Spring-fed streams as flow refugia: Changes in fish assemblages after a rainfall event
Spring-fed streams as flow refugia: Changes in fish assemblages after a rainfall event
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DOI：
10.1101/2020.04.26.062968
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
M. Sakai;Ryoshiro Wakiya;Gosuke Hoshi
中科院分区：
文献类型：
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作者：
M. Sakai;Ryoshiro Wakiya;Gosuke Hoshi
了解河网中水流保护区的结构和功能对于在水流人为变化的背景下保护淡水至关重要。与洪水期间现场数据收集相关的安全问题在很大程度上阻碍了鱼类流域保护区评估的进展；然而，由于泉水溪流的水流稳定，因此在降雨期间可以安全地测量泉水溪流。在这项研究中，我们评估了日本北部低地泉水支流在 48.5 毫米降雨事件后鱼类群落的时间变化。总共收集了七种鱼类，不同物种对洪水的反应各不相同。鲑鱼（Oncorhynchus keta 和 O. masou masou）的数量在降雨后立即增加，但随后减少。 O. keta 的集合完全由成熟个体组成，而 O. masou masou 的集合仅包括幼体，这表明前者使用支流产卵，而 O. masou masou 可能在降雨事件期间疏散到支流中。底栖物种（Cottushangiongensis 和 Gymnogobius opperiens）仅在正常水流条件下在干流中观察到，在洪水期间在支流中没有出现，表明这些物种可以利用其他水流保护区。我们的结果表明，泉水支流可能为游泳生物物种提供流动避难所，而底质偏好可能是泉水支流是否充当底栖物种流动避难所的主要决定因素。
Understanding the structure and function of flow refugia in river networks is critical to freshwater conservation in the context of anthropogenic changes in flow regimes. Safety concerns associated with field data collection during floods have largely hindered advances in assessing flow refugia for fishes; however, spring-fed streams can be safely surveyed during rainfall events owing to their stable flow regimes. In this study, we assessed temporal changes in fish assemblages in a lowland, spring-fed tributary in northern Japan after a 48.5 mm rainfall event. A total of seven fish species were collected, and responses to the flood varied among species. Abundance of salmonids (Oncorhynchus keta and O. masou masou) increased immediately after rainfall but subsequently decreased. Collections of O. keta consisted entirely of mature individuals, while O. masou masou collections included only juveniles, suggesting that the former uses the tributary for spawning whereas O. masou masou may evacuate into the tributary during rainfall events. Benthic species (Cottus hangiongensis and Gymnogobius opperiens) were only observed in the main stream under ordinary flow conditions, and did not appear in the tributary during the flood, suggesting that other flow refugia are available to these species. Our results suggest that spring-fed tributaries may provide flow refugia for nekton species, whereas substrate preferences may be the major determinant of whether spring-fed tributaries function as flow refugia for benthic species.