长江中游典型河段底栖动物的物理栖息地模型构建与应用

考虑水生生物生境需求的物理栖息地模型被认为是评估河流流量变化对水生态系统影响的最可信的方法之一。本研究选取长江干流含有河漫滩的监利江段为实例,建立底栖动物各类群的物理栖息地模型,计算变化流量下栖息地适宜面积的时间序列,并据此进行生态流量决策。结果显示长江中游底栖动物最敏感的环境参数是流速,适宜范围为0～0.2 m/s;其次是水深,适宜范围为0～6 m。在考虑敏感环境参数的前提下,得出监利江段底栖动物的最佳生态流量为20 000 m3/s。三峡大坝蓄水后枯水期和平水期底栖动物适宜面积的低值部分减小,丰水期适宜面积增加。为了保护底栖动物栖息地,建议三峡大坝在防洪蓄水的同时能兼顾底栖动物的生态流量需求,调节枯水期和平水期的流量,让监利江段接近4000 m3/s,丰水期接近20 000 m3/s。在枯水年增大枯水期和平水期的流量,平水年增大枯水期的流量,丰水年减少丰水期的流量。本研究方法可以供长江其他河段目标物种的生态流量决策和生态修复方案设计参考。

Applying physical habitat model of zoobenthos in typical reaches of the Yangtze River

The physical habitat model considering the habitat demand of aquatic organisms is considered to be one of the most popular method to evaluate the impact of the flow change on river ecosystem. In this study,the Jianli river section of the main stream of the Yangtze River with islands and floodplain is selected as an example to establish the physical habitat model for different macrozoobenthos groups, calculate the time series of the suitable habitat area under the changing flow to make the ecological flow decision accordingly. The results show that the most sensitive environmental parameter of macrozoobenthos is velocity, and the suitable range is 0~0.2 m/s. The second is water depth, and the suitable range is 0~6 m. Considering the sensitive environmental parameters, the best ecological flow of macrozoobenthos is 20 000 m 3/s in wet period and 4000 m³/s in dry period. After impounding the Three Gorges dam,the low value of weighted usable area in dry period and normal period decreases,while increases in wet period. In order to protect the habitat of benthic animals,it is suggested that the Three gorges dam can take into account the ecological flow demand of benthic animals while flood control and water storage, increase the flow in the dry period and the normal period in the dry year,increase the flow in the dry period in the normal year, and reduce the flow in the wet period in the wet year. The results of this study can be used as a reference for the ecological flow decision-making and ecological restoration scheme design of different target species in other reaches of the Yangtze River.