西藏色季拉山林线植物群落多样性格局及林线的稳定性  

Plant diversity pattern and stability of the timberline community on Sejila Mountain in Tibet,western China

作　　者：杨小林[1] 崔国发[1] 任青山[2] 王景升[3] 黄瑜[2] 

机构地区：[1]北京林业大学自然保护区学院 [2]中国人民大学环境学院 [3]西藏农牧学院资源与环境学院

出　　处：《北京林业大学学报》2008年第1期14-20,共7页Journal of Beijing Forestry University

基　　金：国家自然科学基金(30571484);教育部重点基金资助项目(104052)。

摘　　要：通过样地调查,采用α和β指数对西藏东南部地区色季拉山林线森林植物群落类型的多样性特征进行了分析。结果表明:①色季拉山海拔和坡向决定了林线植物群落分布类型与物种组成,林线群落物种多样性程度为阳坡高于阴坡。②阳坡林线森林群落各层次多样性指数表现为:乔木层<灌木层<草本层的规律;而阴坡则表现出乔木层<草本层<灌木层的规律。③物种替代率为阴坡高于阳坡;在林线过渡带边缘物种替代率高且物种种类变化明显,而在林线过渡带区域内物种替代率变化幅度较小,表现出林线边缘环境对物种具有较强的筛选作用。④林线以下,群落物种多样性变化明显,物种多样性指数的大小主要受草本植物种类的影响。林线生态过渡带结束,阴、阳坡的物种组成差异缩小,植被群落类型也相似。Through plot investigation, using α and β diversity indices, this paper analyzes the features of plant diversity of the timberline forest community on Sejila Mountain in the southeast of Tibet, western China. Results were as the followings ： 1 ） The altitude and exposure of Sejila Mountain determined the distribution types and species structures of the timberline plant community. The plant diversity of the timberline community on the sunny slope was higher than that on the shady slope. 2） The diversity indices of different layers of the timberline community on the sunny slope showed a law of tree layer 〈 shrub layer 〈 herb layer, while on the shady slope, it was tree layer 〈 herb layer 〈 shrub layer. 3） The species replacement rate on the shady slope was higher than that on the sunny slope. On the edge of the timberline transition zone, the species replacement rate was relatively higher and the species structure changed apparently, while in the transition zone, the replacement rate was relatively lower, showing that the environment on the edge of the timberline strongly selected the species. 4 ） The species diversity of the communities under the timberline changed apparently. The species diversity indices were mainly influenced by the species of herbs. After the timberline ecological transition zone, the species structure differences between the sunny slope and the shady one decreased and the types of vegetation communities also became similar.

关 键 词：西藏 林线 群落 多样性指数 稳定性 

分 类 号：S718.54[农业科学—林学]