乌尔旗汉兴安落叶松群落结构及物种多样性分析

采用方差（v）/均值（m）方法研究乌尔旗汉分布的兴安落叶松群落种群分布格局,采用物种丰富度、多样性指数、均匀度指数分析其物种多样性.结果表明：乌尔旗汉分布的兴安落叶松样地Ⅰ以兴安落叶松为主,有少量白桦和山杨,样地Ⅱ和样地Ⅲ以兴安落叶松为主,有少量白桦;林分密度差异较大：样地Ⅰ（1 740株/hm2）＞样地Ⅲ（1 080株/hm2）＞样地Ⅱ（910株/hm2）.样地Ⅰ和样地Ⅲ的兴安落叶松种群格局表现为聚集分布,样地Ⅱ表现为随机分布.样地物种数为：样地Ⅰ （23种）＞样地Ⅲ（21种）＞样地Ⅱ（19种）,物种丰富度指数和物种多样性指数在垂直结构上均为：草本层＞灌木层＞乔木层;均匀度指数除样地Ⅰ与样地Ⅲ的pielou指数（JsW）和样地Ⅲ的Alatalo指数（Ea）为灌木层＞草本层＞乔木层外,其余均为草本层＞灌木层＞乔木层.

Research on Structure and Species Diversity of Larix gmelinii Community in Orqohan

The species distribution pattern of Larix gmelinii in Orqohan County was analyzed by means of variance （v） / mean （m） method,and the species diversity was studied by species richness,diversity index and evenness index.The results showed that sample plotⅠwas mainly composed of Larix gmelinii,mixed with some Betula platyphylla and Populus davidiana; sample plot Ⅱ and sample plot Ⅲ were also mainly composed of Larix gmelinii and mixed with little Betula platyphylla.The density differed greatly among the sample plots,which was in the order as sample plot Ⅰ（1 740 tree/hm2） 〉 sample plot Ⅲ（1 080 tree/hm2） 〉 sample plot Ⅱ（910 tree/hm2）.The distribution pattern of sample plotIand sample plot Ⅲ was aggregated distribution,while sample plot Ⅱ was random distribution.The complexity of species composition of the three plots was ordered as sample plot Ⅰ（23 species） 〉 sample plot Ⅲ （21 species） 〉 sample plot Ⅱ（19 species）.Species richness and species diversity indexes in the vertical community structure were both indicated as herb layer 〉 shrub layer 〉 arbor layer.Evenness index of the sample plots was mainly as herb layer 〉 shrub layer 〉 arbor layer,except for thai the Pielou index （JSW） of both sample plot Ⅰ and sample plot Ⅲ,and the Alatalo index of sample plot Ⅲ was shrub layer 〉 herb layer 〉 arbor layer.