高寒灌木关键功能性状与地理环境相互作用研究

Alpine shrubs are an important component of the alpine vegetation, with special functional traits and superficial characteristics of environmental adaptation, and exploring the relationship between their key functional traits and distributional environment is a prerequisite for maintaining shrub stability and preventing expansion to meadow steppe. In this project, through localized observation and investigate analysis on the elevational gradient transect in the Northern Zoige Plateau, to carry out the study on the interspecific functional traits differences and the carbon assimilation capacity of the alpine evergreen and deciduous shrubs, variation and trade-off relationship of functional traits in the same shrub species with elevational gradient. Screen reflects the leaf maximized carbon capture and minimized carbon consumption, i.e. the maximum net carbon assimilation of leaf carbon economy key functional traits, and to analyze the relationship between key functional traits and other traits. Combine with the analysis of micro topoclimate and soil water-thermal characteristic, and the investigation of distribution characteristics of alpine shrubs, the meta-analysis of interactions between key functional traits and distribution habitats of alpine shrubs was conducted. Understand the characteristics of carbon balance of alpine shrubs and their corresponding environmental conditions, and to explore the relationship between specific leaf area, specific leaf volume and leaf temperature regulation, photosynthetic capacity, and habitats, and to reveal the changes in key functional traits of alpine shrubs and the physiological and ecological regulation mechanism of the leaf carbon economy formation under alpine environmental gradients. In practice, the results will provide important information and theoretical basis for grazing and human intervention to maintain alpine vegetation stability and prevent shrub invasion.

高寒灌木是高寒植被的重要组成部分，具有特殊功能性状与环境适应表征，探究其关键功能性状与分布环境的关系是维护灌木稳定和防止向草甸草原扩张的必要前提。本项目在若尔盖高原北部布设的垂直样带基础上，通过定位观测和调查分析，开展高寒常绿和落叶灌木种间功能性状差异和碳同化能力比较，同种灌木随海拔梯度功能性状变异与权衡关系分析；筛选反映叶片最大化碳获取和最小化碳消耗，即最大净碳同化量的叶碳经济关键功能性状，分析关键功能性状与其他性状之间的关系；结合气候和土壤水热特征分析，以及高寒灌丛分布特征调查，进行高寒灌木关键功能性状与分布生境相互作用的整合分析。认识高寒灌木碳平衡的表征性状及相应环境条件，探讨比叶面积、比叶体积与叶温调节、光合能力和生境的关系，揭示高寒环境梯度下高寒灌木关键功能性状变化及叶碳经济形成的生理和生态调控机制；为放牧和人为干预维护高寒植被稳定和防止灌木入侵草地等提供重要资料和理论依据。

高寒灌木是高寒植被的重要组成部分，具有特殊功能性状与环境适应表征，探究其关键功能性状与分布环境的关系是维护灌木稳定和防止向草甸草原扩张的必要前提。本项目依据常绿和落叶灌木地理分布格局，通过布置的灌木观测重点样地和功能性状观测试验，结合气候和土壤水热特征分析，对高寒灌木关键功能性状与分布生境土壤和气候相互作用进行了整合分析。研究结果发现比叶面积和比叶体积与灌木扩张强度紧密关联，而气候因子(最暖季的平均温度)是影响灌木比叶面积与比叶体积的重要因素；基于不同海拔高度收集的植物多样性和土壤理化性质数据，通过测量植物群落相似性随空间、环境变量的变化，发现在高寒草甸植被群落构建中，环境过滤比扩散限制更重要，且增温可能改变高寒植物群落结构组装。结合在若尔盖高原北部布设的长期增温原位试验平台，以高寒草甸典型植物为研究对象，发现未来气候变暖会改变高寒草甸群落物种组成，直根系的双子叶植物比须根系的单子叶植物具有更强的适应性，即优良牧草受限，毒杂草扩张；通过分析不同水分梯度下高寒草甸植物地下芽库分布与地上群落特征，发现高寒草甸草毡层含水量影响芽库的分布、大小及组成，是影响高寒草甸群落稳定性的主导生态因子。通过比较高寒草甸植物地下芽库沿海拔梯度的分布特征，发现海拔高度是影响高寒草甸群落生产力的重要因素。以上研究结果表明，在未来全球气候变暖条件下，灌木扩张趋势将进一步增加。比叶体积功能性状指标与灌木生物量和丰度的联系最紧密，防控草原灌木扩张的管理措施应充分考虑不同因素的差异影响。