中亚热带石灰岩常绿落叶阔叶混交林植物功能性状分异及其对环境变化响应的研究

The mid-subtropical zonal limestone forest vegetation is one kind of special forest ecosystems, and its climax community is a mid-subtropical evergreen and deciduous broad-leaved mixed forest. This vegetation type has a unique biodiversity and special environment and trees in it are sensitive to changing environment, which may be a unique ways adjusting to environment. Besides, functional traits play main role in trees reponse to changing environment, therefore, are considered as the effective tool to indicate changing environment. In this project, major mid-subtropical evergreen and deciduous broad-leaved mixed forests will be selected at different areas (North-east, North, North-west and central) of Guangxi Zhuang Autonomous Region with environmental gradients (e.g. precipitation, temperature and soil factors). We will measture key functional traits of each individual trees, establish species level phylogenetic tree and sample different scales environmental factors. On this basis, variations of plant functional traits will be analyzed across different scales organizational levels (e.g. intraspecies, interspecies and community level), spatial and heterogeneous environmental conditions using a method of hierarchical variance partition in the mid-subtropical evergreen and deciduous broad-leaved mixed forest. And then, we will performed a general linear mixed model to test how the phylogeny and environments on variation in functional traits in it. More, we will analyze how environments at different scales impacted on funcational traits by removing phyloggenetic effects using a PIC (phylogenetically independent contrasts) method. Meanwhile, we will examine the impacts of different envionments on functional traits using a partial Mantel test, and assess the mechanism of trees response to changing environment in it. This study is able to contribute to grasp the rules for limestone forest plants to adapt environment and provide sound theoretical foundation to select the appropriate target tree species for afforestation in karst stone mountains.

中亚热带地带性石灰岩森林植被是一种特殊的森林生态系统，顶级群落为常绿落叶阔叶混交林，由于其生态环境特殊，存在着特有生物多样性和生态现象；同时，植物对环境变化敏感，因而可能存在特殊的适应环境方式。植物功能性状反映植物对环境变化的响应，是指示环境改变的有效工具。本项目以中亚热带石灰岩常绿落叶阔叶混交林为研究对象，通过个体水平上功能性状测定、物种水平系统发育树构建和不同尺度环境因子取样，研究中亚热带石灰岩常绿落叶阔叶混交林植物功能性状在种内、种间和群落水平的性状分异规律，探讨其随个体大小、空间尺度和环境异质性的变化规律，揭示环境和系统发育对功能性状分异特征的相对影响；然后排除系统发育因素，探索环境因子对功能性状的影响规律，阐明中亚热带石灰岩常绿落叶阔叶混交林对环境变化的响应机制。项目成果有助于掌握石灰岩森林植物对环境的适应规律，为岩溶石山植被恢复选择适合树种和构建稳定的群落结构提供理论依据。

本项目针对中亚热带石灰岩地带性植被常绿落叶阔叶混交林是一种特殊的森林生态系统，考虑岩溶石山特殊生境的特点，植物对环境变化敏感，功能性状分布特征是对环境变化的响应。从不同组织水平（种内、种间和群落），不同空间尺度（5m×5m、10m×10m、20m×20m、50m×50m、100m×100m）和不同分类水平（科、属和种）角度进行性状分布规律的分析；在此基础上，继续对性状分异对环境变化响应规律的探索和除开系统发育，揭示出环境因子对功能性状的影响程度。结果发现：①石灰岩常绿落叶阔叶混交林群落的功能性状在科、属、种分类尺度和不同组织水平（种内，种间，群落）的频度分布多为长尾分布；大部分植物功能性状变异主要来自种间，但种内变异也是功能性状变异的重要来源且不容忽视。②植物功能性状的空间变异性主要体现在小尺度范围内(5m×5m)，而环境因子的空间变异规律与之正好相反，在5m×5m尺度上空间变异最小，且环境因子对功能性状的影响具有尺度效应。③影响植物功能性状变异的主要环境因子包括土壤水溶性钙、有机质、全氮、全磷、土壤水分含量和海拔高度。④进化历史对石灰岩常绿落叶阔叶混交林群落的影响强度不高；⑤生态位机制是解释石灰岩常绿落叶阔叶混交林群落组配机制的最佳理论。本项目在野外共建立6hm2样地，已经发表文章10篇，其中sci论文4篇，3篇sci论文影响因子大于3.0。培养研究生7名，其中5名已毕业。项目成果有助于掌握石灰岩森林植物对环境的适应规律，为岩溶石山植被恢复选择适合树种和构建稳定的群落结构提供理论依据。