中文摘要：

为研究拆坝对河流生态系统造成的影响,从短期和长期两个时间尺度综合分析了河流水文情势、地形地貌、岸边带植物、鱼类和底栖动物等关键生态因子对拆坝的响应,并总结了目前拆坝对生态系统影响的两种主要评估方法。认为根据实际拆坝情况进行评估和基于数值模型进行预测两种评估方法中,实地观测是最直接、最有说服力的研究方法,但受成本和一些不可控因素限制;数值模拟具有速度快、费用低、无比尺影响等优点,可对拆坝影响进行预测,为管理者提供参考,但精度和准确性有待提高。指出后续研究中应综合考虑拆坝过程中各生态因子间的耦合效应,需对不同拆坝时机和分阶段拆坝方式对河流生态系统的影响进行深入研究。

英文摘要：

To study the impacts of dam removal on river ecosystems,the response of key ecological components,such as river hydrological conditions,topography,riparian plants,fish,and zoobenthos,to dam removal are analyzed from both the short-term and long-term perspectives.Two currently used major assessment methods are summarized,including assessment of actual removal conditions and numerical modeling forecasting.Field surveying is considered the most direct and convincing research tool,but it is limited by cost and other uncontrollable factors.Numerical simulation has remarkable advantages,such as high speed,low cost,and freedom from scale effects,and can forecast the influence of dam removal and provide decision references for managers.However,the precision and accuracy of simulation need to be improved.It is pointed out that further studies should comprehensively consider the coupling effects among various ecological factors in the process of dam demolition,and the impacts of different demolition times and dam removal phases on river ecosystems require deeper examination in the future.