Ecosystem degradation and maintenance mechanisms in dam downstream: focusing on feedback loops between periphyton and their feeders

2014 Fiscal Year Final Research Report

• Project/Area Number: 24710039
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental impact assessment/Environmental policy
• Research Institution: The University of Tokyo (2014); Public Works Research Institute (2012-2013)
• Principal Investigator: MORI Terutaka 東京大学, 総合文化研究科, 特別研究員 (50600095)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 濁水 / シルト / 掃流砂 / 付着藻類 / 水生昆虫 / アユ

Outline of Final Research Achievements

To clarify processes that provide overgrowth of periphyton and disappearance of algivore in dam downstream, both of which are different with stream ecosystems in natural conditions, we conducted laboratory and field manipulation experiments. Drainage of turbid water and absence of bed loads due to dam reservoirs had effects on periphyton, and in some cases the both contributed to overgrowth of periphyton. Disappearance of algivore such as stream insects may result from two factors, scarce of sand which is used as stone case and alteration of periphyton as food resources. In addition, their disappearances triggered overgrowth of periphyton, and thus we showed that the both the overgrowth and the disappearance is closely linked to each other.

Free Research Field

河川生態学