桂林岩溶石山青冈群落植物功能性状的尺度变化与关联

研究植物功能性状在不同尺度的变异和关联,对于揭示植物对环境的适应策略和群落构建规律具有重要意义。以岩溶石山青冈群落为研究对象,测量了研究区内20个样方74种木本植物的叶面积、比叶面积和木材密度3个功能性状值,利用性状梯度分析法分析了3个性状在群落内部(α组分)及群落间(β组分)的变异格局及相关性。结果表明:(1)群落内3个植物功能性状的α值范围均大于β值范围,即物种相对于共生物种性状值的变化大于沿着群落平均性状梯度的变化。(2)植物功能性状比叶面积的种内差异引起的变化小于群落水平。(3)叶面积与比叶面积、比叶面积与木材密度、叶面积与木材密度的β组分相关性均最强,而α组分间无相关性或相关性较弱,即叶面积与比叶面积、比叶面积与木材密度、叶面积与木材密度两两性状间的相关性在群落间的依赖程度比群落内共生物种的依赖性要强,暗示物种在群落内和群落间采取不同的生态策略来适应环境。

Scale variation and correlation of plant functional traits in the dominant Cyclobalanopsis glauca community in the karst area of Guilin city, Southwest China

Knowing the variation patterns in plant functional traits and the correlations between different traits across scales have strong ecological implications for revealing the adaptation strategies of plants to the changing environment, and the underlying mechanisms of community assembly. Our objective is to explore variations and correlations of plant functional traits at the species and community levels in Cyclobalanopsis glauca community in the karst area of Guilin city in order to improve our understanding about community assembly mechanisms. We investigated species composition of 20 plots in Cyclobalanopsis glauca community in the karst area of Guilin city, Southwest China and quantified three continuous functional traits (leaf area, specific leaf area, and wood density) for 74 woody species in these plots. We calculated the species abundance-weighted mean community trait values and used trait-gradient analyses (TGA) to partition these three species functional trais into alpha (within site) and beta (among-site) components, and then used Pearson correlation coefficient to analyze the correlations between these three plant functional traits at different scales. The results show that the alpha trait components consistently varied more widely than beta components, meaning that trait variation among species within plots was wider than variation in the mean trait values of plots where species typically grow. The specific leaf area within species had lower variation than that in the community level. There were strong correlations between leaf area and specific leaf area, between specific leaf area and wood density, and between leaf area and wood density in the beta component, whereas no strong correlation or even no correlation was found between leaf area and specific leaf area, between specific leaf area and wood density, and between leaf area and wood density in the alpha components. This suggested that the relationship between plant functional traits within the community in which they occur is stronger than that between plant functional traits of co-occurring species within the community. Also, this implied that species adopted different strategies to adapt to the change in habitats within a community and between communities in Cyclobalanopsis glauca community in the karst area of Guilin city.