Comparison And Analysis Of Leaf Functional Traits Among Main Forest Communities And Dominant Species In Mt. Dongling Of Beijing

Plant functional trait has been a hot topic in ecological research in recent years.Of which leaf functional trait is most closely related with biomass,resource acquisition and utilization,and resource use efficiency of plants.In this thesis,leaf dry matter content(LDMC),leaf size,specific leaf area(SLA),leaf thickness,leaf nitrogen content (LNC),leaf phosphorus content(LPC)and leaf kalium content(LKC)were chosen,and researches were done in the main broad-leaved forest communities in Mr.Dongling of Beijing.Aim at exploring the characters of relationships among different leaf functional traits in forest communities,topographic factors impacts on leaf functional traits and influences of elevation and leaf direction on leaf functional traits.Leaf functional traits of frequent broad-leaved forest communities were compared on community level.Issues were explored about functional traits that reflect the differences between communities best,and whether leaf functional traits relate to dominant plant classification of zonal vegetation was also studied.The main results are as follows:1,LDMC was negatively correlated with SLA,LNC,LPC and LKC;Leaf size was positively correlated with leaf thickness;SLA had positive correlation with LNC,LPC and LKC;LNC had positive correlation with LPC and LKC;LPC was positively correlated with LKC.2,Elevation was the most influential topographic factor for leaf size,LNC and LKC; LDMC and leaf thickness was most affected by steepness of slope;and slope position affected SLA and LPC most.3,Leaf functional traits of dominant trees variated with elevation regularly,reflecting the influence of elevation on leaf functional traits.LDMC and LNC increased with altitude, while SLA decreased.LPC had no significant variation with altitude.Locating direction of leaves have strong influence on LPC,SLA,LDMC,leaf thickness,LNC and LKC,but weak influence on leaf size.4,LDMC of herb species were generally lower than trees and shrubs,while SLA,LPC and LKC were higher;leaf size and leaf thickness showed no obvious rules among life forms;LNC of three life forms showed tiny differences.LDMC and SLA of shrubs and herbs variated among communities similarly,so did LKC of trees and shrubs.LNC and LPC of three life forms variated among communities similarly.N:P variations of three life forms were quantitatively close and had a same variating trend.5,According to the SLA and LDMC of tree layer,the five communities can be classified into three groups:the first group consists of Betula dahurica forest and Populus davidiana forest,the second group contains mainly Quercus liaotungensis forest,and the third group consists of Juglans mandshurica forest and Tilia mandshurica forest.The community classification is consistent with the classification by dominant plants of the zonal vegetation,LDMC and SLA are the leaf functional traits that reflect the differences between communities best.6,Betula dahurica forest and Populus davidiana forest showed high LDMC and low SLA,and their N:P was very low,indicated the character of pioneer species.Very high LDMC and very low SLA was a character of Quercus liaotungensis forest,which was suitable for dry habitats.At the same time,N:P of Quercus liaotungensis forest was very high,showing a trait of dominant species in later succession stage.Juglans mandshurica forest and Tilia mandshurica forest indicated low LDMC and high SLA,which accommodated to humid habitats.