Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Biodiversity Research Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Sci Rep. 2021 Apr 8;11(1):7725. doi: 10.1038/s41598-021-86383-z.
While climate change severely affects some aquatic ecosystems, it may also interact with anthropogenic factors and exacerbate their impact. In dry climates, dams can cause hydrological drought during dry periods following a great reduction in dam water discharge. However, impact of these severe hydrological droughts on lotic fauna is poorly documented, despite climate change expected to increase drought duration and intensity. We document here how dam water discharge was affected by climate variability during 2011-2018 in a highly modified watershed in northeastern Algeria, and how an endemic endangered lotic damselfly, Calopteryx exul Selys, 1853 (Odonata: Calopterygidae), responded to hydrological drought episodes. Analysis was based on a compilation of data on climate (temperature, precipitation, and drought index), water dam management (water depth and discharge volume and frequency), survey data on C. exul occurrence, and capture-mark-recapture (CMR) of adults. The study period was characterized by a severe drought between 2014 and 2017, which led to a lowering of dam water depth and reduction of discharge into the river, with associated changes in water chemistry, particularly during 2017 and 2018. These events could have led to the extirpation of several populations of C. exul in the Seybouse River (Algeria). CMR surveys showed that the species was sensitive to water depth fluctuations, avoiding low and high water levels (drought and flooding). The study shows that climate change interacts with human water requirements and affects river flow regimes, water chemistry and aquatic fauna. As drought events are likely to increase in the future, the current study highlights the need for urgent new management plans for lotic habitats to maintain this species and possible others.
虽然气候变化严重影响了一些水生生态系统，但它也可能与人为因素相互作用，加剧其影响。在干旱气候下，大坝可以在大坝放水大幅减少后导致干旱期的水文干旱。然而，尽管预计气候变化将延长干旱持续时间和强度，但这些严重水文干旱对流水动物区系的影响记录很少。我们在这里记录了 2011-2018 年期间，在阿尔及利亚东北部一个高度改造的流域中，气候变异性如何影响大坝放水，以及一种特有濒危流水蜻蜓，Calopteryx exul Selys，1853（蜻蜓目：Calopterygidae）如何应对水文干旱事件。分析基于对气候（温度、降水和干旱指数）、水坝管理（水深和放水体积和频率）、C. exul 发生的调查数据以及成年动物的捕获-标记-再捕获（CMR）数据的汇编。研究期间的特点是 2014 年至 2017 年期间发生了严重干旱，导致大坝水深降低，放水减少到河中，伴随的水化学变化，特别是在 2017 年和 2018 年。这些事件可能导致 Seybouse 河（阿尔及利亚）的几个 C. exul 种群灭绝。CMR 调查显示，该物种对水深波动敏感，避免低水位和高水位（干旱和洪水）。研究表明，气候变化与人类用水需求相互作用，影响河流流量模式、水化学和水生动物区系。由于未来干旱事件可能会增加，目前的研究强调需要紧急制定新的流水栖息地管理计划，以维持该物种和可能的其他物种。
