不同密度云杉林下草本植物多样性

Diversity of understory herbs in Picea forests with different stand densities

为了解寒温性针叶林林分密度与林下草本植物多样性的关联性,在山西省庞泉沟国家级自然保护区,选择以云杉Picea林为代表的寒温性针叶林,在不同密度的林分中设置样地,调查林下草本植物的物种组成,分析林下草本植物的多样性,并对林分密度和多样性指数进行相关分析。结果表明:1在研究区的云杉林中共调查到37种草本植物,隶属于18个科35个属。2云杉林下草本植物多样性指数(Simpson指数、Shannon-Wiener指数和Pielou均匀度指数)随着林分密度的增加而减小。当林分密度为475株·hm-2时,Simpson指数、Shannon-Wiener多样性指数和Pielou均匀度指数分别为0.82,1.97和0.71;当林分密度为1 000株·hm-2时,Simpson指数、Shannon-Wiener多样性指数和Pielou均匀度指数分别为0.54,1.18和0.39。3不同密度的云杉林中,草本植物丰富度指数没有明显的变化规律。研究认为:在以云杉为主要树种的寒温性针叶林中,林分密度对林下草本植物的多样性指数有明显的影响,随着林分密度的增加多样性指数减小。

To explain the relevance of stand density and understory vegetation diversity in cold, temperate coniferous forests, the Picea （spruce） forests in the Pangquangou Nature Reserve of Guandi Mountain, Shanxi Province were selected as a representative study. In the experiment, twenty seven sample plots were set in stands with nine stand densities （475, 500, 525, 675, 700, 800, 900, 925 and 1 000 trees.hm-2） and three replicates. The sample plot area is 400 m2 （20 m × 20 m）. Species composition of understory herbaceous plants was determined in all replicates and the relevance between stand density and diversity index was analyzed using Simpson, Shannon-Wiener Diversity, Pielou Evenness Indexes and Richness. Results showed （1） 37 species of herbs belonging to 35 genera in 18 families. （2） The diversity indexes of herbaceous plants decreased with an increase in stand density： with a stand density of 475 trees .hm^-2 the Simpson Index was 0.82, the Shannon-Wiener Index was 1.97, and the Pielou Index was 0.71; whereas, at 1 000 trees.hm^-2 the Simpson Index was 0.54, the Shannon-Wiener Index was 1.18, and the Pielou Index was 0.39. （3） With different stand densities, the Richness of herbaceous plants ranged from 14 to 23. Thus, in cold, temperate coniferous forests with Picea as the main species, the diversity index of understory herbs decreased with a stand density increase. [ Ch, 3 fig. 3 tab. 23 ref]