Updated on 2026/05/15

写真a

 
TAKATSU Kunio
 
Organization
Sado Island Center for Ecological Sustainability . Associate Professor
Faculty of Science Associate Professor
Title
Associate Professor
External link

Degree

  • 博士(環境科学) ( 2017.3   北海道大学 )

  • 修士(環境科学) ( 2013.3   北海道大学 )

Research History

  • Niigata University   Faculty of Science   Associate Professor

    2023.4

  • Niigata University   Associate Professor

    2023.4

 

Papers

  • Non‐Consumptive Effects of Predators on Prey That Outgrow the Predation Window

    Riko Urushihara, Kunio Takatsu

    Freshwater Biology   2026.4

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1111/fwb.70223

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  • To Metamorphose or Overwinter? The Case of an Endangered Anuran Endemic

    Kunio Takatsu

    Wetlands   45 ( 1 )   2024.12

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s13157-024-01875-8

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    Other Link: https://link.springer.com/article/10.1007/s13157-024-01875-8/fulltext.html

  • Glacial Meltwater Increases the Dependence on Marine Subsidies of Fish in Freshwater Ecosystems

    Grégoire Saboret, Coralie Moccetti, Kunio Takatsu, David J. Janssen, Blake Matthews, Jakob Brodersen, Carsten J. Schubert

    Ecosystems   27 ( 6 )   779 - 796   2024.6

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    In a warming world, the input of glacier meltwater to inland water ecosystems is predicted to change, potentially affecting their productivity. Meta-ecosystem theory, which posits that the nutrient availability in the recipient ecosystem can determine the extent of cross-ecosystem boundary utilization, can be useful for studying landscape-scale influences of glacier meltwater on inland waters. Here, we investigate how the input of glacier meltwater in a river system in Southern Greenland influences the utilization of marine subsidies in freshwater fish. Our study system comprised four sites, with controls for glacial meltwater and marine subsidies, harboring a partially migrating population of arctic char, meaning that some individuals migrate to the ocean and others remain in freshwaters, and two fully resident populations as a freshwater reference. We assessed the incorporation of marine carbon in freshwater resident char using both bulk and amino acid stable isotope analysis of muscle tissue. In the population with partial migration, marine subsidies were a significant resource for resident char individuals, and estimates of trophic position suggest that egg cannibalism is an important mechanism underlying the assimilation of these marine subsidies. In proglacial streams, namely those with high glacial meltwater, the total dependence on marine subsidies increased and reached 83% because char become cannibals at smaller sizes. In the configuration of our focal meta-ecosystem, our results suggest that the importance of marine subsidies to freshwater fish strengthens within increasing meltwater flux from upstream glaciers.

    DOI: 10.1007/s10021-024-00920-1

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    Other Link: https://link.springer.com/article/10.1007/s10021-024-00920-1/fulltext.html

  • Relationships between egg size and maternal size, life history forms, and habitats of Greenlandic Arctic charr (Salvelinus alpinus)

    Kunio Takatsu, Coralie Delarue, Naomi Heller, Grégoire Saboret, Jakob Brodersen

    Environmental Biology of Fishes   2023.5

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1007/s10641-022-01374-x

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  • Repeated elevational clines of early life‐history traits and their proximate mechanisms in brown trout

    Kunio Takatsu, Jakob Brodersen

    Freshwater Biology   2023.4

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1111/fwb.14050

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  • Temperature regime during embryogenesis alters subsequent behavioural phenotypes of juvenile brown trout

    Kunio Takatsu, Oliver M. Selz, Jakob Brodersen

    Biology Letters   2022.11

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1098/rsbl.2022.0369

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  • Predator cannibalism can shift prey community composition toward dominance by small prey species

    Kunio Takatsu

    Ecology and Evolution   2022.5

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/ece3.8894

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  • Enhanced recruitment of larger predators in the presence of large prey

    Kunio Takatsu, Osamu Kishida

    Journal of Animal Ecology   89 ( 7 )   1615 - 1627   2020.4

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    Abstract

    Most carnivores undergo diet shift from smaller to larger prey items during ontogeny. The trophic relationship between a growing carnivore and larger prey is representative of a size‐structured predator–prey interaction. The strength of this interaction is, in part, determined by the recruitment of individuals from smaller predatory size classes into larger predatory size classes. Therefore, it is interesting to investigate how larger prey alter the recruitment of smaller predator size classes into larger predator size classes, since this can affect their own future predation risk.

    Past empirical studies have exclusively documented that large prey reduce predator recruitment by decreasing growth and/or survival of the smaller predators. In this study, we provide empirical evidence of the contrasting pattern: large prey enhance the recruitment of smaller predators into larger predators even though they increase cannibalism mortality of the smaller predators. We have done this here by studying the trophic interaction between predatory salamander larvae Hynobius retardatus and the frog tadpoles Rana pirica that represent their large prey.

    In a field experiment in which salamander hatchlings were exposed to the presence or absence of large frog tadpoles, we found that more giant salamanders emerged in the presence of frog tadpoles than in their absence. Reassignment of frog tadpoles (to both treatments) in the subsequent experimental period showed that the enhanced emergence of giant salamanders in the presence of frog tadpoles leads to the intensification of salamander predation on the frog tadpoles.

    In an additional laboratory experiment, to better understand the underlying mechanisms, we manipulated both the presence of frog tadpoles and the occurrence of cannibalism between salamander hatchlings. This experiment revealed that frog tadpoles intensify the cannibalism of salamander larvae during their hatchling stage, thus allowing more salamander larvae to become large‐sized predators.

    Our results suggest that frog tadpoles can inadvertently intensify their own future predation risk by intensifying cannibalistic interactions among predatory salamander hatchlings, thereby enhancing the degree of predator recruitment to a larger size class. Hence, large prey can enhance the recruitment of individuals from small predator size classes into larger predator size classes.

    DOI: 10.1111/1365-2656.13210

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1111/1365-2656.13210

  • Giant cannibals drive selection for inducible defence in heterospecific prey

    Kunio Takatsu, Volker H. W. Rudolf, Osamu Kishida

    Biological Journal of the Linnean Society   2016.11

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    Publishing type:Research paper (scientific journal)   Publisher:Oxford University Press ({OUP})  

    DOI: 10.1111/bij.12912

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  • Contacts with large, active individuals intensify the predation risk of small conspecifics

    Aya Yamaguchi, Kunio Takatsu, Osamu Kishida

    Ecology   97 ( 11 )   3206 - 3218   2016.11

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/ecy.1543

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  • Predator cannibalism can intensify negative impacts on heterospecific prey

    Kunio Takatsu, Osamu Kishida

    Ecology   96 ( 7 )   1887 - 1898   2015.7

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1890/14-1616.1

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  • Allometric equations for estimation of energy contents from body length for common amphibians (Hynobius retardatus and Rana pirica) in Hokkaido, Japan

    Kunio Takatsu, Osamu Kishida

    Herpetology Notes   2015.4

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    Publishing type:Research paper (scientific journal)  

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  • Adaptive acceleration in growth and development of salamander hatchlings in cannibalistic situations

    Osamu Kishida, Ayumi Tezuka, Akiko Ikeda, Kunio Takatsu, Hirofumi Michimae

    Functional Ecology   29 ( 4 )   469 - 478   2014.11

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1111/1365-2435.12361

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  • An offensive predator phenotype selects for an amplified defensive phenotype in its prey

    Kunio Takatsu, Osamu Kishida

    Evolutionary Ecology   27 ( 1 )   1 - 11   2012.4

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Nature  

    DOI: 10.1007/s10682-012-9572-4

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Research Projects

  • 個体成長に伴う食う-食われる関係の解消以降も捕食者種と餌種は影響しあうか?

    Grant number:25K00281

    2025.4 - 2028.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    高津 邦夫

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    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

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  • 越冬環境の泥と水の深さがサドガエル幼生の越冬成功と翌春以降の成長・発生に与える影響:江やビオトープを重視した保全対策の改善に向けて

    2023.9 - 2024.8

    Awarding organization:公益信託 富士フイルム・グリーンファンド

    高津邦夫

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  • 水深の変化がサドガエルの変態時の特徴に与える影響:江やビオトープを重視した保全対策の改善に向けて

    2023.5 - 2024.3

    Awarding organization:公益信託 増進会自然環境保全研究活動助成基金

    高津邦夫

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  • 捕食者の共食いの生態学的意義:個体の特徴に注目して

    Grant number:13J03564

    2013.4 - 2016.3

    System name:科学研究費助成事業

    Research category:特別研究員奨励費

    Awarding organization:日本学術振興会

    高津 邦夫

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    Grant amount:\3600000 ( Direct Cost: \3600000 )

    密度依存の死亡率は個体群密度を制御する重要なプロセスである。餌種の密度依存の死亡率は、餌種の密度増加に伴う捕食者との遭遇率の増加によってもたらされると考えられてきた。本研究は、サイズ関係によって捕食-被食関係が結ばれるかどうかが決まる系の場合、単純な捕食者との遭遇率以外の文脈で、餌種の密度依存の死亡率が生じることがあることを報告する。
    餌種の密度の増加は餌種内の競争を強め、餌種のサイズ成長を抑制する。このため、餌種の密度が高いほど餌種は小さく、捕食者に食われやすいと考えられる。結果として、餌種の密度が高いほど餌種の捕食死亡率が高まると予測した。この一連の予測を実証するために実験を行った。実験には捕食者としてエゾサンショウウオ幼生(以下サンショ)とその餌種としてエゾアカガエルのオタマジャクシ(オタマ)からなる系を使った。野外実験において餌種であるオタマの密度が高いほど捕食死亡率が高いことを確かめた。そして、オタマの密度依存の捕食死亡率が生じた詳細なメカニズムを明らかにするために、サンショの在不在とオタマの密度の高低を組み合わせた室内実験を行った。実験初期、サンショの在不在や密度の高低に関わらず全てのオタマが生き残ったが、高密度区のオタマは概して小さかった。その後、サンショとの遭遇率をそろえるために、高密度区と低密度区のオタマの密度をそろえ、各処理区での再操作以降のオタマの死亡率を調べた。再操作以降、高密度区由来のオタマがサンショのいる処理区でのみよく死んだ、つまり、サンショによく食われた。以上の結果は、1)餌種の密度の増加とともに競争が激化し餌種のサイズ成長は悪化するため、2)餌種の密度が高いほど、餌種は捕食者に比べて小さく食われやすくなり、3)結果として、餌種の密度依存の死亡率が生じることを示し、これは予測と一致する。本研究は密度依存の死亡率が生じる新たなメカニズムを提示する。

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Teaching Experience

  • フィールド科学特論

    2026
    Institution name:新潟大学

  • 科学英語演習

    2026
    Institution name:新潟大学

  • 卒業論文

    2025
    Institution name:新潟大学

  • 佐渡自然共生国際実習

    2024
    Institution name:新潟大学

  • 希少生物学特論

    2024
    Institution name:新潟大学

  • 卒業論文I

    2024
    Institution name:新潟大学

  • 個体群生態学特論

    2024
    Institution name:新潟大学

  • 希少生物保全学

    2024
    Institution name:新潟大学

  • 卒業論文II

    2024
    Institution name:新潟大学

  • 佐渡学概論:佐渡島の自然と人々の営み

    2024
    Institution name:新潟大学

  • 環境ガバナンス概論

    2024
    Institution name:新潟大学

  • 環境ファシリテーター論及び演習

    2024
    Institution name:新潟大学

  • 森・里・海フィールド実習

    2023
    Institution name:新潟大学

  • 自然再生学実習

    2023
    Institution name:新潟大学

  • 里地里山再生学

    2023
    Institution name:新潟大学

  • 朱鷺・自然再生フィールドワーク

    2023
    Institution name:新潟大学

  • トキをシンボルとした自然再生

    2023
    Institution name:新潟大学

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