Although woody plant encroachment of tropical forest ecosystems has been related to altered disturbance regimes, its impacts on the nearest neighborhood structures and community phylogenetics are still poorly understood. Streblus macrophyllus is a light-demanding species during its early life stages and is shade-tolerant as a mature tree. S. macrophyllus can be found in tropical karst evergreen forests in northern Vietnam. It often regenerates at high densities in anthropogenic disturbed forest stands. To understand the structural patterns of disturbed forests encroached by S. macrophyllus at different abundance levels, three fully mapped 1-ha plots were established in Cuc Phuong National Park. Methods considering the phylogenetic community and nearest neighbor statistics were applied to identify how community structure changes during S. macrophyllus encroachment. Results showed that phylogenetic distance, phylogenetic diversity, and mean phylogenetic distance increased when species diversity increased and the abundance of S. macrophyllus decreased in forest communities. Net related index values were positive, which indicates a clustered phylogenetic structure among all sampled forest communities. S. macrophyllus trees were mixed well with heterospecifics and had regular to aggregated distributions, whereas the species showed evidence of being a strong competitor with its neighbors. Competition could be a major ecological process regulating forest communities encroached by S. macrophyllus. According to the forest disturbance effects, phylogenetic community properties showed the loss of phylogenetic relatedness when S. macrophyllus increased in abundance. To our knowledge, S. macrophyllus encroaches tropical rain forest communities as a disturbance-adapted species.

中文翻译：

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大叶Streblus侵扰的热带雨林的系统发育群落和最近邻结构

尽管 热带森林生态系统中木本植物的入侵与改变的干扰机制有关，但对最近的邻域结构和群落系统发育的影响仍然知之甚少。大型Streblus macrophyllus在其生命的早期阶段是对光有需求的物种，并且作为成熟树具有耐荫性。越南北部热带喀斯特常绿森林中可发现大叶葡萄球菌。它经常在人为干扰的林分中以高密度再生。了解大叶链球菌入侵的扰动森林的结构模式在Cuc Phuong国家公园中，以不同的丰度水平建立了三个完整的1公顷土地。结合系统发生群落和最近邻统计数据的方法，可用于确定大叶链球菌入侵期间群落结构的变化。结果表明，在森林群落中，随着物种多样性的增加和大型链球菌的丰度降低，系统发生距离，系统发生多样性和平均系统发生距离增加。净相关指数值为正，表明所有采样森林群落中的聚类系统发育结构。大叶葡萄球菌树木与异种混合得很好，并且具有规则的至聚集的分布，而该树种则显示出与其邻国有很强的竞争性。竞争可能是调控被大叶。虫侵害的森林群落的主要生态过程。根据森林扰动的影响，当大叶链球菌大量增加时，系统发育群落特性显示出系统发育相关性的丧失。据我们所知，大叶沙棘（S. macrophyllus）作为适应干扰物种入侵热带雨林群落。