华北地区主要灌丛群落物种组成及系统发育结构特征

灌丛在中国北方广泛分布, 研究其物种组成特征及构建机制对植被恢复有重要意义。群落系统发育结构能有效反映群落组成的生态过程, 对揭示群落构建机制具有重要作用。该研究利用华北地区自然植物群落资源综合考察数据库的灌丛数据, 分析了中国华北地区主要灌丛群落的分布情况、物种组成及其系统发育结构特征。同时, 结合WorldClim数据库中的气候因子利用逐步回归和一般线性模型分析了气温和降水对灌丛不同垂直结构层物种系统发育结构特征的影响。经统计, 共调查木本植物75科207属570种; 草本植物99科491属1 221种。按植被型和群系类型分类后, 共有5种植被型, 195个群系, 其中分布最多的群系类型为虎榛子(Ostryopsis davidiana)灌丛、荆条(Vitex negundo var. heterophylla)灌丛、荆条+酸枣(Ziziphus jujuba)灌丛和沙棘(Hippophae rhamnoides)灌丛。整体上, 草本层的物种丰富度高于灌木层。草本层的系统发育结构表现为发散模式, 而灌木层的系统发育结构表现为聚集模式, 且不同植被型灌丛的系统发育结构不同。气候因子的变化对灌木层和草本层系统发育结构都表现出了明显的影响, 但对灌木层的影响要强于对草本层的影响, 且气候因子和植被型、群系类型都有明显的交互作用。分析结果表明, 区域尺度上气温和降水的变化会影响灌丛群落不同结构层的系统发育结构特征, 且对不同的植被型和群系类型的影响不同。

Species composition and phylogenetic structure of major shrublands in North China

Aims Shrublands are widely distributed in the North China. Understanding species composition and community assembly of the shrublands has important implications for promoting vegetation restoration in this area. Community phylogenetic structure can reflect community assembly process. In the present study, we explored the distribution patterns, species composition and phylogenetic structure of major shrubland types from North China, and then analyzed the effects of temperature and precipitation on these patterns with the help of the WorldClim dataset.
Methods A total 2 331 plots were setup to survey species composition and phylogenetic structure of major shrubland types in North China. A multiple stepwise regression was used to determine the effects of climatic factors on community phylogenetic structure, and a generalize linear model was used to test the interaction of environmental factors and formation types or vegetation types.
Important findings A total of 570 woody species belonging to 207 genera from 75 families, together with 1 221 herb species belonging to 491 genera from 99 families were recorded during the investigation. Five vegetation types and 195 formation types were identified, and the major formation types were Ostryopsis davidiana formation, Vitex negundo var. heterophylla, Vitex negundo var. heterophylla + Hippophae rhamnoides and Hippophae rhamnoides formation. The species richness of herb layer was higher than that of shrub layer. The phylogenetic structure was over-dispersed for herb layer and was convergent for shrub layer. The phylogenetic structure differed remarkable among different vegetation types. The phylogenetic structures of both shrub and herb layers were significantly correlated with climatic factors, and the interaction of climate factors and vegetation types or formation types as well. Our results indicates that large scale variation of climatic factors regulate community phylogenetic structure of different layers in shrub community, and the effects depend on vegetation types and formation types.