水电开发干扰下底栖动物功能性状结构及群落构建机制研究

Hydropower development has dramatically altered the water environmental conditions of most rivers in China, affecting the survival of aquatic organisms, and threatening the health of aquatic ecosystems. Macroinvertebrates are key component in river systems and play an important role in maintaining the balance and health of aquatic ecosystems. However, previous studies have focused largely on the taxonomic diversity changes of macroinvertebrates after the dam construction, the functional trait structure and the mechanism of macroinvertebrate community assembly and reconstruction have not been systematically studied. In this project, we selected the adjacent Buyuan river (undammed) and Nanla river (dammed), the two first order tributaries in the lower reaches of Lancang river, as research areas, to reveal the effect of dam on macroinvertebrate trait structure and underlying driving factors through comparing the changes of functional traits in undammed and dammed river, as well as reference and disturbance reach in dammed river. Then combined with the traits - environmental/spatial relationship, to reveal the driving factor of traits structure change and the relative role of multiple ecological processes, such as deterministic and stochastic processes, in the macroinvertebrate community assembly after hydropower development. The outputs of this project will help us deeply understand the relationship between disturbance of hydropower development and macroinvertebrate community reassembly, and provide scientific basis for the restoration and protection of aquatic habitats in dammed rivers and further the protection of river ecosystems in southwest China.

水电开发已显著改变我国大部分河流的水环境条件，影响了水生生物的生存繁衍，威胁到水生生态系统健康。底栖动物是河流生态系统的关键组成部分，在维系水生生态系统的平衡和健康中起着重要作用。以往的研究多关注建坝后底栖动物物种多样性的变化，而对底栖动物功能性状结构及群落构建\重建的机制还缺乏系统研究。本项目拟以澜沧江下游相邻的两条一级支流—南腊河(建坝)和补远江(未建坝)为研究区域，通过比较建坝河流与未建坝河流，以及建坝河流受影响河段和参照河段底栖动物功能性状的差异，结合功能性状-环境/空间关系及其变化，探索水电开发对底栖动物功能性状结构的影响规律和驱动因素，揭示不同生态学过程(确定性过程和随机性过程)在水电开发后底栖动物群落构建中的作用机制。研究结果有助于阐明建坝干扰与底栖动物群落重建之间的关系，为筑坝河流水生生物栖息地修复及保护，以及我国西南诸河水生生态系统保护提供科学依据。

水电开发已显著改变我国大部分河流的水环境条件，影响了水生生物的生存繁衍，威胁到水生生态系统健康。以往的研究多关注建坝后底栖动物物种多样性的变化，而对底栖动物功能性状结构及群落构建\重建的机制还缺乏系统研究。本研究以澜沧江下游相邻的两条一级支流—南腊河(建坝)和补远江(未建坝)为研究区域，比较了建坝河流与未建坝河流，以及建坝河流受影响河段和参照河段底栖动物功能性状的差异，结合功能性状-环境/空间关系及其变化，探索水电开发对底栖动物功能性状结构的影响规律和驱动因素，揭示不同生态学过程(确定性过程和随机性过程)在水电开发后底栖动物群落构建中的作用机制。主要取得以下重要结果：（1）建坝显著影响了河流底栖动物的功能性状结构，67%的性状类别（主要为个体大小、化性、产卵位置、成虫生活周期、生活习性、漂流性、功能摄食类群以及防御能力）会受到建坝的显著影响，坝下功能性状的变化会影响到整个河流性状结构；（2）建坝河流的物种和功能β多样性均高于未建坝河流；物种/性状替代是β多样性的主要组分，且在建坝河流中高于未建坝河流；环境过滤是β多样性及其替代组分的主要驱动力，而丰富度差异主要由空间因素驱动。空间变量在南腊河的作用大于补远江，表明建坝影响了底栖动物群落聚合的空间过程。本研究结果有助于阐明建坝干扰与底栖动物群落重建之间的关系，为筑坝河流水生生物栖息地修复及保护，以及我国西南诸河水生生态系统保护提供科学依据。