| 研究実績の概要 |
This year progress was made in elucidating the interspecific relationships between
three salmonid species (two invasive and one native) in headwater streams in Nagano Prefecture. Native white-spotted charr were found to be experiencing a combination of negative impacts (prey resource competition and direct predation) from invasive brown and brook trout (Peterson et al. 2023 Ecol. Res.). In addition, the role of submerged aquatic vegetation (SAV) in interspecific interactions in a lake dominated by an invasive predatory fish (smallmouth bass) was examined, and young-of -the- year fish were found congregated in SAV patches and utilizing them as refuge from the predator. Finally, the population genetics of native white-spotted charr in Nagano headwater streams are being examined, which will provide valuable information regarding the future conservation of native charr, and possible re-introduction efforts in areas where charr have been severely depleted.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
Good progress was made last year in elucidating the interspecific relationships between three salmonid species (two invasive and one native) in headwater streams in Nagano Prefecture. However, the removal and re-introduction part of the project was delayed due to the difficulty in receiving the required permission to proceed in the Kamikochi area of Nagano Prefecture. Therefore, plans were changed slightly to examine the ecological effects of smallmouth bass in an alpine lake, and the role that aquatic vegetation plays in mitigating theses effects.
|
| 今後の研究の推進方策 |
Going forward, this project will be moved to Toyama Prefecture, due to my appointment as an assistant professor at the University of Toyama, and the difficulty of obtaining necessary permission in Kamikochi. A variety of headwater streams will be examined in Toyama to find areas where invasive and native fish species overlap, and the ecological impacts of the invasive species will be examined. In particular, the effects of rainbow trout and smallmouth bass on native headwater fish, and entire stream ecosystems will be examined. In addition, mitigation efforts such as invasive removal, native re-introduction, and the roles of habitat complexity will be examined.
|
