旱泉沟流域次生林演替过程中种群格局动态

对旱泉沟流域的植被种类组成、物种多样性和物种重要值进行调查分析，采用TWINSPAN对旱泉沟流域次生植物群落进行数量分类，从植物群系组成、植物群落之间的生态关系方面，研究旱泉沟流域封山禁牧区植被群落的分布格局，初步探讨乔木树种的演替趋势。研究结果表明：1）采用TWINSPAN数量分类方法，将植被划分为7个群落类型；2）从群落Ⅰ到群落Ⅶ, 乔木、灌木、草本的Simpson优势度指数基本持平，Shannon Wiener多样性指数为乔木<灌木<草本，Pielou均匀度指数为乔木>草本>灌木，物种丰富度逐渐升高。群落的物种组成和空间结构逐渐复杂化，并趋于稳定；3）次生林的演替序列为山杨树Populus davidiana→桦树Betula platyphylla→青海云杉Pica crassifolia，其自然演替顶级为青海云杉。

Study on dynamics succession pattern of secondary forest in Hanquangou valley of Gansu Province

Based on the investigation on the composition of plant species, plant diversity and important value of species in the secondary plant community in Hanquangou valley of Gansu Province, the community was classified by using two way indicator species analysis, the spatial distribution pattern of plant populations and the succession tendency of tree species was studied. The results showed that 1) the plant community could be classified into 7 types;2) their restoration degrees ranged from PhaseⅠto Phase Ⅶ with similar Simpson dominance index of tree layer, shrub layer and herb layer; as for the Shannon Wiener diversity index, it was tree layerherb layer>shrub layer, and the species richness gradually increased from PhaseⅠto Phase Ⅶ. The species composition and the spatial structure of the community gradually become complication and stable;3) the succession sequence was from aspen, birch to Qinghai spruce.