简介:TheeasternandwesternfrontsofplatemovementinTaiwanIslandandTibetanPlateaurespectivelyarethetwomajorsourcesoftectonicforceforthemorphogensisduringQuaternaryinChina'stropics.SevenexamplesofgeomorphologicaleffectsofplatemovementareenumeratedtodiscussthedifferentiationoftectoniclandformsinspaceandtimeduringQuaternary.ThetectonicmovementtendstobemoreactivesincemiddlePleistocene.Somephenomenasuchasthearc-shapemountainsystems,volcanismandcrustaldeformationimplythatthejuncturezoneofeasternandwesterntectonicforcesislocatedatabout110°E.
简介:Landscapeecologyandlandscapepatternanalysisareimportantcomponentsofnational-scaleprogramstoidentifytrendsinlandcoverchangebecause:1)Statisticsonchangesinlandcoverproportionsarenotspatial.AchangematrixderivedfromGISprovidesusefulinformation,butitdoesnotshowthespatialformofchangeinthelandscape.Landscapepatternmetricsrevealspatialpattern.2)Agrowingbodyofliteraturehasshownthatachangeinlandscapepatternmightindicateimportantchangesinecologicalfunctions:forestconnectivityandspeciesmovements,numberandsizeoffarmpatches,effectsonwaterquality.Spatialpatternisimportantinstructuringecologicalcommunitiesandinmaintainingexistenceofcompetitors.Spatialpatternmaybedeterminedbydisturbanceandmayinturn,determinehowdisturbancespropagatethroughthesystem.3)Sometimeslandscapepatternmaynotsignificantlychange,eventhoughlandcoverproportionsdochange.Or,vice-versa,sometimeslandscapepatterncansignificantlychange,eventhoughlandcoverproportionsdon'tsignificantlychange.4)Landscapepatternisaninherentandimportantpartofdescribinglandscapes:basedontheliterature,oneofthemostimportantdescriptivecharacteristicsofalandscapeisitstexture.Theobjectivesofthispaperareto:1)Explaintheimportanceoftheroleoflandscapeecologyandlandscapepatternanalysisinlandcoverchangestudies;2)Reviewtheliteraturethatspecificallyincorporateslandscapeecologyintolandcoverchangestudies;and3)Listthetheoreticalandtechnicalissuesinvolvedandsuggestsolutionsforthem.
简介:TocontrolsoilerosionandrestorethedegradedenvironmentintheLoessPlateau,alargenumberofmeasuresrelatedtosoilandwaterconservationhavebeenemployedthathaveprofoundlyaffectedcatchmentproperties.Thisstudyconstructedthreeindicatorstocharacterizechangestothecatchmentslope,proposedbothamethodforaregressionanalysisofadjacentimagesandasequencemodel,andappliedmultisourceremotelysensedimagesandGISspatialclusteringanalysistechnologiestoextractthematicinformationandcomprehensivelyanalyzethecatchmentchangecharacteristics.Theresultsindicatethatthecatchmentslopepropertieschangedsignificantly.Atcatchmentscale,theaveragevaluesofARC,DVCandARTwere6.43%,25.57%and4.30%,respectively.Thereweresixclusteringtypesofcatchmentslopepropertychanges.Themaximumandminimumoftheaveragesimilaritiesoftheclusteringtypeswere0.992and0.935.Eachslopecontrolmeasureshadadistincteffectoncatchmentslope;thedominatingfactorofeachclusteringtypewasidentifiedas:Type1:D-VC,Type2:D-VCLU,Type3:D-LUVC,Type4:D-TAVC,Type5:D-TACandType6:D-MFC.Type5andType1coveredthelargestareas,respectivelyoccupying37.28%and31.01%.Catchmentslopepropertychangesalsohaddistincttypesthatdependedontheirgeomorphologicalconditions.Thesefindingsprovideausefulbasisfromwhichtofurtherstudycatchmentslopehydrologicalandsoilerosionprocesses.
简介:Cultivationisoneofthemostimportanthumanactivitiesaffectingthegrasslandecosystembesidesgrazing,butitsimpactsonsoiltotalorganiccarbon(C),especiallyontheliableorganicCfractionshavenotbeenfullyunderstoodyet.Inthispaper,theroleofcroppinginsoilorganicCpoolofdifferentfractionswasinvestigatedinameadowstepperegioninInnerMongoliaofChina,andtherelationshipsbetweendifferentCfractionswerealsodiscussed.TheresultsindicatedthattheconcentrationsofdifferentCfractionsatsteppeandcultivatedlandalldecreasedprogressivelywithsoildepth.Aftertheconversionfromsteppetospringwheatfieldfor36years,totalorganiccarbon(TOC)concentrationatthe0to100cmsoildepthhasdecreasedby12.3%to28.2%,andTOCofthesurfacesoilhorizon,especiallythoseof0-30cmdecreasedmoresignificantly(p<0.01).Thedissolvedorganiccarbon(DOC)andmicrobialbiomasscarbon(MBC)atthedepthof0-40cmwerefoundtohavedecreasedby66.7%to77.1%and36.5%to42.4%,respectively.IntheS.baicalensissteppe,theratiosofsoilDOCtoTOCvariedbetween0.52%and0.60%,andthoseinthespringwheatfieldwereonlyintherangeof0.18%-0.20%.Themicrobialquotients(qMBs)inthespringwheatfield,varyingfrom1.11%to1.40%,werealsolowerthanthoseintheS.baicalensissteppe,whichwereintherangeof1.50%-1.63%.ThechangeofDOCwasmuchmoresensitivetocultivationdisturbance.SoilTOC,DOC,andMBCweresignificantlypositivecorrelatedwitheachotherintheS.baicalensissteppe,butinthespringwheatfield,thecorrelativitybetweenDOCandTOCandthatbetweenDOCandMBCdidnotreachthesignificancelevelof0.05.更多还原
简介:Tamarixnabkhaisoneofthemostwidespreadnabkhas,distributinginthearidregionofChina.Basedontheobservationsoutdoorsandthesimulationexperimentsinlaboratories,analysisinthispaperreferstothebiologicalgeomorphologicfeaturesandgrowthprocessofTamarixnabkhasinthemiddleandlowerreachesoftheHotanRiver,Xin-jiang.AndtheresultsindicatethattheecologicaltypeofTamarixinthestudyareaisakindofTugaicsoilhabitatbasedonthedeepsoilofthePopulusDiversifoliaforestsandshrubs.Thistypeofhabitatcanbedividedintothreekindsofsub-habitatswhichdemonstratethefeaturesofecologicalenvironmentofTamarixnabkhasduringthedifferentialdevelopedphases.Meanwhile,theTamarixnabkhacanexertintensifieddisturbancecurrentonwind-sandflowontheground,anditsrootandstemsnotonlyhavestrongpotentialofsproutingbutarecharacteristicofwinderosion-tolerance,resistancetobeburiedbysandandrespectivelytoughrigidofthelignifiedbranches,forithasaratherlongerlife-time.Thus,thewindspeedprofileinfluencedbytheTamarixnabkhaisdifferentfromthePhragmitesnabkhaandAlhaginabkha.Andthestructureofthewindflowisbeneficialtoaeoliansandaccumulatingin/aroundTamarixshrub,whichcancreateuniqueTamarixnabkhaswithhigheraveragegradientandlongerperiodicityoflife.Tamarixnabkhaevolutionintheareaexperiencedthreestages:growthstage,matureandsteadystageandwitheringstage.Ineachstage,morpho-logicalfeaturesandgeomorphicprocessofTamarixnabkhaaredifferentduetothediscrepantinteractionbetweenthenabkhaandaeoliansandflow.
简介:TheLoesspositiveandnegativeterrains(P-Nterrains),whicharewidelydistrib-utedontheLoessPlateau,arediscussedforthefirsttimebyintroducingitscharacteristic,demarcationaswellasextractionmethodfromhigh-resolutionDigitalElevationModels.Us-ing5m-resolutionDEMsasoriginaltestdata,P-Nterrainsof48geomorphologicalunitsindifferentpartsofShaanxiLoessPlateauareextractedaccurately.Thensixindicatorsforde-pictingthegeomorphologiclandscapeandspatialconfigurationcharacteristicofP-Nterrainsareproposed.ThespatialdistributionrulesoftheseindicatorsandtherelationshipbetweentheP-NterrainsandLoessreliefarediscussedforfurtherunderstandingofLoesslandforms.Finally,withtheintegrationofP-Nterrainsandtraditionalterrainindices,aseriesofun-supervisedclassificationmethodsareappliedtomakeaproperlandformclassificationinnorthernShaanxi.ResultsshowthatP-NterrainsareaneffectcluetorevealenergyandsubstancedistributionrulesontheLoessPlateau.AcontinuouschangeofP-NterrainsfromsouthtonorthinShaanxiLoessPlateaushowsanobviousspatialdifferenceofLoessland-formsandthepositiveterrainareaonlyaccountedfor60.5%inthisregion.TheP-Nterrainsparticipantlandformclassificationmethodincreasesvalidityoftheresult,especiallyintheLoesstableland,Loesstableland-ridgeandtheLoesslow-hillarea.ThisresearchissignificantonthestudyofLoesslandformswiththeDigitalTerrainsAnalysismethods.
简介:Thegoalofthisstudyistoprovideinformationontheprocessofpotholegrowthonagorgestreambed.PotholegeometriesweremeasuredinareachoftheDaburiverbedattheheadofagorgemorethan200mdeeplyincisingintoa650-750mhighplanationsurfaceformedinthemiddleMioceneinnorthernGuangdong,China.Geometricandderivativedataofthepotholesobtainedfromfieldworkwereinterpretedusingstandardstatisticalmethodologies.Ourstudyshowsthattheformationanddevelopmentofastreampotholewereonlyrelatedtolocalconditionsofastreamreachwherethepotholeoccurs;theweaknesses,whichareusuallyintersectfractures,typicallyinterconnectedverticaljoints,ortriangularpitsgeneratedbyhittingofrockfragmentsduringfloods,initiatethepotholedevelopmentonastreambed;thegeometricaldimensionsofthepotholesarecontrolledbytectonicjointsdevelopedinbedrockofthestreamreach;theradiusandthedepthofpotholesarestrongly(log)positivecorrelated;thepotholeshapesandtheflowpatternsareinconstantduringpotholegrowth;apotholecanbeformedwithinashortperiod,butcannotbefullydevelopedandmaintainedforalongtimeinastrongincisionstreambed.ThefindinginourstudycanimprovetheunderstandingofQuaternaryenvironmentinGuangdong.
简介:TheGurbantunggutDesertisthelargeststableandsemi-stablesanddesertinChina,yetfewdataexistonvegetationpatternandspecies-environmentrelationshipsforthesediversedesertlandscapes.Thesanddunesofthesurveyareaaremainlyofthelongitudinalformfromnorthtosouth,butcheckerboard-shapedandhoneycomb-shapedformsarealsopresent,withtheheightof10-50m.Wemeasuredvegetationandsoildataonnorth-southtransectsandcomparedthemwithvegetationandsoildataoneast-westtransects.Analysisrevealedthatthevaryingtrendandstrengthofthespeciesdiversity,dominanceandcoveroftheplantcommunitiesinthelongitudinalandtransversedirectionsacrossthelandscapearesignificantlydifferent.TheresultsofCCAordinationshowthatthemicro-habitatsofsoilorganicmatter(OM),soilsalts(TS),sortingindex(σ),topsoilwater-content(SM)andpHrelatetothedifferencesinvegetationobservedasdifferencesinspeciesassemblagefromsalt-intolerantephemerals,micro-subshrubsandsubshrubstosalt-tolerantshrubsandmicro-arbors.Theterrain(alt.)andsoiltexture(thecontentsofMzandφ1)affectthespatialdifferentiationofmanyspecies.However,thisspatialdifferentiationisnotsomarkedontransectsrunninglongitudinallywiththelandscape,inthesamedirectionasthedunes.Thespeciesofthedesertvegetationhaveformedthreeassemblagesundertheactionofhabitatgradients,relatingtothreesectionsrunningtransverselyacrossthelandscape,atrightanglestothedirectionofthedunecrests.Inthemid-eastsectionofthestudyareathetopographyishigher,withsand-landsordune-slopeswithcoarseparticles.HerethedominantvegetationcomprisesshrubsandsubshrubsofSeriphidiumsantoliumandEphedradistachya,withlargenumbersofephemeralandephemeroidplantsofSeneciosubdentatus,andCarexphysodesinspringandsummer.Onthesoilofthedune-slopesinthemidwestofthestudyarea,withcoarseparticlesandabundantTK,theplantassemblageofHaloxylonpersicu
简介:ThesouthcoastalplainofLaizhouBayisoneofthetypicalsalt-waterintrusionareasinChina,theoccurrenceanddevelopmentofwhichwascloselyrelatedwiththepa-laeoenvironmentevolution.Systematicanalysesofpollen,foraminiferaandgrainsizecom-positionbasedon14Candluminescencedatingfromtwosedimentcoreswereperformedforthepurposeofunderstandingthesalt-waterintrusioninthecoastalplainofLaizhouBayfromtheperspectiveofenvironmentalevolutionsincelatePleistocene.Itcouldbeclassifiedintosevenevolutionstagessince120kaBP:120–85kaBPwasatransitionperiodfromcoldtowarm;85–76kaBPwasaperiodwithwarmandwetclimatehavingswamplakesdevelopedinthelowerreachesoftheWeiheRiver,southcoastalplainofLaizhouBay;76–50kaBPwascharacterizedbygrasslandvegetationandcoarsesedimentsinterrestrialenvironment,whichwastheearlystageofDaliIce-Age;50–24kaBPwasaperiodwithalternateseadepositioninthesouthcoastalplainofLaizhouBay;24–10kaBPwasthelatestageofDaliIce-AgewithcoldestperiodofQuaternary,thesouthcoastalplainofLaizhouBaywasdrygrasslandandloessdepositionenvironment;10–4kaBPwasanotherwarmandwetclimateperiod,sealevelwashighandregressedat4kaBP;andhasbeenthemodernsedimentaryenvironmentsince4kaBP.Amongthethreewarmstages,including85–76kaBP,50–24kaBPand10–4kaBP,correspondedtolateYangkou,GuangraoandKenliseawatertransgressionrespec-tively.ThedurationofthelatteroneinsouthcoastalplainofLaizhouBaywaslongerthanthatinwestcoastofBohaiSeaandeastcoastofLaizhouBay.Thethreeperiodsofseawatertransgressionformedthefoundationofsalt-waterintrusioninthisarea.
简介:InthisstudytherelationshipbetweentheArcticOscillation(AO)andclimateinChinainborealwinterareinvestigated.Correlationanalysisforthelast41yearsshowsthatthewintertemperatureandprecipitationinChinachangeinphasewithAO.Highpostiviecorrelation(>0.04)betweentemperatureandAOappearsinthenorthernChina.HighcorrelationcoefficientsbetweenprecipitationandAOcoverthesouthernChina(closetotheSouthChyinaSea)andthecentralChina(between30°-40°Nandeastof-100°E),withthevaluesvaryingbetween+0.3and+0.4.ItisfoundthatduringthepastseveraldecadestheprecipitationwasstronglyaffectedbyAO,butforthetemperaturetheSiberianHighplaysamoreimportantrole.AttheinterdecadaltimescaletheAOhassignificantinfluenceonbothtemperatureandpreciptiation.MultivariateregressionanalysisdemonstratesthatAOandtheSiberianHighrelatedvarianceintemperatureandprecipitationis35%and11%respectively,Forprecipitation,howevertheportionisratherlow,implyingthatsomeotherfactorsmayberesponsibleforthechangesinprecipitation,inadditiontoAOandtheSiberianHigh.
简介:UsingthemethodsofcombininglandscapeecologywithGISspatialanalysis,thispaperanalysesthedynamicsofthemarshlandscapestuctureoftheSanjingPlaininthepast20years,furthermore,takingFujinCounty,locatedinthenorthoftheplain,asanexample,analyzestheconversionbetweenmarshandotherlandusetypes.ItisshownthatthemarshintheSanjiangPlaindecreasedgreatlyinthepast20years,butthetrendhasbeguntoreverse,Themarshareadecreasedby51.33%from1980to1996,whereasitdecreasedby4.19%from1996to2000.Thefragmentationofthemarshincreased;thenumberofthepatchesincreasedby326from1986to1996,whereasitonlyincreasedby18patchesfrom1996to2000,Itisobviousthatthespeedofpatchesnumberdiminishedandthemarshfragmentationdecreased,whichshowsthatthereclamationofthemarshconvertedfromthefragmentationtothebriminalargeareaofthemarsh.Thereclaimedmarshhasmainlyconvertedtopaddyfieldanddryland.Largeareaofthemarsh.Thereclaimedmarshhasmainlyconvertedtopaddyfiedldanddryland.Large-scalereclamationintheSanjiangPlaininfluencesitsnaturalenvironmentdirectly:theclimateoftheregionturnsfromcoldandwettowarmanddry,whichmakesthemarshbothinthelow-temperaturenorthernpartandinthedeeplystagnanteasternpartsuitableforfurtheragriculturaldevelopment.
简介:Accordingtodifferencesinvegetationtypesandtheircoverage,combiningthelatestresearch,usingtheoryandmethodonthevalueofvegetationecosystemservices,thispapernotonlycalculatedgoodsproducedbydifferenttypesofvegetationbutalsoestimatedthevalueofvariousvegetationecosystemservicesandsetupdatabase,GISandeco-accountofvegetationecosystem.Theresultwasasfollows:thevalueofvegetation''sprimaryproductivity,soilandfertilityconservation,waterconservation.CO2fixationandO2releasewas199.6billionyuan/a22.64billionyuan/a22.6billionyuan/a,352.24billionyuan/aand374.19billionyuan/a,respectively.Thetotalvalueofecosystemserviceswas968.33billionyuan/a.Thetemperatedeciduousbroad-leavedforesthadthehighestcontributionrate,accountingfor16.42%,Theresultofvaluecanreflectregionalrealitymoreexactly.
简介:Theprobailityofcranelivinginreedywetlandscanreach100%,atthesametime,theareaofreed,thewaterlevelandadjacentwaterareaaremainfactorswhichcontrolthecrane''''''''shabitatselection.Weallknowthatallthesefactorsarespatiallyheterogeneous.FortheXianghaiwetlandsafetyandtoprotecttheXianghaiwetlandhabitatofcrane,thispaperhasmainlyidentifiedasolutiontotheseproblems.ThewetlandinformationisextractedfromtheTMimages,whichreflectthewholewetlandlandscapeandareveryimportantforbothquantitativeanalysisofremotesensingobservationoftheearthsystemandpositioninganalysisinGISdatabasethatisautomaticallyextractedfromDEM.TheDEMforXianghaicharacteristicsoftopographyiscreated.OnthebasisoftheGRIDSUBMODULE,applyingtheGISspatialoverlayanalysis,therelationshipbetweenthewaterlevelandthereedareabelowthewaterlevelandtheratingdistributionmapsofreedareaabovewaterlevelisestablished,Whenthewaterlevelreachesthealtitudeof165n,thereedarea,981.2haismaximum,i.e.,thewaterlevelof165mistheoptimal.
简介:Diversityindicesandabundancedistributionmodelsarestatisticaltoolswhichecologistshaveappliedfordecadesforanalyzingtheintrinsicregularitiesofvariousecologicalentities,Inthiswork,wehaveappliedthesetechniquestousethenotionssuchaspedodiversity(asanexampleofgeodiversityinabroadsense),inordertodectectthedifferencesandsimilaritiesbetweenbothnaturalresources,biologicalandnon-biological,ThediscussionhasmainlybeenconductedthroughthestudyoflandformbasedpedodiversityanalysisappliedtoSOTERdigitaldatabasesinHanianIslan,China,ThemainanalyticalmethodsincludeindicesofrichnesSthatarethenumberofthecategories(SOTERunitsrelatingtodifferentsoilsinthiswork),indicesbasedonproportionalabundanceofcategoriesHandEwhicharenotonlythenumberbutalsotheirrelativeabundance(inourcase,therelativeareaoccupiedbyeachpedotaxa)istakenintoaccount,modelsofthedistributionofabundaceofcategoriesthatprovidethemostcompletedescriptionbutalsotheleastabridgedandGISmappingtoshowthespatialvariationdigitally.
简介:土地利用变化包括土地利用结构和土地利用强度两个方面,是土地利用类型从低生态位层次向高生态位转变的自组织行为。对不同层次的土地利用生态位进行控制与协调,才能实现一定耕地保有量下土地利用资源场的均衡。而这种均衡正是耕地总量动态平衡得以实现的前提。在生态位势理论与系统边界理论的基础上,论文构建了土地利用经济生态位的模型,并以江苏省锡山市为例定量分析了不同土地利用类型相互作用的强度。研究显示,经济发达区非农用地与农用地生态位差较大,城市化进程加快,使耕地更易损失。从资源流动的场论分析角度。探讨了建立耕地保护机制的途径和方法。在目前的水平上,把土地利用生态位作为土地利用/覆被研究中的一种新方法论更有意义。
简介:城市边缘区是城市中最活跃、变化最为迅速的地区,是城市研究的重点地区之一。在分行了城市边缘区土地利用结构持征以及土地利用结构的形成机制的基础上,设计了城市边缘区土地利用动态规划管理系统,包括动态监测于系统、预警子系统和决策于系统三部分。系统的建立围绕边缘区土地的增值特点向土地利用动态更替规律,通过对边缘区土地质迢和地价的动态评价,模拟边缘区土地利用的动态更替趋势,在此基础上,从生态环境效益、社会效益和经济效益三方面对边缘区已有的土地利用规划进行分行和调整,并据此提出管理措施。作为一个循环反馈的运行机制,系统充分利用经济杠杆作为调节的终结,以保证规划的合理调整和实施可能,从而促进边缘区土地利用结构的优化。
简介:随着社会经济的发展,我国的土地整理必然从增加耕地面积的单目标向提高农业综合生产能力、改善和保护生态环境、促进乡村基础设施建设的多目标方向发展。因此,科学分析土地整理潜力是目前边切需要解决的问题,也是科学编制土地整理专项规划及进行土地整理项目规划设计的需要。从内涵上讲,土地整理潜力是相对于一定土地整理标准而言的潜力,是经济、生态条件约束下的潜力,其实质是土地利用潜力。从来源上分析,耕地整理潜力主要来源于农村道路、排酒沟渠的整治与完善、田块的合并与规整、限制因素的改造与消除、农田防护林网的修建与完善。农村居民点整理潜力主要来源于居民宅基地用地量的降低、建筑容积率的提高、闲散土地的再利用、自然村向中心村的合并以及村内基础设施与公共设施的配套完善。