Intraspecific variation and economics spectrum of Phragmites australis in lakeshore wetland of (semi-) arid regions

<em>Phragmites australis</em>, as a widely distributed species, has a high degree of intraspecific variation in functional traits and is able to respond to external climatic and environmental changes and adjust its adaptation strategies on time. The plant economic spectrum can reflect the adaptation strategies of resource acquisition and storage of plants in different climatic regions, and provide a scientific basis for understanding the ecological differentiation of plants in different habitats and their adaptation mechanisms. In this study, the morphological traits, nutrient contents and stoichiometric ratios of <em>P. australis</em> in lakes and lakeshore wetlands of semi-arid and arid climatic regions from east to west in Inner Mongolia Plateau were investigated to reveal the variability of plant functional traits at different regional scales and the influencing factors, and to reveal the ecological adaptation strategies of <em>P. australis</em> in different regions through plant economic spectrum. The results showed that soil moisture gradient, geographic location and regional scale effected the intraspecific variation of functional traits of <em>P. australis</em>. At the local scale, soil moisture gradients had opposite effects on the response to functional traits of <em>P. australis</em> in the arid and semi-arid regions. At the regional scale, climatic factors dominated the variation of reed functional traits across the latitudinal gradient, while the correlation with soil properties was not significant (<em>P</em> &gt; 0.05). Plant economic spectrum theory is also applicable to the functional traits of various organs and whole plants of <em>P. australis</em> populations at different regional scales, and the acquisition and assimilation of resources is conservative in arid regions, while in semi-arid regions it is an acquisition strategy. This study provides a new understanding of the ecological niche differentiation and drivers of plant populations and ecological adaptation strategies of species at the regional scale, and provides a theoretical basis for the restoration and reconstruction of degraded wetland ecosystems.芦苇（Phragmites australis）作为广布物种，其功能性状存在高度的种内变异，可响应外界气候与环境变化并及时调整适应策略。植物经济谱（plant economic spectrum）能够反映不同气候区域内植物的资源获取与储存适应策略，为解析不同生境下植物的生态分化及其适应机制提供科学依据。本研究针对内蒙古高原自东向西的半干旱与干旱气候区的湖泊及湖滨湿地中的芦苇开展调查，测定其形态性状、养分含量及化学计量比，旨在阐明不同区域尺度下植物功能性状的变异特征及其影响因子，并通过植物经济谱揭示芦苇在不同区域的生态适应策略。结果表明，土壤水分梯度、地理位置与区域尺度均对芦苇功能性状的种内变异存在显著影响。在局域尺度下，土壤水分梯度对干旱与半干旱区芦苇功能性状的调控效应存在截然相反的方向。在区域尺度上，气候因子主导了沿纬度梯度分布的芦苇功能性状变异，而其与土壤属性的相关性并不显著（P > 0.05）。植物经济谱理论同样适用于不同区域尺度下芦苇种群各器官及整株的功能性状；干旱区芦苇的资源获取与同化策略趋于保守，而半干旱区则偏向资源获取型策略。本研究为解析植物种群的生态位分化及其驱动因子、区域尺度下物种的生态适应策略提供了全新认知，同时为退化湿地生态系统的修复与重建提供了理论依据。