ECOLOGECONCEPTSANDAPLUICAZONSCOPEZTOYStudies ofintraspecific competitionprovide evidence for resource limitation
❖ Studies of intraspecific competition provide evidence for resource limitation
ECOLOGECONCEPTSANDAPLUICAZIONSCOMPEZTOIntraspecific Competition Among Herbaceous Plants
➢ Intraspecific Competition Among Herbaceous Plants
S. natans was grown at highand low densities on a gradientAt lowdensitofnitrogen availabilityS.natans grer10to a large sizeDavid Tilman et al 1989sse8Sorghastrum nutans64S.natansremainedsmallat highdensities23009001,500Soil nitrogen (mg N perkg soil)FIGURE 10.3
David Tilman et al 1989 Sorghastrum nutans
The self-thinning rule predicts thatplants will decrease in populationdensity (self-thin)as the totalbiomass of the population increasesPopulations A,B, C.and D allconverge on a state of lowdensity and high total biomass.LargesseorgjouaoHighinitial numbermedium biomassCHigh initialLow initialMediuminitialAnumber,number,number,lowbiomassDlowbiomassLowlowbiomassHighLowLogarithm of numberof individualsm.WestobySelf-Thinningin Plant Population
• Self-Thinning in Plant Population
As plantings of altalfaMedicagosarw arew, ortality thinnedthe stands as surviving plantsfeached larnersiSelf-Thinning rule(K.Yoda 1963):Msariia population atend ot theexperinent consisted of largerM=KN-3/2plants growinp at lower densiry0.5uedsadaueaFinal densir0.01M,arwplantedathigh densiry ininiall0.05Imitaldensity5,0001.00010.000Density (plantsperm)Whiteand Harper(1970),AlfalfaFGURGTO.NSetfrhinninginpolonswfatata,Nleeeago sativahiieaaper1o7o)
Self-Thinning rule(K. Yoda 1963): M = KN-3/2 White and Harper(1970), Alfalfa