桂西地区南亚热带落叶栎林群落组成及物种多样性研究

Community Composition and Species Diversity of Deciduous Oak Forest in South Subtropical Region of West Guangxi

落叶栎林是桂西地区南亚热带的典型次生林,也是该区域落叶阔叶林的重要群系组。该研究采用典型样方法对桂西地区落叶栎林群落进行调查,分析了该区域落叶栎林群落的物种组成、区系成分、物种多样性特征及其与地形因子的关系,为桂西地区南亚热带植物多样性保护与恢复提供依据。结果显示:(1)研究区落叶栎林群落维管束植物共计269种,隶属80科178属。(2)种子植物区系以热带成分为主,同时表现出一定程度的温带过渡性质。(3)聚类分析表明,调查的落叶栎林群落可分为云南波罗栎林、栓皮栎林、白栎林、麻栎林4种林分类型,其中以白栎林群落的物种多样性最高,且灌木层的物种多样性显著高于乔木层和草本层。(4)RDA分析显示,落叶栎林群落不同层次物种多样性的差异受地形因子的影响,多样性指标与经度、纬度、海拔之间具有明显的相关性(P<0.05),其中乔木层物种多样性主要与经度、纬度呈显著的相关性,灌木层物种多样性与纬度、海拔相关,草本层物种多样性与经度、纬度、海拔之间均有相关性。

Deciduous oak forest is a typical secondary forest and an important group of deciduous forest in west Guangxi.In this study,we used a typical sample method to investigate deciduous oak forest community in West Guangxi,and analyzed the species composition,floristic components,species diversity characteristics and the relationship between the deciduous oak forest community and topographic factors.This study can provide scientific basis for the conservation and restoration of plant diversity in the south subtropical region of West Guangxi.Results showed that:(1)there were 269 species of vascular plants in deciduous oak forest,belonging to 178 genera and 80 families.(2)The spermatophyte flora was mainly influenced by Pantropic and North Temperate and its variations,which reflected a certain degree of transitional nature.(3)Based on cluster analysis,the deciduous oak forests could be classified into 4 types:Quercus yunnanensis forest,Quercus variabilis forest,Quercus fabri forest and Quercus acutissima forest.The species diversity of Q.fabri forest was the highest among all deciduous oak forests,and the diversity index of the shrub layer was significantly higher than the tree layer and herb layer.(4)The DCA ordination results indicated that longitude,latitude and altitude were the important topographic factors affecting the species diversity in different levels of deciduous oak forest community.The species diversity of tree layer was significantly correlated with longitude and latitude,shrub layer species diversity was correlated with latitude and altitude,and herb layer species diversity was correlated with longitude,latitude and altitude.