浑善达克沙地沙地榆种群年龄结构研究

Study on the Age Structure of Ulmus pumila L.var.Sabulosa Population in Hunshandake Sand Land

基于6个样带的实测数据研究浑善达克沙地处于不同立地类型的沙地榆种群的年龄结构,绘制了沙地榆种群的年龄结构图,结果表明：6种立地类型沙地榆种群年龄结构图均呈壶形,基部、顶部较窄而中部较宽,均为典型衰退型的种群;沙地榆均为处于X1、X9、X10这3个年龄级最少,这3个年龄级沙地榆株数百分比之和在0～5%,几乎出现断代现象;X3、X4这2个年龄级最多,沙地榆株数百分比之和在61%～86%。经不平衡方差分析显示,虽然立地类型不同,6种立地类型的面积不同,沙地榆分布的株数不同,但沙地榆种群的个体年龄级却比较相近,不存在显著性差异,几乎都处于幼树与成年树阶段,缺乏幼苗,更新不良。

Based on the measured data of 6 transects,the age structure of Ulmus pumila L.var.sabulosa population in different site types was studied and the age structure graph of U.pumila L.var.sabulosa population was made.The results showed that with the wider middle part and the relatively narrow top and bottom part,the age structure graphs of U.pumila L.var.sabulosa population in 6 site types showed kettle shape.All the 6 site types belong to the typical declining type.U.pumila L.var.sabulosa belong to the ages of X1、X9、X10 were the least,which totally account for 0～5% of the total number of all U.pumila L.var.sabulosas,almost showed dating tendency;U.pumila L.var.sabulosas belong to the ages of X3、X4 have the most number with their percentage from 61% to 86%.Variance analysis showed that though the area and number of U.pumila L.var.sabulosas of 6 site types were different,the age structure of the individual U.pumila L.var.sabulosa of elm population close to each other and showed no significantly different（P〉0.05）.Almost all U.pumila L.var.sabulosas in U.pumila L.var.sabulosa population were in young or mature stage with the shortage of seedlings and adverse renewal.