Species abundance distributions (SADs) characterise the distribution of individuals among species. SADs have rarely been explored on islands and the ecological processes shaping SADs are still not fully understood. Notably, the relative importance of disturbance regime in shaping plant SADs remains poorly known. We investigate the relative importance of disturbance regime and island geography on the shape of SADs. We computed SADs for local tree communities in 1‐ha forest plots on 20 tropical islands in the Indo‐Pacific region. We used generalized linear models to analyse how the shape parameter of the gambin SAD model was related to the number of trees and the number of species. Regression analyses were also used to investigate how the shape of SADs, the number of trees and the number of species were related to cyclone disturbance (power dissipation index) and geography (island area and isolation), with direct and indirect (i.e. through the number of trees and species) effects assessed using variance partitioning. Cyclone disturbance was the best predictor of the shape of SADs, with higher power dissipation index producing more lognormal‐like distributions. This effect was mostly due to cyclones increasing the number of trees and decreasing the number of species. Island area affected the shape of SADs through its effect on the number of species, and larger islands were associated with higher species richness and more logseries‐like distributions. The effect of cyclones was stronger on smaller islands. Our results illustrate that disturbances can affect SADs in complex ways; directly and indirectly by impacting the number of species and individuals in communities, and these effects may be moderated by island‐specific characteristics, such as island area or isolation. Our results therefore suggest that multiple, interacting processes shape SADs and that studying SADs has the potential to contribute important new insights to the field of island biogeography.

中文翻译：

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热带气旋和岛屿地区塑造当地树木群落的物种丰富度分布

物种丰度分布（SADs）表征个体在物种之间的分布。很少在岛屿上探索过SAD，而且对SAD形成的生态过程仍未完全了解。值得注意的是，干扰机制在塑造植物SAD中的相对重要性仍然知之甚少。我们调查了扰动机制和岛屿地理对SAD形状的相对重要性。我们计算了印度太平洋地区20个热带岛屿上1公顷森林地中当地树木群落的SAD。我们使用广义线性模型来分析gambin SAD模型的形状参数与树木数量和物种数量之间的关系。回归分析还用于调查SAD的形状，树木的数量和种类的数量与旋风扰动（功耗指数）和地理（岛屿面积和隔离）有关，并使用方差划分评估了直接和间接（即通过树木和物种的数量）的影响。旋风扰动是SAD形状的最佳预测指标，功率损耗指数越高，产生的对数正态分布越多。这种影响主要是由于旋风增加了树木的数量，减少了物种的数量。岛屿地区通过影响物种数量来影响SAD的形状，而更大的岛屿则与更高的物种丰富度和更多的对数级分布相关。在较小的岛屿上，旋风的影响更大。我们的结果表明，干扰会以复杂的方式影响SAD。通过直接或间接地影响社区中物种和个体的数量，这些影响可能会因特定于岛屿的特征（如岛屿面积或孤立性）而有所缓解。因此，我们的结果表明，多个相互作用的过程可以形成SAD，并且研究SAD具有潜力为岛屿生物地理学领域提供重要的新见解。