植物群落的构建机制长期以来都是生态学研究的热点问题之一。影响群落构建的因素有多种，竞争是其中最重要的生态学过程之一。通常探讨竞争如何影响群落构建都基于这样的假设，即物种之间的竞争是由性状相似和谱系相近驱动的，竞争导致共存物种的性状和谱系结构趋异。但是，部分研究的结果与这一理论相悖，认为竞争是由性状相异所驱动，竞争也可能导致性状和谱系趋同。然而，这两种假设都尚未得到充分验证。本研究以广东省黑石顶南亚热带常绿阔叶林50 ha样地为研究对象，通过野外实验（130个物种）和温室控制实验（4个物种）的手段，结合环境梯度研究物种之间根系性状距离和谱系距离与竞争强度的关系，从而揭示物种之间根系竞争作用的驱动因素，以及驱动因素在不同环境下如何变化，为研究竞争作用如何影响群落构建提供重要证据。

Understanding the mechanisms of plant community assembly is one of the fundamental aims in community ecology. The processes of community assembly can be regulated by many factors, and competition is one of the most important factors in controlling community assembly. Many studies related to competition were based on the common assumption that competition was driven by trait similarity and relatedness closeness of co-occurring species, which led to functional and phylogenetical divergence. However, some studies also found inconsistent results. They suggested that competition was driven by hierarchy of traits, which may result in functional convergence of co-occurring species. Overall, the knowledge is limited on what drives competition, and how competition controls the community structure. In this study, we attempt to investigate the relationships between root trait distances and phylogeny distances and competition intensity across environmental gradients for subtropical tree species at Heishiding 50 ha forest dynamics plot, using field (130 species) and greenhouse (4 species) experiments, which can explain what factors drive the competition, and how they respond to the environmental change. Our study can provide essential evidences on how competition regulates community assembly.