第二章种群生态学(英)

Chapter2PopulationsandPopulationStructureOrganismsEnvironments＝Ecology1＋12(populationecology)1＋23（communityecology）1PopulationPopulation：agroupoforganismsofthesamespecieswhichoccupiesagivenareaatthesametime.BasicunitofcommunityAdaptiveunitofspeciesBasicunitofspeciesexistenceSpecies:agroupoforganismswhicharesimilarinmodality,physiologyandecology,andcanmatebetweeneachother.PopulationSizeorboundary:arbitrary(dependingonquestionunderinvestigation).UnitaryormodularorganismRamatPopulationdynamicsisthecoreofpopulationecology4maincharactersofthepopulation:quantitative(density,reproductionrate,agestructure,lifetableandsurvivalcurve)，spatialandgenetic,systematic.2PopulationdynamicsPopulationsize(density)Thenumberofindividuals(unitaryorganisms)orramets(modularorganisms)presentinagivenarea.AbsolutedensityTotalcountmethodSamplingmethod（quadratmethod,mark-recapaturemethod,removalsampling）Relativedensity（zooaccounting,accountingofzootrace,catchperuniteffort）UnitarydensityandramatdensityPopulationsize(density)dependson:NatalityMortalityImmigrationEmigrationLifetable:thefateofagroupofindividualsbornatapproximatelythesametimefrombirthtotheendofthelifecycleAgeDyingindividualsLivingindividualsMortalityrate0-0.554100054.00.5-1145946153.01-21280115.02-31378916.53-41277615.54-53076439.35-64673462.66-74868869.97-869640108.08-9132571231.09-10187439426.010-11156252619.011-129096937.012-1336500.013-14331.000Svrvivorshipcurve(survivalcurves)Survivorshipdatashowedbysurvivorshipcurve.Survivorshipcurve:agraphshowingtheproportionofsurvivorsonalogscalethrougheachphaseageoflife.MortalitycurveGeneralizedsurvivorshipcurvesAgeSurvivorshipABCLargemammalBirdFishAgestructureandsexratioPostreproductivestageReproductivestagePre-reproductivestageGrowingStationaryDecliningPopulationgrowthPopulationsize：natality,mortality,immigration,emigrationRateofnaturalincreaser：practicalincreaserateofthegivenpopulationinnature.r=natality-mortalityIncreaserate＝r+netmigrationrate=natality–mortality+immigrationrate–emigrationrateinnaterateofincrease(内禀增长率,rm)isthetheoreticalmaximumthatmaybereachedinagivenenvironmentifthepopulationisnotresourcelimited.Itisalsonamed:instantaneousrateofincrease(瞬时增长率)，bioticpotential(生物潜能),reproductivepotential(生殖潜能).rm:constant,geneticallydecided.louse:40.6/y，housemouse:5.4/yBreedingpotentialMaximumnatalityEcologicalnatalityMinimummortalityEcologicalmortalityPopulationincreasemodelNoresource-limitedgrowth(density-independentpopulationgrowth）－‘J’shapedgrowthResource-limitedgrowth（density-dependentpopulationincrease－‘S’shapedgrowthNo-overlappinggenerationPopulationgrowthmodel:Nt+1=NtNt=N0tN:populationsizeT:time:finiterateofincrease＝erRelationshipbetweenrandpopulationdynamics(no-overlappinggeneration)valuervaluePopulationsize1r0increase=1r=0constant01r0decline=0r=-Extinct＝erOverlappinggenerationDifferentialequation:rateofchangeofpopulationsizeattimet=N×rdN/dt=rNIntegralNt=N0ertr=log(averagenumberofoffspringperindividual)/generationtime=lnR0/TPopulationgrowthinlimitedresources（Density-dependentgrowth）Premise：A:EnvironmentalcarryingcapacityKNt=K,dN/dt=0B:Thedeclineinrisproportionaltotheincreaseofdensity.S-shapedcurvedN/dt=rNdN/dt=rN(1－N/K)Logisticequation(逻辑斯谛方程)Nt=K1＋ea－rtPopulationsize/densityEnvironmentalresistance=1-N/KKJshapedcurveS-shapedcurve(K:environmentalcarryingcapacity)TimeNt=N0ertNt=K/(1+ea-rt)Curvecanbedividedinto:LatentperiodAcceleratingperiodTransitionperiodDecliningperiodSaturatingperiodSignificanceofLogisticequationdN/dtNMSYK/2SignificanceofLogisticequationSimple,practicalBasicmodelofpopulationgrowth;Helptoascertainmaximumsustainableyield;randKareimportantconceptsincountermeasureofevolutionism.Populationfluctuations,cyclesandchaosQuantitativecharacters:equilibrium,fluctuationSpatialdistributionpatternUniformpattern(s2m)(uniformresource,intraspeciescompetition)Randompattern(s2=m)(uniformresource,nointraspeciescompetition)Clumpedpattern(s2m)m=(i)/N;s2=[(i–m)2]/(N–1)