【摘要】 Beta多样性能够度量物种组成的时空变化格局,其驱动因子(例如空间与环境)一直是生态学研究的热点之一。然而,林分结构作为森林群落重要的特征参数,其对木本植物beta多样性的驱动作用还知之甚少。本研究以云南纳板河热带季节雨林20ha动态样地的木本植物为研究对象,在不同取样尺度将beta多样性分解为物种周转组分和物种丰富度差异组分,通过基于距离矩阵的多元回归分析和方差分解,解析空间、环境和林分结构在beta多样性及其两个组分格局形成中的相对作用。结果表明:(1)Beta多样性、物种周转组分和物种丰富度差异组分随取样尺度的增大而减小,物种周转组分始终在beta多样性构成中占主导部分。(2)环境距离对beta多样性和物种周转组分具有相对较高的解释率,随着取样尺度增大,单纯的环境距离对beta多样性的解释率从8.8%增长到23.9%,对物种周转组分的解释率从5.1%增长到26.5%;而环境距离对物种丰富度差异组分几乎没有作用。(3)不同取样尺度林分结构距离对beta多样性均具有相对较高的解释率(11.3%-25.1%),并且对物种周转组分和物种丰富度差异组分始终保持一定的解释率。同时,无论是否包含林分结构距离作为解释变量,单纯的空间距离对beta多样性及其两个组分的解释率都很低。本研究支持环境过滤对beta多样性和物种周转组分的相对重要性随着取样尺度的增大而增大的观点,同时发现扩散限制在局域尺度beta多样性格局形成中的作用却十分有限。本研究进一步揭示了能够指示光的可利用性和异质性的林分结构,与地形、土壤等其他环境因子一样,也是beta多样性格局形成的重要驱动力,建议未来深入研究林分结构在木本植物多样性格局形成中的作用机制。更多还原

【Abstract】 Aims: Beta diversity measures the pattern of spatial and temporal changes in species composition. The factors driving beta diversity, such as spatial distance and environment conditions, are key topics in ecological research. However, as an important characteristic parameter of forest community, the driving effect of forest stand structure in shaping woody plants beta diversity remains largely unexplored. This study aims to address the contribution of forest stand structure,alongside space and environment, to beta diversity and its components.Methods: Focusing on woody plants in the 20 ha tropical seasonal rainforest dynamics plot in Nabanhe, Yunnan, this study decomposed beta diversity into two components: Species turnover and species richness difference, across different sampling scales. By using multivariate regression based on distance matrices and variance partitioning, we revealed the relative contributions of spatial, environmental, and forest stand structure factors in shaping beta diversity and its two components.Results: The results showed that:(1) beta diversity and its species turnover component and species richness difference component decreased with the increase increasing sampling scale, with species turnover consistently dominating beta diversity.(2) Environmental distance had a relatively high explanatory power for beta diversity and its species turnover component, with its influence increasing from 8.8% to 23.9% for beta diversity and from 5.1% to 26.5% for species turnover as the sampling scale expanded. However, environmental distance had little effect on species richness difference component.(3) Forest stand structure demonstrated relatively high explanatory power for beta diversity(11.3%-25.1%) and maintained a certain degree of explanatory power for both species turnover component and species richness difference component across all scales. At the same time, pure spatial distance, whether or not stand structure was included, had a low explanatory power for beta diversity and its components.Conclusion: This study supports the viewpoint that the relative importance of environmental filtering in beta diversity,particularly the species turnover component, increases with sampling scale. In contrast, dispersal limitation plays a limited role at local scales. This study further reveals that forest stand structure indicating the light availability and heterogeneity is also an important driving force for beta diversity, similar to environmental factors such as topography and soil. Future research should focus on elucidating the mechanisms by which stand structure influence woody plant beta diversity in the future.更多还原