degraded”,“Pristine”,=,ProblemII:“condition”isavaluejudgment,Excellent,Poor,Good,Fair,Reality:Each“state”orpotentialvegetationcommunity,hasvalue.“Lower”stagesmaybemoreproductive,ormorebiodiverse,thanlaterstages.Earlierstagesmaybemoreusefultoherders,andinsomecases,more“natural”.,Theconceptofdegradationishighlysubjective退化的观点的是主观性强,Changeinspecies?:arethere“good”and“bad”species?物种的变化？:是否有“好的”和“不好”的物种Whetheraspeciesisgoodorbaddependsonyourgoalsandpointofview物种的好坏取决于个人的目标和观点Linearsuccessionmodelscreate“falsenormativevalue”线性演替模型提出“错的规范价值”Changeinbareareas?裸地变化Weather,drought,rodents,orgrazing?天气、干旱、啮齿类动物、还是放牧Lossofsoil?土壤的变化Influenceslongtermproductivity影响长期的生产“Natural”orcausedbymanagement?“自然”的还是管理导致的Somearidlandshaveflood/droughtcycles有些干旱去有干旱、洪水的循环,Majordriverofchangeisgrazing放牧是变化的主导,Seralstage1,Seralstage2,Seralstage3,“StableEquilibrium”4,“CLIMAX”,“MID-SERAL”,“PIONEER”,Excellent,Poor,Good,Increasinggrazingpressure,Fair,Reducegrazingto“improve”vegetationstate.减少放牧来提高植被状态,“Degraded”,“Pristine”,ProblemIII:Majordriverofchangeisabioticfactors非生物因素是变化的主导,Increasinggrazingpressure,Reducinggrazingmaynotleadtoareturntoclimaxstate,andheavygrazingmaynotleadto“degradation”.Climate/weatheroverwhelmsimpactsofgrazingonaridrangelands.减少放牧并非能重回顶级状态，而大量的放牧压力不会导致“退化”。在干旱草场，气候、天气的影响比放牧重要,“Degraded”,“Pristine”,EcologicalSite:Soils,slope,aspect,etc.,PlantCommunity,EcologicalSite:Soils,slope,aspect,etc.,PlantCommunity,Nostabilizingfeedbacks,uncoupledsystem,Problemswiththemodel:itisnotagoodfit模型的问题：不匹配,Changecanbesetoffondifferenttrajectoriesbydisturbance,weatherconditions,seedavailability,etc.andthischangemaynotbereversible,andmayleadtoanalternatestablestateofvegetation.干扰、天气、种子的利用性等多种因素使变化进入不同的轨道Abioticfactorsmaybemajordriversofsystemchange.非生物因素也许是系统变化的主因Includesavaluejudgment:theendstate(climax)is“good”,everythingelseisnotsogood.包含价值评估：顶级的终点号，而其它都不好？Non-climaxstateshavetheirownsetofvaluesforbiodiversity,aesthetics,carbon,etc.非顶级状态都有自己的生物多样性、美观、碳汇等价值,Buildingabettermodel.建立更好的的模型,Non-equilibriumtheoryseekstoexplain:非平衡理论解读,Bioticinteractionsmaynotbethemajordriver生物的相互作用并非主要的驱动因素Multiplepossiblestablestates,notjustoneclimax(Clements,etc)有多重的状态，并非只有一个顶级状态Disturbance,suchasgrazingandfire,mayhaveapositiveroleinecosystems干扰、包括放牧、燃烧等对生态系统具有积极作用Managementoutcomesarenotverypredictable管理结果很难预测,Non-EquilibriumDynamics非平衡动态,Therearemanypossible“stable”stagesofvegetationforagivenecologicalsite.在摸个生态系统中有多个植被稳定状态Theprimarydriverofvegetationchangeisabioticfactors.植被变化主因是非生物因素：Notmanageable难以管理Notresponsivetograzing与放牧并非相应的Unpredictable(e.g.rainfall)难以预测Managementmustbeforuncertainty.Afixed“carryingcapacity”cannotbeset.管理必须基于不确定性：很难建立固定的承载率,ManagementModel:StatesandTransitions管理模型：状态-过渡模型,Identifyan“EcologicalSite”:environmentalconditionsdefineasitesoils,climate,sitehistory.识别一个生态系统点：环境特征定义一个点土壤、气候、该点的历史Identifypossiblevegetationstates识别可能的植被状态Identifythetransitionsamongstates识别不同状态之间的过渡Whatcausesaparticulartransition?Whatledtoaparticularstate?那些因素导致过渡？什么导致特定的状态,Statesandtransitionmodelsmustbeforspecific“EcologicalSites”basedonabioticfactors状态-过渡模型必须在特定生态系统点，基于非生物的因素,Soils土壤Climate气候Aspect,topography方向、地貌,StateandTransitionModels状态-过渡模型,“States”:relativelystableecosystemwithintemporalscaleofinterest“状态”：在指定的时间尺度上的相对稳定的系统2.“Transitions”:changesamongstateswithinspatialandtemporalscaleofinterest“过渡”：在指定的时空尺度，不同状态的变化,S1,S2,T1,T2,Westobyetal.1989,1EcologicalSite,3States,State1,State2,S1,S2,Whyarestatesstable?为什么状态是稳定的？BallandCupDiagramforStatesandTransitions,Transitions,Threshold(needtocrossitforastatechange),T1:LongdroughtT2:Humanaction,T1T2,StatesandTransitionModels状态-过渡模型,Basedondata,notassumptions基于数据而不是设想Canincorporatebothequilibriumandnon-equilibriumdynamics可以包含平衡与非平衡动态Canbechangedaswelearnmore随着学习可以变动Statesandtransitionsaresitespecific状态-过渡是基于个体案例地,Vetter2005:ThedebatebetweenEquilibriumvsNon-equilibrium平衡与非平衡之间的争议,Mostaridandsemi-aridrangelandsystemshavebothequilibriumandnon-equilibriumdynamicsdependingonscaleandsite.基于不同的尺度和案例地，干旱半干旱草场系统有平衡与非平衡两者的动态Coefficientofvariationinrainfallgreaterthanapproximately30%=mostlynon-equilibrium,aridlands降雨量的差异系数大于30%=大部分是非平衡、干旱区,Coefficientofvariationinprecipitation降水量的差异系数,(vonWehrdenetal.2012),ImplicationsforDevelopmentPolicy发展政策的含义,OLD:Fourprinciplesofrangelanddevelopment草场管理的四个原则,Professionalexpertsshouldbeincharge,need“scientific”management-localsknownothing,theyarebackward专家领导管理，需要“科学性”的管理而当地人无知、落后Technologyisthewaytosolveproblems技术是解决问题的方法Goalforrangelandsistomaximizelivestockproductionatasustainablecarryingcapacity草场管理的目标是基于可持续承载率，畜牧业生产加大化Comprehensiverationalplanningiskey-localsareself-interestedandshort-sighted综合理性的规划是关键当地人目光短浅、自利,Fourprinciplesfornon-equilibriumsystems非平衡系统的四个原则,Localknowledgeissitespecificandimportant:cultureincorporateslongtermlearningaboutadaptingtounpredictablecon