Meng Weiqi, Zhang Haonan, Sun Lianhao, Xu Jianing, Qiao Yajun, Li Haidong
Innovative Research Team for Forest Restoration Mechanisms, Chishui National Ecological Quality Comprehensive Monitoring Stations, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment (MEE), Nanjing 210042, China.
Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, Nanjing 210037, China.
Plants (Basel). 2025 Jul 8;14(14):2098. doi: 10.3390/plants14142098.
This study focuses on a subtropical evergreen broad-leaved forest in China, utilizing a large permanent plot established in the Yaoluoping National Nature Reserve. By integrating data from a full-stem census and total station surveying, we analyzed the phylogenetic structure of the plant community as a whole and across different life-history stages (saplings, juveniles, and adults) while quantitatively assessing microtopographic variables and an interspecific competition index. The results indicate that the overall community in the Yaoluoping plot exhibited a weakly overdispersed pattern, and key microtopographic factors-including aspect, terrain position index (TPI), terrain ruggedness index (TRI), roughness, and flow direction-significantly influenced the evolution of phylogenetic structure. Distinctions were also observed among saplings, juveniles, and adults in phylogenetic structuring across life-history stages. Specifically, saplings displayed a higher degree of phylogenetic clustering, significantly influenced by density, elevation, TPI, and flow direction-suggesting that environmental filtering predominates at this stage, possibly due to lower environmental tolerance, limited dispersal ability, and conspecific negative density dependence. In contrast, juveniles and adults showed a more dispersed phylogenetic structure, with density, interspecific competition, aspect, TRI, TPI, and roughness significantly correlated with phylogenetic patterns, indicating that competition and niche differentiation become increasingly important as trees mature and establish within the community. Interspecific competition was found to play a crucial role in community structuring: the competition index was generally negatively correlated with the net relatedness index (NRI) and nearest taxon index (NTI) in juveniles and adults, implying that intense competition leads to the exclusion of some species and reduces overall diversity, with the strength and significance of competitive effects differing across stages. This study enhances our understanding of the complex interplay between microtopography and interspecific competition in shaping the phylogenetic structure and diversity of subtropical evergreen broad-leaved forests, elucidates the coupled mechanisms among microtopography, phylogenetic structure, and competition, and provides a scientific basis for forest conservation and management.
本研究聚焦于中国的一片亚热带常绿阔叶林，利用在鹞落坪国家级自然保护区设立的大型永久性样地。通过整合全树普查和全站仪测量的数据，我们分析了整个植物群落以及不同生活史阶段（幼树、幼苗和成年树）的系统发育结构，同时定量评估了微地形变量和种间竞争指数。结果表明，鹞落坪样地的整个群落呈现出弱过分散模式，关键微地形因素——包括坡向、地形位置指数（TPI）、地形崎岖度指数（TRI）、粗糙度和水流方向——显著影响系统发育结构的演变。在不同生活史阶段的系统发育结构中，幼树、幼苗和成年树之间也存在差异。具体而言，幼树表现出更高程度的系统发育聚类，受密度、海拔、TPI和水流方向的显著影响——这表明在此阶段环境过滤起主导作用，可能是由于较低的环境耐受性、有限的扩散能力和同种负密度依赖。相比之下，幼苗和成年树表现出更分散的系统发育结构，密度、种间竞争、坡向、TRI、TPI和粗糙度与系统发育模式显著相关，表明随着树木在群落中成熟和定居，竞争和生态位分化变得越来越重要。发现种间竞争在群落结构中起关键作用：在幼苗和成年树中，竞争指数通常与净亲缘关系指数（NRI）和最近类群指数（NTI）呈负相关，这意味着激烈的竞争导致一些物种被排除并降低了总体多样性，竞争效应的强度和显著性在不同阶段有所不同。本研究增进了我们对微地形和种间竞争在塑造亚热带常绿阔叶林系统发育结构和多样性方面复杂相互作用的理解，阐明了微地形、系统发育结构和竞争之间的耦合机制，并为森林保护和管理提供了科学依据。
