黄土高原半干旱区侧柏人工林群落物种多样性研究

Study on Species Diversity of Platycladus orientalis Plantation Community in Semiarid Region of Loess Plateau

以晋西吕梁山黄土高原半干旱区侧柏人工林为研究对象,对林内植物种类进行野外调查结果表明,侧柏林下共有维管束植物39种,隶属于16科33属。利用Shannon-wiener指数、Evenness指数和Richness指数,对不同林分密度级侧柏人工林群落物种多样性进行分析,探讨黄土高原半干旱区侧柏人工林林分密度与群落物种多样性的关系。结果为:①林分密度的变化对于乔木层和灌木层物种数量影响不大,当密度为2250株.hm-2时,草本层物种丰富度达到最大值。②林分密度对灌木层和草本层的多样性指数变化有一定的影响。当林分密度为1375株.hm-2和2250株.hm-2时,乔木层、灌木层和草本层的物种多样性指数较大,群落相对稳定。③除密度为3000株.hm-2的林分外,其余4个林分密度的乔木层、灌木层和草本层的均匀度指数变化趋势同丰富度指数和多样性指数基本一致。④研究区的侧柏人工林造林密度选择2250株.hm-2或1375株.hm-2比较适宜。

Taking Platycladus orientalis plantation in semiarid region of Loess Plateau as research objec-tives, the field work focus on plant species inside the plantation ind cies, belonging to 33 genera of 16 families. Then Shannon-wiener index, Evenness index and Richness index were adopted to analyze the species diversity of the plantation community at different grades of stand density, and to discuss the relationship between stand density and community species diversity. The re-sults showed that firstly, stand density had little significant impact on species quantity of both arbor and shrub layers. The richness of the herb layer amounted to the maximum at the density of 2250（stem·hm^-2） ;secondly, stand density had certain impact on diversity index change of shrub ＆ herb layers. When the density was 1375 （stem·hm^-2） and 2 250 （stem·hm^-2）, the species diversity indexes of arbor,shrub and herb layers were relative bigger and the community tended to be stable; thirdly, except for density of 3 000 （ stem · hm^-2 ）, the evenness index of the remanent stands tended to be same as the richness and diversity indexes; fourthly, data analysis revealed that 2 250 （stem·hm^-2） and 1100 （stem · hm^-2） density were the most suitable densities for Platycladus orientalis plantation.