我国东部温带植物群落的季相及其时空变化特征.pdf

2008, 32 (2)336~ 346 J ournal of Pla nt Ecology ( Chinese Version) 陈效逑 韩建伟 (,, 100871) , ,7 1982~ 1996, :1) , ;, - 1 - 1 ;2) ,0.6 d a ,0.7 d a ;, ; , ; - 1 ,0.9 d a ;3) , 1 ! ,4.3d; , 1 ! ,4.4 d; SEASONAL ASPECT STAGES OF PLANT COMMUNITIES AND ITS SPATIALTEM PORAL VARIATION IN TEMPERATE EASTERN CHINA CHENXiaoQiu andHAN Jian ei College of Urban and Environmental Sciences, MOE Laboratoryf or Earth Sufr ace Processes , Peking University, Bejiing 0087 , China Abstract Aims Our objectiveswere to determine the seasonal aspect stages of plant communities at seven sitesinthetemperateareaof easternChina andanalyze spatialtemporalvariationof theonset datesof seasonal aspect stages and its relationto climaticfactors. Methods e developeda simulatingmethodof phenological cumulativefrequency to determine the seasonal aspect stages of plant communities. Basic ideasof themethodwere to establish a mixed data set composed of the occurrencedatesof all phenophases of observed deciduous trees and shrubs for each site and each year, andthen calculate the frequency and cumulative frequency of the occurrence dates of phenophases in every fiveday periodthroughout each year and for each site. e used a logistic curve to simulate the phenological cumulativefrequency and computed the corresponding datesof maximum changing rate of the curvature asthe onset datesof seasonal aspect stages. Imp ortant f indings The annualmeandatesofgreenupand activephotosynthesisonsetswere delayedwithin creased latitude, whereas the annual mean datesof senesce