The expansion of hydropower in combination with the already existing infrastructure and a changing climate are significantly influencing the world's rivers. The resulting alteration in flow regimes is expected to strongly affect fish habitat and associated fish communities both spatially and temporally. Using habitat modelling, this study identified habitat bottlenecks during the critical summer low flow period and fish assemblages that will be most susceptible to regulated and predicted future flow regimes in the Saint John River downstream the Mactaquac Generating Station. Expert knowledge-based habitat models were applied at the meso-scale to evaluate the influence of alternative future flow regimes on habitat suitability indices of fish assemblages. Dam renewal and removal scenarios predicted low habitat suitability for rheophilic fish species, particularly during prolonged low flow periods in dry years. Limnophilic and eurytopic fish assemblages were not expected to be limited in habitat conditions. Overall, the proposed modelling approach represents a promising tool to support the development of environmental flows in large regulated rivers that face challenges with ageing infrastructure and a changing climate.

中文翻译：

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气候变化下大型调节河流鱼类栖息地的定量建模

水电的扩张与现有的基础设施和不断变化的气候相结合，正在对世界河流产生重大影响。由此产生的流态变化预计将在空间和时间上强烈影响鱼类栖息地和相关鱼类群落。使用栖息地建模，本研究确定了关键的夏季低流量期间的栖息地瓶颈，以及最容易受到 Mactaquac 发电站下游圣约翰河中受监管和预测的未来流态影响的鱼类群落。以专家知识为基础的栖息地模型在中尺度上应用，以评估替代未来流态对鱼类群落栖息地适宜性指数的影响。大坝更新和拆除情景预测，对于嗜流性鱼类物种的栖息地适宜性较低，特别是在干旱年份的长时间低流量期间。Limnophilic 和 eurytopic 鱼类组合预计不会在栖息地条件下受到限制。总体而言，所提出的建模方法代表了一种有前途的工具，可以支持大型受监管河流中环境流量的发展，这些河流面临着基础设施老化和气候变化的挑战。