Variation in different measures of diversity during primary succession on a tropical coastal dune

<b>Background</b>: The understanding of the processes that govern community assembly during ecological succession helps determine the ecological attributes in restoration and monitoring programmes. <b>Aims</b>: The aim of this long-term study of primary succession was to analyse changes in species richness, diversity, taxonomic distinctness and functional types to understand community assembly processes. <b>Methods</b>: For 25 years, species turnover was monitored in 150 permanent plots in a dune system on the coast of the Gulf of Mexico. <b>Results</b>: Earliest successional states had low species diversity and richness, a high unevenness in the taxonomic tree structure, and a lower number of functional groups, with psammophytes being dominant. Richness and diversity increased in a humped-back shape with intermediate states reaching the highest values. Succession generated taxonomic trees that became less uneven and more diverse, and the diversity of functional groups increased. <b>Conclusions</b>: The processes underlying community assembly are complex during succession: sand movement acts as an environmental filter affecting the dominant functional groups, and species interactions probably change from facilitation to competition. The understanding of the combined processes affecting the different measures of diversity over time can improve the effectiveness of restoration and conservation practice in dune systems.

**背景**：阐明调控生态演替过程中群落构建的机制，可为修复与监测项目中的生态属性确定提供理论支撑。**研究目标**：本项针对原生演替的长期研究旨在分析物种丰富度、多样性、分类学独特度以及功能群的变化规律，以揭示群落构建的内在机制。**研究方法**：研究团队在墨西哥湾沿岸的沙丘生态系统中，于150个永久样地内开展了长达25年的物种更替监测。**研究结果**：演替早期阶段的物种多样性与丰富度均较低，分类学树结构的不均匀性较高，功能群数量较少，且以沙生植物（psammophytes）为优势类群。物种丰富度与多样性呈驼峰型变化趋势，在演替中期达到峰值。随着演替推进，群落的分类学树结构不均匀性降低、多样性提升，功能群的多样性亦随之增加。**研究结论**：演替过程中的群落构建机制较为复杂：沙粒运动作为环境过滤因子影响着优势功能群的组成，物种间的相互作用可能由促进作用转向竞争作用。明晰随时间变化的多维度多样性调控机制，可提升沙丘生态系统修复与保护实践的成效。