Multiyear drought is projected to increase in frequency and duration in arid and semiarid regions across the world, threatening native species and ecosystem function. The effects of multiyear drought are often exacerbated by human water use, which manifest in reduced lake elevation, reduced stream discharge, and disruption in hydrologic connectivity for aquatic species. Here, we demonstrate that drought‐driven decreasing lake levels reduce the connectivity between tributaries and lakes by creating an elevation‐explicit tributary distance map. We combined long‐term fish catch data and a lake elevation time‐series with our elevation‐explicit tributary distance map to test whether population demographics are related to drought‐driven changes in tributary connectivity. We surveyed the littoral zone of Bear Lake, Utah and Idaho, USA, from full pool to a depth of >12 m, totalling 94.86 km² surveyed. As lake elevation decreased from full pool to the lowest historical elevation, tributary channel distance increased by 3.5 km. Bear Lake Bonneville Cutthroat Trout (Oncorhynchus clarkii utah) catch per unit effort was strongly negatively correlated with tributary channel distance, though individual growth rates were not influenced by drought metrics. We predicted the response of age 0 to age 10 cutthroat under high and low cobble availability, estimating up to a 61% decline in cutthroat CPUE when tributary channel distance is at its maximum historical value. Our study provided a unique opportunity to identify quantitative linkages between climate‐driven changes in habitat connectivity and an ecologically important endemic sportfish, expanding our understanding of potential pathways through which climate change may affect lentic ecosystems and fishes.

中文翻译：

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多年干旱及其对支流连通性的降低对副流鱼类的影响

预计全球干旱和半干旱地区多年干旱的频率和持续时间将增加，从而威胁到本地物种和生态系统功能。人们用水经常加剧多年干旱的影响，这表现为湖泊海拔降低，溪流流量减少以及水生物种的水文连通性中断。在这里，我们证明了干旱造成的湖泊水位下降通过创建海拔高度明晰的支流距离图​​而降低了支流与湖泊之间的连通性。我们将长期捕鱼量数据和湖泊高程时间序列与高程明确支流距离图​​相结合，以检验人口统计资料是否与支流连通性的干旱驱动变化有关。我们调查了犹他州贝尔湖和美国爱达荷州的沿海地区，²调查。随着湖泊高程从满水池降到最低历史高程，支流通道距离增加了3.5 km。熊湖邦纳维尔残酷鳟鱼（Oncorhynchus clarkii utah）每单位努力量的捕捞量与支流通道距离呈极显着的负相关，尽管个体的增长率不受干旱指标的影响。我们预测了在高鹅卵石和低鹅卵石可用性下0岁到10岁残酷的反应，当支流通道距离达到其最大历史值时，估计残酷CPUE下降了61％。我们的研究提供了一个独特的机会，可以确定由气候驱动的栖息地连通性变化与生态上重要的地方性运动鱼类之间的定量联系，从而加深了我们对气候变化可能影响透镜体生态系统和鱼类的潜在途径的理解。