三峡水库补水调度对东洞庭湖典型沉水植物生境适宜性的影响

沉水植物是东洞庭湖水生态修复的重要物种，水深是影响沉水植物生长的关键因子之一。为定量描述三峡水库不同补水调度方式对东洞庭湖典型沉水植物生长生境的影响，以刺苦草（Vallisneria spinulosa）为目标物种，利用物理栖息地模型建立三峡水库补水调度期间不同出库流量与东洞庭湖刺苦草生长生境加权可利用面积（WUA）的关系。结果表明：刺苦草生长生境的适宜水深为0.2~1.8 m，最适宜水深为0.5~1.0 m；三峡水库实施补水调度后，东洞庭湖刺苦草生长生境的WUA整体呈现均匀上升趋势；三峡水库补水调度期间，出库流量为5 500~10 500 m³/s时，刺苦草生长生境最适宜水深范围对应的WUA呈现先增后减趋势，在出库流量为9 500 m³/s时WUA最大（74.46 km²），可认为刺苦草生长最适宜出库流量为8 500~10 500 m³/s。研究成果可为通过三峡水库生态调度进行东洞庭湖水生态环境恢复及保护提供参考。

Impact of Three Gorges Reservoir water supply regulation on habitat suitability of typical submerged plants in East Dongting Lake

Submerged plants are important species for ecological restoration of water in East Dongting Lake, and water depth is one of the key hydrodynamic factors affecting the growth of submerged plants. In order to quantitatively describe the impact of different water supply modes of the Three Gorges Reservoir (TGR) on typical submerged plants growth habitat in East Dongting Lake, taking Vallisneria spinulosa as the target species, the relationship between different outflow from TGR and the weighted usable area (WUA) of Vallisneria spinulosa growth habitat in East Dongting Lake during TGR water supply operation was established by using physical habitat simulation model (PHABSIM). The results showed that the suitable water depth range for the growth habitat of Vallisneria spinulosa was 0.2~1.8 m, the optimal water depth range was 0.5~1.0 m. After TGR implementing the water supply operation, WUA of Vallisneria spinulosa growth habitat in East Dongting Lake showed a uniform upward trend totally. During the period of TGR water supply, the outflow was 5 500~10 500 m3/s. With the increase of the outflow of TGR, WUA corresponding to the optimal water depth range for Vallisneria spinulosa growth habitat firstly increased and then decreased. When the outflow range was 9 500 m3/s, the maximum WUA was 74.46 km2. It could be considered that the optimal outflow range of Vallisneria spinulosa was 8 500~10 500 m3/s. The results were expected to provide reference for restoring and protecting the water ecological environment in East Dongting Lake through TGR ecological scheduling.