短花針茅荒漠草原土壤種子庫對不同放牧強度的響應(yīng).pdf

1、內(nèi)蒙古農(nóng)業(yè)大學(xué)碩士學(xué)位論文短花針茅荒漠草原土壤種子庫對不同放牧強度的響應(yīng)姓名：李志強申請學(xué)位級別：碩士專業(yè)：生態(tài)學(xué)指導(dǎo)教師：王明玖20090501ResponseofsoilseedbanktodifferentgrfizingintensitiesintheStipabrevifloradesertSteppeAbstractInInnerMongoliaStipabrevifloradesertsteppe，theuseofrand

2、omfieldsamplingandlaboratorygerminationoffixed—pointmethodofcombiningforthe8yearsunderdifferentgrazingintensitiesofthefencethegrasssoilseedbankdoaresearchin2007to2008Discussionofdifferentgrazingintensityunderthedesertgra

3、sslandsoilseedbankandformationmechanismofthechangeinmechanismfortherestorationofdesertgrasslandvegetationandprovideatheoreticalbasisTheresultsareasfollows：1Thetotaldensitydecreasedwiththegrazingintensityincreasing2Thelay

4、erwhichsoilseedbankofalltheexperimentalplotsmainlydistributedinwas0“20cm，percentageoftotaldensitywas81％“97％ThedensityofsoilseedbankdecreasedgraduallyinO～lOcm、10～20cmand20～30cmsoillayerwiththegrazingintensityincreasing3De

5、nsityofPerennialdecreasealongwithgrazingintensityincreasinginvariouspilotareasThechangeofannualandbiennialplantsisbigwiththeseason，mainlyintheJuneandOctoberTheratioincreasedinhighgrazingplotsSmallsemishrubsdidnotchangewh

6、iletheperennialplantisthemainspeciesinthepersistentseedbankinthepilotarea4Speciesdiversity，richness，evennesswithincreasinggrazingintensitydecreased，butchangeswiththeseasonsisnotacertainregularity5Suggestingthatthespecies

7、compositionoftheseedbankwaslessvariableascomparedwithgrazingSpeciessimilaritynumberbetweenthestandingveget對ionandsoilseedbankdecreasedwiththegrazingintensityincreasing6Experimentalplotsofthegroundvegetationdensityandsoil

8、seedbankdensitywaspositivelycorrelatedKeyword：sambreviflora：Thesoilseedbank：Seasonaldynamics；Spatialstructure；Speciesdiversity；GrazingintensityDirectedby：ProfWANGMingjiu(PhD)AppIicantformasterdegree：LIZhiqiang(Grasslande