Elimination of a major distributional barrier by Japan's first dam removal project: The transition in the gene flow scale of aquatic organisms caused by the re-establishment of a flowing river network

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14807
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Ecology/Environment
• Research Institution: Shinshu University
• Principal Investigator: Tojo Koji 信州大学, 学術研究院理学系, 教授 (30377618)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: ダム撤去事業 / 流水ネットワーク / 移動分散 / 遺伝子流動 / 集団遺伝 / 水生昆虫 / 自然再生 / 遺伝的多様性

Outline of Final Research Achievements

Japan's first dam removal project was undertaken at the Arase Dam on Kumagawa River during the years 2013 to 2018. The dam reservoir, which existed for ca. 60 years, drained away as the up- and downstream sides of the dam site and their tributaries were reconnected as a flowing water network. The major obstacle in dispersion of stream inhabiting organisms was completely eliminated. Removal of the dam re-enables the dispersion of organisms adapted to running water environments. As a result, it is expected to have a positive influence on their scale of gene flow.

This study records for future comparison the genetic structure analyses of an aquatic insect collected immediately before the project. These analyses are treated as base data on genetic structure before the project. In the future, I plan to compare them with the data of genetic structure after dam removal. So, this constitutes the extremely important fundamental data to verify the effects of Japan’s first dam removal project.

Free Research Field

進化生物学