In plant communities, some mechanisms maintain differences in species' abundances, while other mechanisms promote coexistence. Asymmetry in conspecific negative density dependence (CNDD) and/or habitat preference is hypothesized to shape relative species abundance, whereas community compensatory trends (CCTs) induced by community-level CNDD and heterospecific facilitation are hypothesized to promote coexistence. We use survey data from three 1-ha permanent dynamic plots in a subtropical forest over the course of a decade to find out which of these processes are important and at which life-history stages (the seedling, sapling, and juvenile stages) they exert their effects. CNDD was not related to abundance in any of the life-history stages. Suitable habitats positively influenced plant abundance at all tested life stages, but especially so for juveniles. Community-level CNDD of seedling neighbors was detected at the seedling stage, while heterospecific facilitation was detected across all tested life-history stages. A CCT in seedling survival was detected, but there was no evidence for such trends across the other life-history stages. Altogether, our results suggest that habitat specificity increases the rarity of species, whereas a CCT at the seedling stage, which is likely to be induced by CNDD and heterospecific facilitation, enables such species to maintain their populations.

在植物群落中，某些机制维持物种丰度的差异，而其他机制则促进共存。假设在特定物种的负密度依赖性（CNDD）和/或栖息地偏好方面存在不对称性，以塑造相对物种的丰富度，而在群落水平的CNDD和异种特异性促进作用下引起的群落补偿性趋势（CCT）被认为可以促进共存。我们使用十年来在亚热带森林中的三个1公顷永久性动态地块的调查数据中，找出其中哪些过程很重要，以及它们在哪个生命历史阶段（幼苗，幼树和幼年阶段）发挥作用他们的影响。CNDD与任何生命历史阶段的丰度都不相关。在所有测试的生命阶段，合适的栖息地都会对植物的丰度产生积极影响，但对于青少年尤其如此。在苗期检测到邻域社区水平的CNDD，而在所有测试的生活史阶段均检测到异种易化性。在幼苗存活中检测到CCT，但没有证据表明在其他生命史阶段有这种趋势。总而言之，我们的结果表明，栖息地特异性增加了物种的稀有性，而幼苗阶段的CCT（很可能是由CNDD和异源特异性促进作用诱导的）使此类物种得以维持种群。但是没有证据表明在其他生活史阶段有这种趋势。总而言之，我们的结果表明，栖息地特异性增加了物种的稀有性，而幼苗阶段的CCT（很可能是由CNDD和异源特异性促进作用诱导的）使此类物种得以维持种群。但是没有证据表明在其他生活史阶段有这种趋势。总而言之，我们的结果表明，栖息地特异性增加了物种的稀有性，而幼苗阶段的CCT（很可能是由CNDD和异源特异性促进作用诱导的）使此类物种得以维持种群。