大宁河水生态系统问题诊断及其分析

Diagnosis of water ecosystem problems and analysis in Daning River

摸清生态本底是复苏河湖生态环境的重要基础。本研究以长江一级支流大宁河巫溪段为研究区域,通过资料收集、文献调研、现场踏勘进行生态本底调查,以流量过程变异程度、底质曲率系数、鱼类Shannon多样性指数、鱼个体生态学指数等作为评价指标,从水文、水质、地貌、生物4个方面对研究区域水生态现状进行问题诊断及评估,从而针对存在问题提出相应对策。结果表明,水文情势变化趋于均匀化、水文变化过程偏离天然状态、汛期生态流量满足程度有待提高,水质状况整体良好,地貌单元多样性较好、河床底质偏离天然状态;鱼类种类数、多样性均有所下降,鱼类生态类型发生变化。基于存在的问题,提出了生态调度、栖息地修复与改善、增殖放流等对策,从而为受损河流的生态修复提供理论支撑。

Mapping the ecological background is an important foundation for recovering the ecological environment of river and lakes.This study takes the Wuxi section of the Daning River,a first-class tributary of the Yangtze River,as the study area,and investigates the ecological background through data collection,literature research,and field survey,and evaluates the current state of water ecology in the study area in terms of hydrology,water quality,geomorphology,and biology by using the variability of flow process,substrate curvature coefficient,fish individual ecological indices,and fish Shannon diversity index as evaluation indexes,so as to propose corresponding countermeasures for the existing problems.The results show that the hydrological situation tends to be homogeneous,the hydrological process deviates from the natural state,and the ecological flow in flood season needs to be improved,the overall water quality is good,the diversity of geomorphic units is good,and the riverbed substrate deviates from the natural state;the number and diversity of fish species have decreased,and changes in fish ecotypes.Based on the existing problems,countermeasures such as ecological scheduling,habitat restoration and improvement,and stocking and releasing are proposed,thus providing theoretical support for ecological restoration of damaged rivers.