桂林岩溶石山青冈群落植物功能性状的种间和种内变异研究

Interspecific and intraspecific variation of functional traits of woody species in the dominant Cyclobalanopsis glauca community in the karst area of Guilin city, Southwest China

研究植物功能性状的种间和种内变异,有助于揭示植物对环境的适应策略及其群落构建机制研究。以桂林岩溶石山青冈群落主要木本植物为研究对象,选取叶干物质含量(LDMC)、叶厚度(LT)、比叶面积(SLA)和木材密度(WD) 4个功能性状,采用混合线性模型结合方差分解方法对其在种内和种间尺度的变异程度和相对贡献进行分析,同时运用零模型方法探讨驱动岩溶石山青冈群落构建的潜在机制。结果表明:(1)LDMC,LT,SLA和WD这4个性状在种内和种间水平上均存在不同程度的变异幅度,种间变异大于种内变异,但种内变异亦不容忽略。(2)零模型检验表明,将种内变异纳入考虑的环境过滤检测得到改善,基于个体性状值的尺度考虑群落构建机制研究是必要的。(3)对于桂林岩溶石山青冈群落,环境过滤作用确实是群落构建的重要驱动机制,与相似性限制作用和随机作用共同塑造了以青冈为优势物种的群落构建。

Interspecific and intraspecific variations of plant functional traits help reveal plant adaptation strategies to the environment and to mechanism of community assembly. In this study, we investigated 4 key functional traits of 105 species and 4190 individuals to understand changes in woody plant functional traits of the Cyclobalanopsis glauca community in the karst area, Guilin city. These functional traits were leaf dry matter content(LDMC), leaf thickness(LT), specific leaf area(SLA), and wood density(WD). Combined with the variance decomposition method, we performed the mixed linear models to analyze the degree and proportion of interspecific and intraspecific variation of functional traits. Based on it, we used the null model method to detect the potential driving mechanism in community construction by considering or not considering the variability of intraspecific variation of functional traits. These results suggest that:(1) the variation of the four plant functional traits was dominated by interspecific variation, and the intraspecific variation cannot be ignored.(2) The nullmodel test shows that the environmental filtering test at the individual level is improved. Community assembly seems to affect traits on the scale of individuals.(3) For the Cyclobalanopsis glauca community in the karst area of Guilin city, environmental filtering is indeed an important driving mechanism for community assembly. Together with similarity restriction and random effects, it shapes the community construction with Cyclobalanopsis as the dominant species.