基于种内性状分化的三峡水库消落带植物群落功能多样性维持机制

Research on the function and dynamic of the plant community under the specific circumstances of dam regulation and water management, has arrtacted much attention in addressing impacts of hydropower-complex projects on environment. Plant community consist of a bunch of plants with same or different functional trait. Environment changes the community structure by changing intraspecific trait variation (ITV) and species turnover. Water-level-fluctuating zone (WLFZ) of Three Gorges Reservoir has simple plant community structure impacted by water level fluctuation. Intraspecific trait variation counts more with limiting species turnover in functional diversity research. In this project, functional diversity maintaining will be studied in an intraspecific trait variation perspective. Field trait investigation will be conducted to assess the distribution pattern of ITV and functional diversity in WLFZ. The contribution of ITV in functional diversity and its response to the water level fluctuating will be studied to elucidate the mechanism to maintain community functional diversity. The project will therefore greatly assist in the restoration and management of riparian ecosystems of the Three Gorges Reservoir.

消落区植被在水位调节下的群落功能及动态响应，是研究水利枢纽工程对流域生态环境影响的热点。植物群落由具有相同或不同功能性状的多个物种组成。环境通过选择或过滤作用改变群落种内性状分化和物种周转，影响群落结构进而影响群落功能。受强烈水位波动影响的三峡水库消落带，植物群落结构简单。有限的物种周转下，对功能多样性的研究中，种内性状分化研究至关重要。本研究从种内性状分化入手，通过消落带种内性状分化和功能多样性分布格局，结合群落种内性状分化在功能多样性中的贡献及其对水淹、出露干扰过程的响应，解释水位脉动条件下植物群落功能多样性的维持机制，为消落带生态修复和生态系统管理提供科学依据。

消落区植被在水位调节下的群落结构及动态响应，是研究水利枢纽工程对流域生态环境影响的热点。受强烈水位波动影响的三峡水库消落带，植物群落结构简单。本研究从植物性状入手，研究了消落带植物群落对周期性异质水文条件的响应。通过原位布点样方，监测了消落带植物群落多样性时空分布、主要物种性状时空分异及群落结构对异质水文条件的关系。主要获得以下结果:(1) 消落区植物面对消落带的水淹干旱交替，包括苍耳和狗牙根在内的物种采取不同的策略。狗牙根与其他植物相比，具有明显保守的生长曲线，藿香蓟变异最广，空心莲子草次之。（2）对于消落区植物群落构建，水淹时间和水淹深度只占了一部分作用，而且不同季节呈现不同的关系，但总体而言，水淹深度都比水淹时间有更好的指示作用。（3）相比于其他植物对于消落区泥沙沉积的低存活率，较高的耐受性使狗牙根更倾向于受益于泥沙沉积，从而保持并增加狗牙根在消落区的优势度。本研究从植物群落对异质水文条件的响应方面，解释了消落带植物群落构建机制，为消落带生态修复和生态系统管理提供科学依据。