黄土丘陵区不同立地条件下猪毛蒿种内_种间竞争

3(,,712100)(Artemisiascoparia),,(Agropyroncristatum)(Heteropappusaltaicus),(Stipabungeana),:1),,,,;2),,7,,;3),,,,,,;4),,INTRASPECFICANDINTERSPECFICCOMPETITIONOFARTEMISIASCOPARIAUNDERDIFFERENTSITECONDITIONSINTHEHILLYREGIONOFLOESSPLATEAUDUFengLIANGZong-Suo3SHANLunandCHENXiao-Yan(InstituteofSoilandWaterConservation,ChineseAcademyofSciences,MinistryofWaterResource,StateKeyLaboratoryofSoilErosionandDrylandFarmingonLoessPlateau,NorthwestSci-TechUniversityofAgricultureandForestry,Yangling,Shaanxi712100,China)AbstractBackgroundandAimsInhillyLoessregion,Artemisiascopariaisalwaysthedominatorintheearlyabandonedfieldcommunities.ItmaybereplacedbyAgropyroncristatumorHeteropappusaltaicusorSti2pabungeanainnextsuccessionstagewhennodisturbanceoccurs.InordertostudythedirectionofArtemisiascopariacommunitysuccessionunderdifferentstandingconditions,weconductedtransplantexperimentstotesttheintraspecficandinterspecficcompetitionofArtemisiascopariainriverterraceandnorthernmoundlandand,atthesametime,itsmorphologicaltraitswereinvestigated.MethodsIntheexperiments,ninespecies(threecoexistingspecies,fivelaterserespeciesandArtemisiascopariaitself)werechosenandtransplantedastestspecies,butduetothelowsurvivaloftwospecies,onlysevenspecieswereanalyzedtotesttherelativecompetitionabilitytophytometerArtemisiascopariaunderdif2ferentstandingconditions.KeyResultsTheresultsshowthattheindividualstendtobeminiaturized,i.e.,itscommunitiesarecom2posedmainlyofsmall-sizedindividualsandcompetitioncanchangethemorphologicaltraits.Theunitbiomasscompetitionintensityisbetterthantotalcompetitionintensityinexplainingplantsrelativecompetitiveabilitywhenlocalconditionsandplantsizeareconsidered.Underthenorthernmoundlandandthelowestriverter2race,late-successionalandperennialsspecieshavehighercompetitativeabilitythanearly-successionalandan2nualplants,suggestingthatthecompetitionoflate-againstearly-successionalspeciesisoneofthedrivingforcetosuccession.ComparisonofthecompetitionbetweentheseventestspeciesandtheunitbiomassofArtemisiascoparia,thenorthernmoundlandranksthefirst,lowerriverterracethesecondandthelowestterracethe:2005201206:2005211217:(90302005790502007)3AuthorforcorrespondenceE-mail:[e-mail]2006,30(4)601609JournalofPlantEcology(formerlyActaPhytoecologicaSinica)third,suggestingthatintensivecompetitionoccursmoreseverelyinpoorgrowingconditions.Thereissignifi2cantdifferenceintheabilityofcompetitionbetweenthetestspeciesandArtemisiascopariafromthelowestriv2erterracetothenorthernmoundland,suggestingthattheranksofthecompetitionabilitymayvarydependingonstandingconditions.ConclusionsAscompetitionisoneofthedecisivefactorsinconstructingplantcommunity,theshiftorvaria2tionofcompetitionabilitybetweencoexistingspeciesandserespeciesmayresultindifferentcommunitystruc2tureanddynamics,soitchangesthedirectionandpathwayofsuccessionunderdifferentstandingconditions.KeywordsArtemisiascoparia,Interspecificcompetition,Intraspecficcompetition,Allometry(,1998),(Begonetal.,1990);,(Goldberg,1990)()(Hamiluonetal.,1999)(,,,)(Aguiaretal.,2001;Chen,2001;Leuschneretal.,2001;,2002;TielbÊrger&Kadmon,2000;,2000;,1998)(,2000)(Aerts,1999;Martinetal.,2001;Tilman,1988),(Fowler,1986;Negbi&Evenari,1961):,,,,,2(Colonization-competitiontradeoff),,,,,,,,(Successionniche)(Reesetal.,2001),,,,,(,2004)(Artemisiascoparia),,11.1,23002570h,499.4555.2kJcm-2,490.5663.3mm,6860%80%,7.710.6,142175d,157d,1.2,03733.1,103170.3,3,(1091615.3E,36399.5N,10801090m)(1091258.5E,364002.7N,1270m),:89013204560m23m,520m,(Stipabungeana)(Potentillachi2nensis)(Potentillabifurca)(Artemisiaargyi)(Taraxacummongolicum)3510m,3060m,(Artemisiasacrorum)(Artemisiagiraldii)(Poasphondylodes)(Bothriochloaischaemum)(Cleistogeneschinessis)(Agropyroncrista2tum)(Alliumledebourianum)(Heteropappusaltaicus)22600m,(Sonchusoleraceus)(Sonchusarvensis)(Artemisiascoparia)(Salsolacollina)(Setariaviridis)(Argiophyllumarenarium)1360230(1091136.0E,363900.6N,1090m),5804560m2530m,2.5m,,,(Artemisiaannual)231.21.2.1S1.5m,50cm,2002200369,2422,2561821.2.2,,,200220045115,20cm20cm,30cm,1.5m(Testspecies),,(Phytometer),,,9,:;;,20,20910,109200220049108,,,20043,2004S6:K2Cr2O7;;;NaHCO3;NH4OAc+(1)1.31.3.1WeinerThomas(1992),(,2002):y=ax2+bx+c(1)y,x,,,,logH2logB,HB1Table1SummaryofsoilmoistureandnutritionininvestigationandexperimentsitesInvestigationandexperimentsites(%)Soilmoisturecontent020cm2040cm4060cmSoilnutrientsOrganic(gkg-1)TotalN(gkg-1)ActiveN(mgkg-1)ActiveP(mgkg-1)ActiveK(mgkg-1)ThelowestriverterraceinXinzhuangke10.5510.1211.157.860.7720.364.89122.16NorthernmoundlandinQianyaoxian6.047.287.745.420.3916.452.0874.62ThelowestriverterraceinRentaihou14.7615.2015.8311.250.6320.211.6671.01LowerriverterraceinRentaigou9.0610.7911.287.520.5917.081.8768.434:6031.3.23(Aguiaretal.,2001;Grace,1995)RCIBTotal=(B-B)/B(2)RCIHTotal=(H-H)/H(3)RCIPergram=RCI/B(4)RCI(Ralativeconpetitionintensity),RCITotalRCIPergram,BH,BBHH,BOrgin5.0STATISTICA6.0DPS(,1997),X2,Mann-WhitneyU,Kruskal-Wallis,Spearman22.1269.62g175.0cm,0.15g1.0cm,55.07g84.7cm;101.53g112.8cm,0.18g2.0cm,10.5g51.5cm,,(1),,