桂西不同灌丛植物群落物种组成及其多样性

该研究通过野外设定样方、每木检尺的方法，调查了桂西9个市县的10种不同灌丛类型群落，分析了灌丛群落优势种重要值、物种组成、生长指标和物种多样性指数等生物学特征。结果表明：桂西灌丛资源丰富、分布广泛、类型多样，在调查的10个群落类型中，共有灌木树种87种，隶属于47科78属，以大戟科、蔷薇科和马鞭草科的树种较多；草本56种，隶属于31科48属，以禾本科、菊科和蔷薇科为主。灌丛群落主要分为灌木层和草本层，灌木层盖度为30％~70％，灌木的平均高度介于0.75~3.25 m之间，一般不超过5 m；草本层盖度为3％~90％，草本的平均高度在0.4~1.3 m之间，一般在1 m以下。不同灌丛群落的优势种重要值、物种多样性均不同，单优势种群落的优势种重要值普遍较高；而多优势种群落的物种多样性指数较高，即多优势种群落的物种数量多、分布均匀、结构更加复杂和稳定。物种丰富度S、多样性指数H′、优势度指数D和均匀度指数E之间存在显著的正相关性。综合分析，群落9(白栎＋马桑＋火棘灌丛)和群落10(黄荆＋灰毛浆果楝灌丛)的组成丰富、多样性水平较高。

Species composition and diversity of different shrub communities in West Guangxi

Ten different shrub communities distributed in nine counties of West Guangxi were investigated through field survey. The analysis of their importance values(IV), species compositions, biomass and diversity showed that diverse shrubs were widespread in the areas with 87 shrub species belong to 78 genera and 47 families, and 56 kinds of herbs belong to 48 genera and 31 families, being recorded. Species from Eup horbiaceae, Rosaceae, Verbenaceae dominated the communities. The communities mainly contained shrub and herb layers. The shrub layer coverage ranged from 30% to 70%, average height 0.75 to 3.25 m, few outliers with height > 5 m. The herb layer coverage was 3% to 90%, average height 0.4 to 1.3 m, often below 1 m. Dominant species'' important value, diversity and grass growth varied among different shrub populations, and monodominant communities generally had higher dominant species'' important value than polydominant communities, while the latter had higher diversity index, more species, representing even distribution and complex stable structures. Species'' richness, shannon indices, dominance indices and evenness indices were positively and significantly correlated. Community No. 9(Quercus fabri + Coriaria nepalens + Pyracantha fortuneana)and No. 10(Vitex negundo + Cipadessa baccifera)had higher species richness and diversity. This provides the information for shrub resoruce conservation in West Guangxi.