| Project/Area Number |
18K05807
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 40030:Aquatic bioproduction science-related
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| Research Institution | The University of Tokyo (2022)
Hokkaido University (2020-2021)
Fisheries Research and Education Agency (2018-2019) |
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Principal Investigator |
Morita Kentaro 東京大学, 大気海洋研究所, 教授 (30373468)
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| Co-Investigator(Kenkyū-buntansha) |
坪井 潤一 国立研究開発法人水産研究・教育機構, 水産資源研究所(横浜), 主任研究員 (80524694)
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥130,000 (Direct Cost: ¥100,000、Indirect Cost: ¥30,000)
Fiscal Year 2021: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 種間競争 / サケ科魚類 / 流程分布 / 水温 |
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| Outline of Final Research Achievements |
Many studies have reported longitudinal distribution and niche partitioning in streams containing two salmonid species, but whether these reported patterns occur also in streams containing three-or-more salmonid species is poorly known. We examined abiotic environmental variables and population densities of three salmonids. Dolly Varden were more abundant in reaches with lower maximum water temperature and higher elevation, masu salmon were more abundant in reaches with faster water velocity, and charr were more abundant in reaches with moderate water velocity with higher water temperature. In a two-species charr-and-salmon system, charr occur farther upstream than salmon, but in a three-species system that includes Dolly Varden upstream, salmon appeared farther upstream than charr. The consequences of interspecific interactions among three competing species may lead to deadlock conditions that differ from two-species systems, including the range of species coexistence.
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| Academic Significance and Societal Importance of the Research Achievements |
古典的なLotoka-Volterraモデルによれば、２種系の場合は種間競争が強いと共存できないが、３種になると全ての種が共存し続けることが可能になることがある。そのため、種の多様性の維持を理解するためには、多様な競争ネットワーク構造から生じる共存メカニズムを探究することが求められる。サケ科魚類の流程分布とそれに関連した種間相互作用について多大な関心がもたれてきたが、その多くは２種系のシステムを扱ったものがほとんどである。本研究では、これまで２種系で知られていた種間相互作用やハビタット分割が３種以上の系では必ずしも成立しないことを示し、ニッチが近い競争関係にある複数種の共存機構を提示した。
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