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Time Series Changes in Fish Assemblages and Habitat Structures Caused by Partial Check Dam Removal
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Title: | Time Series Changes in Fish Assemblages and Habitat Structures Caused by Partial Check Dam Removal |
Authors: | Nagayama, Shigeya Browse this author | Ishiyama, Nobuo Browse this author | Seno, Taro Browse this author | Kawai, Hideyuki Browse this author | Kawaguchi, Yoichi Browse this author | Nakano, Daisuke Browse this author | Nakamura, Futoshi Browse this author →KAKEN DB |
Keywords: | bedrock outcrop | ecological trade-off | habitat preference | long-term monitoring | sediment transportation |
Issue Date: | Dec-2020 |
Publisher: | MDPI |
Journal Title: | Water |
Volume: | 12 |
Issue: | 12 |
Start Page: | 3357 |
Publisher DOI: | 10.3390/w12123357 |
Abstract: | Despite a steep increase in dam removal projects, there are few studies on the biophysical responses to dam removal. In this study, we evaluated the short-term (1.5 years) and long-term (5.5 years) effects of partial check dam removal on fish assemblages and their habitats. First, the habitat preferences of fish were examined at a channel unit scale: pools, rapids, and side channels satisfied the seasonal habitat requirements of the fish assemblages. Partial check dam removal increased the abundance of these habitats and diversified the habitat structures owing to the sediment release from the dam; in contrast, the bedrock distinctly decreased 1.5 years after dam removal. However, 5.5 years after dam removal, the bedrock proportion increased, and the habitat structures were simplified again owing to the re-transportation of sediments. Similar temporal changes were also determined through a reach-scale analysis with a change in the bed materials. Anadromous Oncorhynchus masou began to spawn and recolonize in the upstream section of the dam after the dam removal, causing similar assemblage compositions between the downstream and upstream sections. The abundance of Salvelinus malma and Noemacheilus barbatulus toni in the upstream reaches decreased over time after the dam removal. The temporal changes in the biophysical responses suggest that long-term monitoring is indispensable for the reliable evaluation of dam removal effects. |
Rights: | https://creativecommons.org/licenses/by/4.0/ |
Type: | article |
URI: | http://hdl.handle.net/2115/80411 |
Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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