基于湖沼湿地底栖动物生境适宜性响应的水文连通性阈值研究

如何从水动力-水质-水生态耦合系统整体角度分析湖沼湿地水文连通性变化的生态环境效应，进而通过调控水文连通性来改善生态系统稳定性是湿地生态修复的重要途径。本项目以白洋淀湖沼湿地为典型研究区，选取可较好地指示水质状况、对外界干扰较敏感的底栖动物为指示物种，分别基于GIS、InSAR技术从宏观和微观尺度研究1990年来湿地水文连通性的时空变化规律，并结合历史资料分析辨识受连通性变化影响显著的底栖动物生境因子；通过不同水文连通梯度下野外实验监测分析，探究水文连通性变化下水动力、水质、沉积物要素生境因子和底栖动物群落的联动响应，揭示底栖动物生境适宜性对水文连通性变化的响应机理；运用水动力-水质耦合模型和生境适宜性模型模拟底栖动物适宜生境面积指数对水文连通性指数变化的响应，阐明不确定性系统中基于底栖动物生境适宜性响应的水文连通性阈值区间及其时空、等级差异，为湿地水文连通格局优化和生态修复提供科技支持。

It is vital to analyze the eco-environmental effects caused by the changes in hydrological connectivity in lacustrine wetlands, especially from the perspective of hydrodynamics-water quality-hydroecology as a whole system. Thus, alleviating the water environmental stress by regulating the hydrological connectivity has become a key approach of ecological restoration for wetlands. In this research, a typical lacustrine wetland, Baiyangdian wetland, is taken as the study area, where benthic animals, which can well indicate water quality and are sensitive to external disturbances, are selected as indicator species. Firstly, using GIS technology and InSAR technology, the temporal and spatial variations of hydrological connectivity of the wetland since 1990 are revealed at both macro and micro scales; and combining with historical data analysis, the benthic habitat factors that responded significantly to changes in connectivity are identified. Secondly, with field experiments conducted under different hydrological connectivity gradients, the linkage reactions of benthic habitat factors with respect to hydrodynamics, water quality and sediment elements and benthic animal community to the changed hydrological connectivity are investigated, to reveal the response laws of the benthic habitat suitability to hydrological connectivity. Thirdly, a hydrodynamic-water quality model is coupled with a habitat suitability model to simulate the correlation between the habitat suitability area index and hydrological connectivity index; and aiming at the uncertain of the ecosystem, the ranges of the hydrological connectivity thresholds with spatiotemporal grade differences of wetlands are then proposed based on the corresponding responses of the benthic habitat suitability. This research can provide scientific references for wetland restoration planning under the influences of climate change and human activities.