广西大青山次生林的群落特征及主要乔木种群的空间分布格局

本文依托广西友谊关森林生态系统国家定位观测研究站在大青山设置的1 ha长期监测样地, 分析了森林群落的物种组成、区系特征及乔木种群的径级结构, 并用点格局分析方法的O-ring统计对主要乔木植物种群的空间分布格局及其空间关联性进行了研究, 旨在深入探讨该区域次生林的物种多样性特点及其维持机制, 分析影响优势树种空间分布格局的可能因素。大青山次生林共调查到植物109种, 其中乔木58种、灌木29种、草本22种, 樟科为样地内物种最丰富的科, 区系组成以泛热带成分为主; 乔木树种的径级结构接近倒“J”形, 主要种群的个体集中分布于中小径级范围(1-5 cm), 林分结构合理, 更新良好。从物种多度、胸高断面积和重要值来看, 大叶栎(Quercus griffithii)和锈毛梭子果(Eberhardtia aurata)是群落中的共优种, 其个体数占总个体数的30.8%, 鸭公树(Neolitsea chuii)、广东琼楠(Beilschmiedia fordii)和尖连蕊茶(Camellia cuspidata)为群落的主要伴生树种。用完全随机模型不排除生境异质性的条件下, 主要种群多数呈聚集分布; 用异质性随机模型排除生境异质性的条件下, 主要种群的聚集程度显著下降, 仅在小尺度上呈聚集分布; 主要树种均在一定尺度上表现为两两间正相关, 且在0-50 m的大部分尺度上显示出相互独立的特点, 没有表现出负相关。

Community characteristics and spatial distribution of dominant tree species in a secondary forest of Daqing Mountains,southwestern Guangxi,China

In order to determine species characteristics and the factors affecting distribution patterns of dominant tree species of secondary forests in Daqing Mountains, we analyzed community composition, DBH size structure, species distribution and spatial correlations using a point pattern analysis of O-ring statistical method. There were a total of 109 species including 58 tree species, 29 shrub species and 22 herb species in a 1 ha plot. The floristic composition was pan-tropical with Quercus griffithii and Eberhardtia aurata as the co-dominant species. These two species accounted for 30.8% of the total number of individuals. Neolitsea chuii, Beilschmiedia fordii and Camellia cuspidate were the secondary tree species of the community. The DBH size structure of the populations showed a reverse J-shaped pattern with a greater number of small diameter (1-5 cm) individuals. Species spatial distribution with environmental heterogeneity was aggregated but decreased significantly with increasing spatial scales. Spatial distribution and heterogeneity were independent at most spatial scales among the main species populations.