梯级水电开发对红水河鱼类群落功能多样性影响的研究

Cascade hydropower development is one of the most prominent factors affecting the river ecosystem and the functional diversity of fish communities. In this proposal, we will focus on the response mechanism of the fish community structure and functional diversity with environmental change in Hongshui River by combining traditional biodiversity assessment and functional diversity index. First, we will collect data on fish community composition and related environmental variables and analyse the effect of environmental variables on the spatial and temporal pattern of fish community and diversity. Fish community of Hongshui River will be divided into different functional groups based on functional traits which are related to feeding habits, habitat type, physiological tolerance and swimming ability. Besides, functional ecological approaches will be used to study the spatial-temporal pattern and dynamic changes of functional organization and diversity, and analyse the effect of environmental variables on the functional organization and diversity. At the same time, we will analyse the variation of fish community functional diversity before and after the cascade hydropower development, and clarify these major environmental factors that affect the functional diversity changes of the fish community of Hongshui River. Historical data of fish community and environmental factors will also be used to compare with the present data. If completed according to the experimental plan, our results will enrich the research methods of fish community ecology. In addition, it will be significant to the conservation, restoration and management of our country's fish biodiversity in the background of cascade hydropower development.

梯级水电开发是影响河流生态系统和鱼类群落功能多样性最突出的因素之一。本项目以红水河为研究区域，将功能多样性的研究方法与传统的生物多样性研究方法相结合，研究梯级水电开发背景下鱼类群落结构及功能多样性对环境变化的响应机制。首先，通过野外调查收集红水河鱼类群落分布和栖息地环境变量，分析栖息地环境变量对鱼类群落结构及多样性的时空格局的影响。而后采用功能生态学的研究方法，选取与食性类型、生境类型、生理耐受性和游泳能力等相关的鱼类功能特征参数，将鱼类划分成不同的功能群；研究鱼类功能群及功能多样性的时空格局和动态变化规律，分析栖息地条件对鱼类功能群和功能多样性的影响。同时结合历史数据资料，分析梯级水电开发前后鱼类群落功能多样性变化规律，厘清影响鱼类群落功能多样性变化的主要因子。本项目的完成将不仅丰富我国河流鱼类群落生态学的研究方法，而且对梯级水电开发背景下我国河流鱼类多样性保护、恢复和管理具有重要意义。

红水河是珠江流域西江水系的干流，被誉为水力资源的“富矿”，梯级水电开发对其流域经济具有巨大的推动作用，但是大坝的建设和运行给当地的生态环境、生物多样性，特别是鱼类资源带来较大的影响。本项目将功能多样性的研究方法与传统的生物多样性研究方法结合，研究了梯级水电开发背景下红水河鱼类群落结构及功能多样性，探讨鱼类功能性状空间格局及功能多样性对栖息地环境因子的响应规律。①通过野外调查和文献资料的收集，构建了红水河鱼类名录和鱼类生物学性状资料库；整理了红水河鱼类栖息地环境因子数据资料；研究了红水河鱼类群落结构的时空分布特征，分析了栖息地环境变量对鱼类群落分布的影响；②研究了红水河鱼类功能群的构成及分布特征，理清了栖息地环境条件对鱼类功能群的影响；并进一步分析了鱼类功能多样性的时空特征及其对环境条件变化的响应规律；③通过对比分析，厘清了红水河梯级开发前后鱼类群落功能多样性的变化规律，厘清了影响鱼类群落功能多样性变化的主要环境因素。梯级开发后，红水河干流的鱼类由早期的192种缩减到62种，以2018年的鱼类构成为基础，红水河干流鱼类鱼类平均分类差异指数（Δ+）为62.9，科多样性指数（F指数）为6.21，属多样性指数（G指数）为3.70，科属多样性指数（G-F指数）为0.40，与历史数据比较多样性指数呈下降趋势。鱼类的群落结构、功能群多样性及时空分布与大坝的建设参数、水库运行方式、水文情势等相关。本研究成果为流域梯级水电开发背景下鱼类生物多样性的保护、恢复和管理提供理论依据。