BACKGROUND AND AIMS There is a paucity of empirical research and a lack of predictive models concerning the interplay between spatial scale and disturbance as they affect the structure and assembly of plant communities. We proposed and tested a trait dispersion-based conceptual model hypothesizing that disturbance reinforces assembly processes differentially across spatial scales. Disturbance would reinforce functional divergence at the small scale (neighbourhood), would not affect functional dispersion at the intermediate scale (patch) and would reinforce functional convergence at the large scale (site). We also evaluated functional and species richness of native and exotic plants to infer underlying processes. Native and exotic species richness were expected to increase and decrease with disturbance, respectively, at the neighbourhood scale, and to show similar associations with disturbance at the patch (concave) and site (negative) scales. METHODS In an arid shrubland, we estimated species richness and functional dispersion and richness within 1-m 2 quadrats (neighbourhood) nested within 100-m 2 plots (patch) along a small-scale natural disturbance gradient caused by an endemic fossorial rodent. Data for the site scale (2500-m 2 plots) was taken from a prior study. We also tested the conceptual model through a quantitative literature review and a meta-analysis. KEY RESULTS As spatial scale increased, disturbance sequentially promoted functional divergence, random trait dispersion and functional convergence. Functional richness was unaffected by disturbance across spatial scales. Disturbance favoured natives over exotics at the neighbourhood scale, while both decreased under high disturbance at the patch and site scales. CONCLUSIONS Results supported the hypothesis that disturbance reinforces assembly processes differentially across scales and hampers plant invasion. The quantitative literature review and the meta-analysis supported most of the model predictions.

中文翻译：

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扰动在空间尺度上以不同的方式加强了社区组装过程

背景和目标 缺乏实证研究，也缺乏关于空间尺度和干扰之间相互作用的预测模型，因为它们影响植物群落的结构和组装。我们提出并测试了一个基于特征分散的概念模型，假设干扰会在空间尺度上以不同的方式加强装配过程。干扰会加强小尺度（邻域）的功能发散，不会影响中间尺度（补丁）的功能分散，并会加强大尺度（场地）的功能收敛。我们还评估了本地和外来植物的功能和物种丰富度，以推断潜在的过程。本地和外来物种的丰富度预计分别在邻域尺度上随着干扰而增加和减少，并在斑块（凹面）和部位（负）尺度上显示与干扰的类似关联。方法 在干旱的灌木林中，我们估计了 1 米 2 样方（邻域）内的物种丰富度、功能分散和丰富度，这些样方（邻域）嵌套在 100 米 2 地块（斑块）内，沿着由地方性化石啮齿动物引起的小规模自然干扰梯度。场地规模（2500 米 2 地块）的数据取自先前的研究。我们还通过定量文献回顾和荟萃分析测试了概念模型。主要结果随着空间尺度的增加，干扰依次促进功能发散、随机性状分散和功能收敛。功能丰富性不受空间尺度干扰的影响。在邻里范围内，扰乱有利于本地人而不是外来人，而在斑块和场地尺度的高扰动下两者均下降。结论 结果支持以下假设，即干扰会在不同尺度上以不同的方式加强组装过程并阻碍植物入侵。定量文献综述和荟萃分析支持大多数模型预测。