简介:Northernpeatlandsstorealargeamountofcarbonandplayasignificantroleintheglobalcarboncycle.Owingtothepresenceofwaterloggedandanaerobicconditions,peatlandsaretypicallyasourceofmethane(CH4),averypotentgreenhousegas.ThispaperreviewsthekeymechanismsofpeatlandCH4production,consumptionandtransportandthemajorenvironmentalandbioticcontrolsonpeatlandCH4emissions.TheadvantagesanddisadvantagesofmicrometeorologicalandchambermethodsinmeasuringCH4fluxesfromnorthernpeatlandsarealsodiscussed.ThemagnitudeofCH4fluxvariesconsiderablyamongpeatlandtypes(bogsandfens)andmicrotopographiclocations(hummocksandhollows).Someanthropogenicactivitiesincludingforestry,peatharvestingandindustrialemissionofsulphurdioxidecancauseareductioninCH4releasefromnorthernpeatlands.FurtherresearchshouldbeconductedtoinvestigatetheinfluenceofplantgrowthformsonCH4fluxfromnorthernpeatlands,determinethewatertablethresholdatwhichplantproductioninpeatlandsenhancesCH4release,andquantifypeatlandCH4exchangeatplantcommunitylevelwithahighertemporalresolutionusingautomaticchambers.
简介:打区域是巴基斯坦的一个生物多样性中心。植物种类,特别树,在Swat,区域从全球气候暴露于扑灭威胁变化。用HADCM3A2a全球气候变化情形,种类分发的最大的熵(MaxEnt)建模在未来分发预言了一个可观的变化受苦pindrow(Royle前D.Don)Royle。AUC(在曲线下面的区域)0.972和0.983珍视目前是重要的,未来分发分别地种类当模特儿。象最温暖的季度(bio_10)和年度温度范围(bio_7)的吝啬的温度那样的有关生物与气候的变量显著地作出贡献到模型并且因此影响种类的预言的分发和密度,是清楚的。未来模型预言到一年,2080人口密度将显著地减少。种类的最高的密度在Sulatanr和Mankial的区域在山谷的东方、西方的边阶被记录。在种类的密度和分发的变化能有可观的影响,不是仅仅在树种类本身上,但是在联系subflora上也。
简介:Today42%(9000km^2)oftheareaofHesseiscoveredwithforests.Thetotalareaofforestshasslightlyincreasedsinceseveralyears.ButactuallytheforestsadjacenttotheconurbationsofNorthernHesseinthevicinityofKasselinparticularandintheRhein-MainRegionsurroundingFrankfurtareinaverydifficultposition.Thereisbigdemandforlandtobeconvertedintosettlements,infrastructure,etc.,whilethereisincreasingneedfortheprotectiveandrecreationalfunctionsoftheforests.Thereforemaintenanceofexistingforestsandestablishmentofnewforestsareamongstthemostimportantresponsibilitiesoftheforestauthoritiesonregionalanddistrictlevel.
简介:Adoptionofcertifiedandimprovedhigh-yieldingcropvarietiesisimportantavenueforincreasingagriculturalproductivityandimprovingthelivingstandardofthefarmersindevelopingcountries.ThemainobjectiveofthecurrentstudywastoexaminefactorsaffectingadoptionofimprovedricevarietiesbysmallholderfarmersinNorthernSindh,Pakistan.Therandomsamplingtechniquewasusedtocollectdatafrom220smallholderricefarmersthroughthefacetofaceinterview.Datawereanalyzedusingdescriptivestatisticsandprobitregressionmodel.Theempiricalresultsshowedthatyearofeducation(P≤0.093),farmingexperience(P≤0.043),soilquality(P≤0.077),farmmachineryownership(P≤0.000),accesstomarketinformation(P≤0.055)andcontactwithextensionagents(P≤0.006)hadsignificantlypositiveinfluenceonadoptionofimprovedricevariety,whileage(P≤0.053)hadsignificantlynegativeeffect.
简介:Background:Wintermoth(Operophterabrumata)andmottledumbermoth(Erannisdefoliaria)areforestLepidopteraspeciescharacterizedbyperiodichighabundanceina7–11yearcycle.DuringoutbreakyearstheycauseseveredefoliationinmanyforeststandsinEurope.Inordertobetterunderstandthespatio-temporaldynamicsandelucidatepossibleinfluencesofweather,standandsiteconditions,ageneralizedadditivemixedmodelwasdeveloped.TheinvestigateddatabasewasderivedfromgluebandcatchmonitoringstandsofbothspeciesinCentralandNorthGermany.Fromthegluebandsonlyfemalemothindividualsarecountedandahazardcodeiscalculated.Themodelcanbeemployedtopredicttheexceedanceofawarningthresholdofthishazardcodewhichindicatesapotentialseveredefoliationofoakstandsbywintermothandmottledumberinthecomingspring.Results:Thedevelopedmodelaccountsforspecifictemporalstructuredeffectsforthreelargeecoregionsandrandomeffectsatstandlevel.Duringvariableselectionthenegativemodeleffectofpestcontrolandthepositivemodeleffectsofmeandailyminimumtemperatureinadultstageandprecipitationinearlypupalstagewereidentified.Conclusion:Thedevelopedmodelcanbeusedforshort-termpredictionsofpotentialdefoliationriskinCentralandNorthGermany.Thesepredictionsaresensitivetoweatherconditionsandthepopulationdynamics.However,afutureextensionofthedatabasecomprisingfurtheroutbreakyearswouldallowfordeeperinvestigationofthetemporalandregionalpatternsofthecyclicdynamicsandtheircausalinfluencesonabundanceofwintermothandmottledumber.
简介:Background:Thelargepotentialofthesoilorganiccarbon(SOC)pooltosequesterCO2fromtheatmospherecouldgreatlyamelioratetheeffectoffutureclimatechange.However,thequantityofcarbonstoredinterrestrialsoilslargelydependsuponthemagnitudeofSOCmineralization.SOCmineralizationconstitutesanimportantpartofthecarboncycle,andisdrivenbymanybiophysicalvariables,suchastemperatureandmoisture.Methods:Soilsamplesofapineforest,anoakforest,andapineandoakmixedforestwereincubatedfor387daysunderconditionswithsixtemperaturesettings(5°C,10°C,15°C,20°C,25°C,30°C)andthreelevelsofsoilmoisturecontent(SMC,30%,60%,90%).TheinstantaneousrateofmineralizedSOCwasperiodicallyandautomaticallymeasuredusingaLi-CorCO2analyzer.BasedonthemeasuredamountofmineralizedSOC,carbonfractionswereestimatedseparatelyviafirst-orderkineticone-andtwo-compartmentmodels.Results:Duringthe387dayincubationexperiment,accumulativemineralizedcarbonrangedfrom22.89mgcarbon(C)·g-1SOCat30°Cand30%SMCforthemixedforestto109.20mgC·g-1SOCat15°Cand90%SMCfortheoakforest.Mineralizedrecalcitrantcarbonvariedfrom18.48mgC·g-1SOCat30°Cand30%SMCforthemixedforestto104.98mgC·g-1SOCat15°Cand90%SMCfortheoakforest,andcontributedatleast80%tototalmineralizedcarbon.Conclusions:Basedontheresultsofthisexperiment,thesoilorganicmatterofthepurebroadleavedforestismorevulnerabletosoilmicrobialdegradationinnorthernChina;mostoftheamountofthemineralizedSOCderivedfromtherecalcitrantcarbonpool.Labilecarbonfractionconstitutesonaverage0.4%ofSOCacrossthethreeforesttypesandwasrapidlydigestedbysoilmicrobesintheearlyincubationstage.SOCmineralizationmarkedlyincreasedwithsoilmoisturecontent,andcorrelatedparabolicallytotemperaturewiththehighestvalueat15°C.Nosignificantinteractionwasdetectedamongthese
简介:TherestorationofforestlandscapehasdrawnmuchattentionsincethecatastrophicfiretookplaceonthenorthernslopeofGreatXing'anMountainsin1987.Forestcanopydensity,whichhascloserelationtoforestproductivity,wasselectedasakeyfactortofindhowmuchtheforestqualitywaschanged13yearsafterfire,andhowfireseverity,regenerationwayandterrainfactorsinfluencedtherestorationofforestcanopydensity,basedonforestinventorydatainChina,andusingKendallBivariateCorrelationAnalysis,andDistancesCorrelationAnalysis.Theresultsshowedthatfireseveritywhichwasinverselycorrelatedwithforestcanopydensitygradewasaninitialfactoramongallthatselected.Regenerationwaywhichdidnotremarkablyaffectforestcanopydensityrestorationinshortperiod,mayshortenthecycleofforestsuccessionandpromotetheforestproductivityofconophoriuminthefuture,Amongthethreeterrainfactors,theeffectofslopewasthestrongest,thepositiononslopewasthesecondandtheaspectwasthelast.
简介:Remote-sensingdataforprotectedareasinnorthernTogo,obtainedinthreedifferentyears(2007,2000,and1987),wereusedtoassessandmapchangesinlandcoverandlanduseforthisdroughtpronezone.Thenormalizeddifferencevegetationindex(NDVI)wasappliedtotheimagestomapchangesinvegetation.Anunsupervisedclassification,followedbyclassesrecoding,filtering,identifications,areacomputingandpost-classificationprocesswereappliedtothecompositeofthethreeyearsofNDVIimages.Maximumlikelihoodclassificationwasappliedtothe2007image(ETM+2007)usingasupervisedclassificationprocess.Sevenvegetationclassesweredefinedfromtrainingdatasets.Thesevenclassesincludedthefollowingbiomes:riparianforest,dryforest,floodedvegetation,woodedsavanna,fallows,parkland,andwater.Fortheseclasses,theoverallaccuracyandtheoverallkappastatisticfortheclassifiedmapwere72.5%and0.67,respectively.Dataanalysesindicatedagreatchangeinlandresources;especiallybetween1987and2000probablyduetotheimpactofdemocratizationprocesssocial,economic,andpoliticaldisorderfrom1990.Wide-scalelossofvegetationoccurredduringthisperiod.However,areasofvegetationclearingandregrowthweremorevisiblebetween2000and2007.Themainsourceofconfusioninthecontingencymatrixwasduetoheterogeneitywithincertainclasses.Itcouldalsobeduetospectralhomogeneityamongtheclasses.Thisresearchprovidesabaselineforfutureecologicallandscaperesearchandforthenextmanagementprograminthearea.
简介:AfieldexperimentwasconductedatKezuohouqiCounty,InnerMongoliaAutonomousRegionofChina,whichwaslocatedonthesoutheasternedgeoftheHorqinSandyLand,tostudythespatialvariabilityofsoilnutrientsforasmallscale,nutrient-poor,sandysiteinasemi-aridregionofnorthernChina;toinvestigatewhetherornottherewere'islandsoffertility'attheexperimentalsite;andtodeterminethekeynutrientelementsthatsustainedecosystemstability.Resultsobtainedfromgeostatisticalanalysisindicatedthatthespatialdistributionpatternofsoiltotalnitrogen(STN)wasfardifferentfromthoseofsoilorganicmatter(SOM),totalphosphorus(STP),andtotalpotassium(STK).ComparedtoSOM,STP,andSTK,STNhadalowerstructuralheterogeneityratioandalongerrange,whileotherelementswereallsimilar.Inaddition,STNhadanisotropicspatialstructure,whereastheothershadananisotropicspatialstructure.Thespatialstructurepatternsofherbagespecies,cover,andheightalsodiffered,indicatingthatspatialvariabilitywassubjectedtodifferentecologicalfactors.Differencesinthespatialvariabilitypatternsamongsoilnutrientsandvegetationpropertiesshowedthatsoilnutrientsforasmall-scalewerenottheprimarylimitingfactorsthatinfluencedherbagespatialdistributionpatterns.Incorporatingspatialdistributionpatternsoftreespecies,namely,Pinussylvestrisvar.mongolicaLitv.andshrubLespedezabicolorTurcz.inaresearchplotandusingfractaldimension,SOM,STP,andSTKwereshowntocontributetothe'islandsoffertility'phenomenon,howeverSTNwasnot,possiblymeaningthatnitrogenwasakeylimitingelement.Therefore,duringrestorationofsimilarecosystemsmoreattentionshouldbegiventosoilnitrogen.
简介:Background:Forestmanagementdecisionsarebasedonexpectationsoffuturedevelopments.Forsounddecisionsitisessentialtoaccuratelypredicttheexpectedvaluesinfuturedevelopmentsandtoaccountfortheirinherentuncertainty,forexampletheimpactofclimatechangeonforests.Changingclimaticconditionsaffectforestproduaivityandaltertheriskprofileofforestsandforestenterprises.IntensifyingdroughtstressisseenasonemajorriskfactorthreateningforestmanagementinthenorthGermanlowlands.Droughtstressreducestreegrowthandvitalityandmighteventriggermortality.Butsofar,itisnotpossibletoquantifyeffectsofapersistentdryerclimateonforestproductivityatalevelsuitableforforestmanagement.Methods:Weapplyawell-establishedsingle-treeforestgrowthsimulatortoquantifytheeffectofpersistentdryerclimatesonfutureforestproductivity.WeanalysethegrowthofScotspine(PinussylvestrisL.);Europeanbeech{FagussylvoticoL.)andoak{QuercusroburL.andQuercuspetraeo(Matt.)Liebl.)intwoforestregionsinthenorthGermanlowlandsforatimeintervalof60yearsuntil2070.Thegrowthresponseunderthreedifferentclimateprojectionsiscomparedtoabaselinescenario.Results:Theresultsshowcleardifferencesinvolumeincrementtopersistentdryerclimatesbetweentreespecies.Thefindingsexhibitregionaldifferencesandtemporaltrends.WhilemeanannualincrementatbiologicalrotationageofScotspineandoakpredominantlybenefitsfromtheprojectedclimateconditionsuntil2070,beechmightsufferlossesofupto3m3-ha’-yr1dependingonclimatescenarioandregion.However,intheprojectionperiod2051to2070theuncertaintyrangescomprisepositiveaswellasnegativeclimaticeffectsforallspecies.Conclusions:Theprojectedchangesinforestgrowthserveasquantitativecontributionstoprovidedecisionsupportintheevaluationof,forexample,speciesfuturesitesuitabilityandtimbersupplyassessments.Theanalysiso
简介:在modulating植物生产率的土壤pH的潜在的角色根据干燥质量被估计,在0.25m2空铅形式收获了,在北希腊的二块低生产率的高地草地使遭到了到年度因素的氮(N)和磷(P)授精(15gNm−2year−1和10gPm−2year−1)在最小上3年的时期。在这些特别条件下面,一种积极关系将在土壤pH和植物生产率之间存在,进一步,营养素的那N或P化肥应用限制系统,这被假设,将导致一变弱这种积极关系。一种重要积极关系在其它在二个学习区域和一个积极趋势之一在土壤pH和植物生产率之间被证实。而且,植物生产率增加,后面的授精,看起来在土壤pH植物生产率关系上有有害效果。调查结果支持原来的假设并且加强想法种调停差异的土壤pH植物生产率关系是发生在更多的“typical”下面的更强烈的植物种形成的结果更高的pH在的土壤条件与热带区域对比适度。
简介:RicecropgrowthandyieldinthenorthIranareaffectedbycropdurationandphenology.ThepurposeofthisstudywastocalibrateandvalidatetheORYZA2000modelunderpotentialproductionbasedonexperimentaldataforsimulatingandquantifyingthephenologicaldevelopment,cropdurationandyieldpredictionofricecropinfluencedbydifferentseedlingages.InordertocalibrateandvalidatethecropparametersofORYZA2000model,atwo-yearfieldexperimentwasconductedunderpotentialgrowthconditio...
简介:我们检验了本地社区刺激节目在Baneh城市里在三个forested村庄里改进传统的森林管理,西方的伊朗的北Zagros森林里的库尔德斯坦省。Zagros森林盖住607万哈并且支持富人植物和动物差异。在本地社区聚会和经济系统和传统的森林管理的无效的变化在最近的十年在森林新生的稳定性导致了一种批评状况。由于缺乏生产并且可耕地和产生失业和贫穷,人overexploitedZagros森林。在传统的森林管理的外面的干预创造在本地民族和森林管理组织之间的冲突。为了完成持续森林管理,包括的森林资源保存和自然资源的改进,基于社区的生计,基于森林的重要函数实现林地刺激程序(FIP)是合乎需要的。社区,本地生计上的森林的效果,和从森林提取的产品的表的socio-economics的详细信息不过从本地社区的调查被获得问询表,会见和观察。我们在三个村庄里学习了276个家庭并且在定量分析由业主完成了76张问询表。采样被简单随机的采样(SRS)执行。农村社区的需要例如家畜耕作,主要从特征和村庄的环境特征产生。我们识别了驱动力,压力,地位,影响和回答(DPSIR)设计刺激节目,由DPSIR分析和相互作用分析。来自森林的本地社区好处的评估显示了那以便改进森林管理,319美元将被每个家庭在2010作为刺激每年需要阻止砍并且收集的柴,森林降级的主要原因。
简介:Arbuscularmycorrhizafungi(AMF)arevitalintheregenerationofvegetationindisturbedecosystemsduetotheirnumerousecologicaladvantagesandthereforearegoodindicatorsofsoilandecosystemhealthatlarge.Thisstudywasaimedatdetermininghowtheseasonal,vegetationcoverdensity,edaphicandanthropogenicfactorsaffectAMFrootcolonization(RC)andsporedensity(SD)inDesa’adryAfromontaneforest.AMFRCandSDintherhizosphereoffivedominantwoodyspecies,Juniperusprocera,Oleaeuropaea,Maytenusarbutifolia,CarissaspinarumandDodonaeaangustifoliagrowinginDesa’aforestwerestudiedduringtherainyandthedryseasonsinthreepermanentstudyvegetationcoverdensityplots(dense,medium,andpoor).Eachplot(160×40m2)hastwomanagementpractices(fencedandunfencedplots)ofarea.A100gsampleofrhizospheresoilfrommoisturefreecompositesoilwasusedtodeterminesporedensity.Sporedensityrangedfrom50to4467spores/100gsoil,andallspecieswerecolonizedbyAMFwithinarangeof4–95%.Glomuswasthedominantgenusintherhizosphereofallspecies.VegetationcoverdensitystronglyaffectedSDandRC.TheSDwassignificantlyhigher(p<0.05)inthepoorvegetationcoverdensitythanintheothertwoandlowestinthedensecover;rootcolonizationshowedthereversetrend.Managementpracticessignificantly(p<0.05)influencedAMFSDandRC,withthefencedplotsbeingmorefavoured.Seasonssignificantly(p<0.05)affectedRCandSD.MoreRCandSDwereobservedinthewetperiodthanthedryperiod.CorrelatingAMFSDandRCwithsoilphysicalandchemicalpropertiesshowednosignificantdifference(p>0.05)exceptfortotalnitrogen.Disturbance,vegetationcoverdensity,seasonandtotalnitrogenaresignificantfactorsthatcontrolthedynamicsandmanagementinterventionstomaintaintheforesthealthofdryAfromontaneforests.
简介:Background:Aftertheirdeath,Scotspinetreescanremainstandingfordecadesandsometimesupto200years,forminglong-lastingandecologicallyimportantstructuresinborealforestlandscapes.Standingdeadpinesdecayveryslowlyandwithtimedevelopinto‘kelo'trees,whicharecharacterizedbyhardwoodwithsilvery-coloredappearance.Thesekelotreesrepresentanecologicallyimportant,longlastingandvisuallystrikingelementofthestructureofnaturalpine-dominatedforestsinborealFennoscandiathatisnowadaysvirtuallyabsentfrommanagedforestlandscapes.Methods:Weexaminedandmappedtheamount,structuralfeatures,sitecharacteristicsandspatialdistributionofdeadstandingpinetreesoveratenhectareareainanunmanagedborealforestlandscapeintheKalevalaNationalParkinRussianVienaKarelia.Results:Themeanbasalareaofdeadstandingpinetreesintheforestedpartofthelandscapewas1.7m~2?ha~(-1)andtheestimatedvolume12.7m~3?ha~(-1).Fromthetotalnumberofstandingdeadpinetrees65%werekelotrees,withabasalareaof1.1m~2?ha~(-1)andvolumeof8.0m~3?ha~(-1),theremainderconsistingofstandingdeadpinesalongthecontinuumbetweenarecentlydeadtreeandakelotree.Overall,standingdeadpinesweredistributedthroughoutthestudyarea,buttherewasatendencytowardsspatialclusteringupto<100mdistances.Standingdeadpinesweremostcommonlysituatedonflatgroundorinthemidslopeinthelocaltopography.Inaddition,standingdeadpinescontributedtosubstratediversityalsobycommonlyhavingcharredwoodandbrokentops.Basedonthepresenceofdeadpinesnagsindifferentstageoftransitionfromarecentlydeadpinetoakelowithsilverysurface,itseemsevidentthattheprocessofkelorecruitmentwascontinuouslyinactioninthestudiedlandscape.Conclusions:Kelotreesareanomnipresentfeatureinnaturalpine-dominatedforestlandscapeswithimportantcontributiontoforeststructuralandsubstratediversity.Becauseo