北京西山地区侧柏游憩林群落结构及植物多样性

为了从群落生态学角度科学经营北京西山地区侧柏Platycladus orientalis游憩林，采用区系成分分析法、系统聚类法、方差均值比率法及物种丰富度指数（R，D_gl，D_ma），多样性指数（D_si，D_sh，D_mc），均匀度指数（J_si，J_sh，E_a），群落总体多样性指数分别对其植物组成与区系、群落垂直结构、种群空间分布格局及植物多样性进行了系统研究。结果表明：侧柏游憩林群落植物种类较为丰富，包括32科59属63种高等维管束植物，且反映出以温带成分为主的植物区系特点。群落垂直层次分化明显，理论上可定量划分为乔木层、灌木层和草本层3个层次，且各层优势种群突出。建群种侧柏趋于随机分布（C＜1，t＜t_0.05），而林下植被（荆条Vitex negundo var. heterophylla，孩儿拳头Grewia biloba，求米草Oplismenus undulatifolius等）则呈不同程度的聚集分布（C＞1，t＞t_0.01）。不同生长型间物种丰富度及多样性大小规律为：灌木＞乔木＞草本（P＜0.05），乔木和灌木均匀度均大于草本（P＜0.05）。不同生长型对群落总体多样性的贡献率分别为乔木0.696，灌木0.204和草本0.100。低山阴坡厚土可作为营建侧柏游憩林的优先选择立地类型，同时建议营建相对低密度的群落以满足游客对游憩空间及生物多样性的需求。图2表4参22

Community structure and plant diversity of a Platycladus orientalis recreational plantation in West Mountain area of Beijing

To scientifically manage Platycladus orientalis recreational plantations using principles of community ecology in West Mountainou area of Beijing, characteristics of plant composition, vertical structure, spatial distribution patterns, and plant diversity were systematically studied using componential analysis, hierarchical clustering, the variance to mean method, richness indices （R, Dgl, Dma）, diversity indices （Dsi, Dsh, Dmc）, evenness indices （Jsi, Jsh, Ea）, and total community diversity indices. Higher vascular plants in this community revealed 32 families, 59 genera, and 63 species reflecting the floral features of a temperate zone. Community stratification was distinct and quantitatively divided into three major theoretical layers： tree, shrub, and herb, with dominant populations in each layer. P. orientalis tended to a random distribution （C1, tt0.05）, whereas undergrowth, such as Vitex negundo var. heterophylla, Grewia biloba, and Oplismenus undulatifolius, clumped （C1, tt0.01） with unification of various degrees. Species richness and diversity by layer were： shrubtreeherb （P0.05） with species evenness of： tree and shrub herb （P0.05）. Contribution rates to general community diversity were： tree： 0.696, shrub： 0.204, and herb： 0.100. For the development of plant species diversity, shady slope was a priority. Also, to create recreational space in plantations with biodiversity, a low density （756-933 plants·hm-2）, which helped maintain a higher plant species diversity, was recommended.