|CHEN Liangang,CHEN Liming,XU Yifan,JIA Jianwei,LUAN Zhenyu,SHI Yong,JIN Qiu,HU Tengfei.Ecological water level for proposed hydraulic construction locking Lake Poyang based upon wintering waterfowls habitat modelling. J. Lake Sci.2020,32(5):1519-1528. DOI:10.18307/2020.0523
|长江及鄱阳湖水系上游水库群运用后鄱阳湖枯季水文节律出现新的变化，为应对新的枯水情势，鄱阳湖水利枢纽作为一个选项被提出，如何确定其适宜的调控水位才能维持鄱阳湖湿地生态系统健康是其中的重点与难点.本文选择鹤类、小天鹅、鸿雁等食植物块茎水鸟作为鄱阳湖湿地生态系统的指示物种，基于EFDC水动力学模型和生境适宜度曲线构建了鄱阳湖越冬水鸟生境数值模拟模型；从食物资源与取食可及性两个方面，分苦草（Vallisneria natans）生长期和水鸟越冬期两个时段，以水深作为关键生境因子，对近10年鄱阳湖苦草及水鸟取食潜在生境面积变化进行了连续模拟；揭示了鄱阳湖苦草及水鸟取食潜在生境面积随水位的变化规律并构建了定量响应函数：苦草潜在生境面积随水位呈单峰型变化，在星子站水位为14.8 m时达到最大，约为1703 km2；越冬水鸟取食潜在生境面积随水位呈三段式变化，最大和最小面积分别约为564和476 km2，相应星子站水位分别为11.73和9.56 m.在此基础上，针对拟建的鄱阳湖水利枢纽工程，基于不同调度分期内生境保护目标的差异确定了符合天然水位波动特征的生态水位动态调控方案：下闸蓄水期内水位宜控制在16 m以下，后续根据越冬水鸟迁入情况逐步下降以增加取食生境面积，在12月-次年1月的越冬水鸟数量峰值期水位宜控制在12.5 m以下，后续根据来水情况逐步过渡至江湖连通期的自然状态.成果从保护越冬水鸟食物资源与取食可及性两个方面提出了鄱阳湖水利枢纽生态水位的动态调控阈值，为江湖新水沙条件下鄱阳湖湿地生态系统保育提供了量化依据.
|关键词: 湿地 越冬水鸟 沉水植被 生境模拟 生态需水 鄱阳湖
|Ecological water level for proposed hydraulic construction locking Lake Poyang based upon wintering waterfowls habitat modelling
CHEN Liangang1, CHEN Liming1, XU Yifan1, JIA Jianwei2, LUAN Zhenyu1, SHI Yong1, JIN Qiu1, HU Tengfei1
1.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, P. R. China;2.Bureau of Hydrology, Changjiang Water Resources Commission, Wuhan 430010, P. R. China
|After the operation of the reservoirs in the upper basins of the Yangtze River and Lake Poyang, the hydrological rhythm in dry seasons of the Lake Poyang has changed. In order to ease the pressure from low water level in dry seasons, a hydraulic construction locking the outlet of Lake Poyang was suggested. The key point of this project is to determine the suitable control schemes on water level which could maintain a healthy wetland ecosystem. Cranes, Cygnets and Swan Geese feeding with winter buds of Vallisneria natans were selected as the indicator of Lake Poyang ecosystem, a numerical habitat model for wintering waterfowls was developed by integrating an EFDC hydrodynamic model and habitat suitability curves. The water depth was adopted as the key habitat factor, the habitats for the wintering waterfowls feeding in dry seasons and V. natans in wet seasons have been continuously simulated since September in 2008. The variation laws between water level at Xingzi Station and the potential habitat area of V. natans and waterfowls feeding in Lake Poyang were revealed and the quantitative response functions were developed. The potential habitat area of V. natans gets the peak (around 1703 km2) when the water level reaches 14.8 m. The three-stage quantitative response functions between potential habitat area and water level have been developed for wintering waterfowls feeding, the maximum and minimum areas are about 564 and 476 km2, respectively, and the corresponding water levels at Xingzi Station are 11.73 and 9.56 m, respectively. For the proposed Lake Poyang hydraulic construction, a dynamic ecological water level control scheme as following is proposed: the water level should be controlled under 16 m during the refill period of Lake Poyang; then the water level would gradually decrease to increase the waterfowls feeding habitat areas; the maximum water level should be controlled below 12.5 m during December and January for the peak visiting of wintering waterfowls, and then gradually transits to natural state according to the inflow. The results could propose the ecological water control level for Lake Poyang hydraulic construction to protect the food resources and feeding accessibility of wintering waterfowls, and a quantitative basis for the conservation of Lake Poyang wetland ecosystem under new water-sand regime was provided.
|Key words: Wetlands wintering waterfowls submerged macrophyte habitat simulation ecological water demand Lake Poyang