青藏高原草地地下生物量与环境因子的关系_杨秀静

第33卷第7期2013年4月

DOI：10．5846/stxb201112281997

生态学报ACTAECOLOGICASINICA

Vol．33，No．7Apr．，2013

2013，33（7）：2032-2042．杨秀静，黄玫，王军邦，刘洪升．青藏高原草地地下生物量与环境因子的关系．生态学报，

YangXJ，HuangM，WangJB，LiuHS．BelowgroundbiomassinTibetangrasslandsanditsenvironmentalcontrolfactors．ActaEcologicaSinica，2013，33（7）：2032-2042．

青藏高原草地地下生物量与环境因子的关系

杨秀静，黄

*

玫，王军邦，刘洪升

（生态系统网络观测与模拟重点实验室，中国科学院地理科学与资源研究所，北京100101）

摘要：青藏高原草地生物量大部分分布于地下，地下生物量在其碳循环研究中起着重要的作用。基于大规模野外样地调查数据，分析比较了青藏高原南北和东西样带上草地地下生物量与环境因子的相关关系，探讨了环境因子对地下生物量控制作用的区域差异。研究结果表明：对于所有采样点而言，青藏高原草地地下生物量的环境控制因素主要有土壤含水量、表层土壤有机碳和全氮含量。通过比较南北和东西样带研究结果发现，草地地下生物量与土壤含水量、土壤表层有机碳和全氮含量相关的显在东西样带上明显高于南北样带。同时，东西样带上草地地下生物量与降水量有显著正相关关系，这种关系在南北著性水平，

样带上不显著，表明水分对东西样带草地地下生物量的控制作用较强。气温与南北样带草地地下生物量呈显著负相关，但与东西样带草地地下生物量相关不显著，由此说明环境因子对青藏高原草地地下生物量的控制存在显著区域差异。关键词：青藏高原；地下生物量；样带；高寒草甸；高寒草原

BelowgroundbiomassinTibetangrasslandsanditsenvironmentalcontrolfactors

YANGXiujing，HUANGMei*，WANGJunbang，LIUHongsheng

KeyLaboratoryofEcosystemNetworkObservationandModeling，InstituteofGeographicSciencesandNaturalResourcesResearch，ChineseAcademyofSciences，Beijing100101，China

Abstract：Belowgroundbiomass（BGB），contributing80%oftotalbiomasstograsslandinTibetanPlateau，playsanimportantroleforgrasslandcarboncycling．UnderstandingtherelationshipsbetweenBGBanditsenvironmentfactorsiscrucialforgrasslandresourcesmanagementandpredictingthefutureinfluenceofclimatechangeonTibetangrasslandecosystem．ManypreviousstudieshaveinvestigatedtherelationshipbetweenBGBanditsenvironmentinTibetangrassland，howeverlargeuncertaintiesstillexist，andsomeresearchresultsareevencontroversialduetolimitedgroundsamplings．Thisstudyovercomestheprevioussamplingproblem，analyzestherelationshipbetweenbelowgroundbiomassanditsenvironmentalfactorsbasedonalargescaleoffieldsurveyconductedinAugust2010．

SouthtransectfromtheTotal32fieldsamplingplotswereselectedalongtwotransectsinTibetanplateau：theNorth-Huangyuancounty（36．4°N，100．96°E），Qinghaiprovince，across7latitudessouthwardtoBomicounty（29．64°N，96.72°E），TibetAutonomousRegion，andtheEast-WesttransectmainlylocatedinXigazearea，TibetAutonomousRegion，alongtheYajiangValley，startingfromSagacounty（29．33°N，85．38°E）across7longitudeseastwardtoGongbujiadacounty（29．69°N，92．27°E）．StatisticalmethodswereusedtoanalyzetherelationshipsbetweentheobservedBGBofgrasslandinTibetanPlateauandtheenvironmentalfactorsincludingobservedsoilmoisture，annualprecipitation，annualmeantemperature，soilorganiccarbonandsoilnitrogencontents．

ResearchresultsshowthatsoilmoistureisthemostcriticalcontrollingfactorwhichinfluencesthespatialdistributionofgrasslandBGBinTibetanPlateau．ItispositivelycorrelatedwithTibetangrasslandBGB，explaining52．76%oftotal

2010CB833503）基金项目：国家自然科学基金（40975045）；国家973计划（2010CB950603，收稿日期：2011-12-28；

修订日期：2013-02-20

*通讯作者Correspondingauthor．E-mail：huangm@igsnrr．ac．cn

variationinTibetangrasslandBGB．Forthesetwotransects，thegrasslandBGBismoresignificantlycorrelatedwithsoilmoistureintheEast-Westtransect（R2=0．6744，P＜0．01）thanintheNorth-Southtransect（R2=0．4081，P＜0．01）．

TheconnectionbetweengrasslandBGBandprecipitationiscomplex．ForallTibetangrasslandplots，only7．95%（P＜0．01）ofthevarianceinBGBcanbeexplainedbyprecipitation．GrasslandBGBincreaseswithincreasingprecipitation（R2=0．1910，P＜0．01）intheEast-Westtransect，butthecorrelationbetweenthetwovariablesisinsignificantintheNorth-Southtransect．Suchdiscrepancybetweenthetwotransectsispartiallyduetofluctuanttopographyinthisregion，causinglargedifferencesofevaporationandrunoffoveralargearea，andthussignificantdifferencesingrasslandBGB．

TherelationshipbetweengrasslandBGBandtemperatureisweakwithnosignificantcorrelationbetweentemperatureandgrasslandBGBintheEast-Westtransect．AlongtheNorth-Southtransect，thetemperatureisnegativelycorrelatedwithgrasslandBGB，andexplainsonly11．86%（P=0．0397）ofthevariationingrasslandBGB．

TibetangrasslandBGBispositivelycorrelatedwithsurfacesoilorganiccarbon（R2=0．3094，P＜0．01）andtotalnitrogencontent（R2=0．2081，P＜0．01）．Thepositiverelationshipmaybeexplainedbythefactthatincreasedbelow-groundbiomassisrelatedtoincreasedamountofrootlitterinthesoil，thusincreasedorganiccarbonandtotalnitrogencontentinthesoil．ComparisonoftherelationshipsbetweengrasslandBGBandthesoilorganiccarboninthetwotransectsWesttransectareindicatesthatthecorrelationcoefficient（R2=0．6751）andtheconfidencelevel（P＜0．01）intheEast-higherandmoresignificantthanthose（R2=0．1445，P=0．0222）intheNorth-Southtransect．ThegrasslandBGBisalsocloselyrelatedtosoiltotalNitrogenwitht …… 此处隐藏：16184字，全部文档内容请下载后查看。喜欢就下载吧 ……