2015 Fiscal Year Final Research Report
Long-term impacts of forest managements on the river ecosystems using stable nitrogen isotopic ratios of amino acids
Project/Area Number |
25660120
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Research Category |
Grant-in-Aid for Challenging Exploratory Research
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Allocation Type | Multi-year Fund |
Research Field |
Forest science
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Research Institution | Japan Fisheries Research and Education Agency |
Principal Investigator |
Togashi Hiroyuki 国立研究開発法人水産総合研究センター, その他部局等, 研究員 (80616110)
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Project Period (FY) |
2013-04-01 – 2016-03-31
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Keywords | 炭素・窒素安定同位体比 / アミノ酸の窒素安定同位体比 / 放射性炭素14 / 河川生態系 / 水生昆虫 / 森林管理 |
Outline of Final Research Achievements |
The present study was to clarify the long-term impacts of clear-cutting and replanting on the stream ecosystems using multi-isotopes. Macroinvertebrates were collected in six streams of stand ages from 5 to >90 yr. The mean δ13C values of macroinvertebrates decreased with increasing stand ages. The result indicates the macroinvertebrates in old-stand ages depended more on terrestrial resources. From δ15N of amino acids, it was possible to estimate the contribution rate of aquatic vs. terrestrial resources and the trophic level of each taxon. The Δ14C values of both periphyton and grazers were lower than that of modern atmospheric CO2. These suggest that soil CO2 released by groundwater, and that dissolved inorganic carbon with low Δ14C is incorporated into stream ecosystems. The ecological response in the studied streams to forest managements is much slower than the chemical response. More than 50 yr is required for the food web structure to completely recover from clear-cutting.
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Free Research Field |
同位体生態学
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