Updated on 2023/04/20


OKADA Keiichi

Assistant Professor


Assistant Professor

Contact information

Contact information



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From School 【 display / non-display

  • Tokyo University of Agriculture   Faculty of Regional Environment Science   Graduated

    2001.04 - 2005.03

From Graduate School 【 display / non-display

  • Shinshu University   Master Course   Completed

    2005.04 - 2007.03

Degree 【 display / non-display

  • Ph.D. ( 2011.03 )

Employment Record in Research 【 display / non-display

  • Tokyo University of Agriculture   Faculty of Bio-Industry   Department of Northern Biosphere Agriculture   Assistant Professor


Research Areas 【 display / non-display

  • Life Science / Forest science

Research Interests 【 display / non-display

  • mycorrhizal symbiosis

  • ecosystem ecology

  • matter cycling

  • functional ecology

  • forest ecology

Papers 【 display / non-display

  • Termite sensitivity to temperature affects global wood decay rates Reviewed

    Amy E. Zanne, Habacuc Flores-Moreno, Jeff R. Powell, William K. Cornwell, James W. Dalling, Amy T. Austin, Aimée T. Classen, Paul Eggleton, Kei-ichi Okada, Catherine L. Parr, E. Carol Adair, Stephen Adu-Bredu, Md Azharul Alam, Carolina Alvarez-Garzón, Deborah Apgaua, Roxana Aragón, Marcelo Ardon, Stefan K. Arndt, Louise A. Ashton, Nicholas A. Barber, Jacques Beauchêne, Matty P. Berg, Jason Beringer, Matthias M. Boer, José Antonio Bonet, Katherine Bunney, Tynan J. Burkhardt, Dulcinéia Carvalho, Dennis Castillo-Figueroa, Lucas A. Cernusak, Alexander W. Cheesman, Tainá M. Cirne-Silva, Jamie R. Cleverly, Johannes H. C. Cornelissen, Timothy J. Curran, André M. D’Angioli, Caroline Dallstream, Nico Eisenhauer, Fidele Evouna Ondo, Alex Fajardo, Romina D. Fernandez, Astrid Ferrer, Marco A. L. Fontes, Mark L. Galatowitsch, Grizelle González, Felix Gottschall, Peter R. Grace, Elena Granda, Hannah M. Griffiths, Mariana Guerra Lara, Motohiro Hasegawa, Mariet M. Hefting, Nina Hinko-Najera, Lindsay B. Hutley, Jennifer Jones, Anja Kahl, Mirko Karan, Joost A. Keuskamp, Tim Lardner, Michael Liddell, Craig Macfarlane, Cate Macinnis-Ng, Ravi F. Mariano, M. Soledad Méndez, Wayne S. Meyer, Akira S. Mori, Aloysio S. Moura, Matthew Northwood, Romà Ogaya, Rafael S. Oliveira, Alberto Orgiazzi, Juliana Pardo, Guille Peguero, Josep Penuelas, Luis I. Perez, Juan M. Posada, Cecilia M. Prada, Tomáš Přívětivý, Suzanne M. Prober, Jonathan Prunier, Gabriel W. Quansah, Víctor Resco de Dios, Ronny Richter, Mark P. Robertson, Lucas F. Rocha, Megan A. Rúa, Carolina Sarmiento, Richard P. Silberstein, Mateus C. Silva, Flávia Freire Siqueira, Matthew Glenn Stillwagon, Jacqui Stol, Melanie K. Taylor, François P. Teste, David Y. P. Tng, David Tucker, Manfred Türke, Michael D. Ulyshen, Oscar J. Valverde-Barrantes, Eduardo van den Berg, Richard S. P. van Logtestijn, G. F. (Ciska) Veen, Jason G. Vogel, Timothy J. Wardlaw, Georg Wiehl, Christian Wirth, Michaela J. Woods, Paul-Camilo Zalamea

    Science   377 ( 6613 )   1440 - 1444   2022.09

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    Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science (AAAS)  

    Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)—even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth’s surface.

    DOI: 10.1126/science.abo3856


  • Biodiversity–productivity relationships are key to nature-based climate solutions Reviewed

    Akira S. Mori, Laura E. Dee, Andrew Gonzalez, Haruka Ohashi, Jane Cowles, Alexandra J. Wright, Michel Loreau, Yann Hautier, Tim Newbold, Peter B. Reich, Tetsuya Matsui, Wataru Takeuchi, Kei-ichi Okada, Rupert Seidl, Forest Isbell

    Nature Climate Change   11 ( 6 )   543 - 550   2021.06

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

    DOI: 10.1038/s41558-021-01062-1


    Other Link: http://www.nature.com/articles/s41558-021-01062-1

  • A meta-analysis on decomposition quantifies afterlife effects of plant diversity as a global change driver Reviewed

    Akira S. Mori, J. Hans C. Cornelissen, Saori Fujii, Kei-ichi Okada, Forest Isbell

    Nature Communications   11 ( 1 )   2020.12

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

    © 2020, The Author(s). Biodiversity loss can alter ecosystem functioning; however, it remains unclear how it alters decomposition—a critical component of biogeochemical cycles in the biosphere. Here, we provide a global-scale meta-analysis to quantify how changes in the diversity of organic matter derived from plants (i.e. litter) affect rates of decomposition. We find that the after-life effects of diversity were significant, and of substantial magnitude, in forests, grasslands, and wetlands. Changes in plant diversity could alter decomposition rates by as much as climate change is projected to alter them. Specifically, diversifying plant litter from mono- to mixed-species increases decomposition rate by 34.7% in forests worldwide, which is comparable in magnitude to the 13.6–26.4% increase in decomposition rates that is projected to occur over the next 50 years in response to climate warming. Thus, biodiversity changes cannot be solely viewed as a response to human influence, such as climate change, but could also be a non-negligible driver of future changes in biogeochemical cycles and climate feedbacks on Earth.

    DOI: 10.1038/s41467-020-18296-w




  • Habitat use of Bornean Ferret Badger Melogale everetti in Sabah, Malaysian Borneo Reviewed

    Hidemi NAGANO, Keiichi OKADA, Yoshihiro NAKASHIMA, Hiromitsu SAMEJIMA, Jamili NAIS, Kanehiro KITAYAMA

    Small Carnivore Conservation   57   25 - 33   2019.01

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    Language:English   Publishing type:Research paper (scientific journal)  

  • Reconsidering biodiversity hotspots based on the rate of historical land-use change Reviewed

    Yuta Kobayashi, Kei-ichi Okada, Akira S. Mori

    Biological Conservation   233   2019

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    Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.biocon.2019.02.032

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Books and Other Publications 【 display / non-display

  • 森林学の百科事典

    日本森林学会編( Role: Contributor)

    丸善出版  2021.01 

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    Language:Japanese   Book type:Scholarly book

Misc 【 display / non-display

  • Evaluating demographic non-equilibrium of tree population: four-decade study in a late-successional subalpine forest

    Suzuki Kureha, Kitagawa Ryo, Koide Dai, Okada Kei-ichi, Mori Akira S

    The Japanese Forest Society Congress   131   477   2020.05

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    Language:Japanese   Publisher:THE JAPANESE FORESTRY SOCIETY  

    [in Japanese]

    DOI: 10.11519/jfsc.131.0_477

    CiNii Articles


Scientific Research Funds Acquisition Results 【 display / non-display

  • 土壌への根系到達による倒木更新木の栄養制限緩和と更新の成否

    Grant number:22K05730  2022.04 - 2025.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    岡田 慶一

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )


Other External Funds 【 display / non-display

  • 根系発達と倒木腐朽度の時系列動態から紐解く倒木更新の成否

    2021.06 - 2022.03

    農生命科学研究所  2021 年度 若手・女性研究者支援プロジェクト 


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    Authorship:Principal investigator 

    Grant amount:\1000000 ( Direct Cost: \1000000 )

  • 熱帯林における菌根菌の菌糸体生産と栄養獲得機能の解明

    2014.04 - 2015.03

    民間財団等  藤原ナチュラルヒストリー振興財団 


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    Authorship:Principal investigator  Grant type:Competitive

  • 熱帯林における外生菌根菌の菌糸体生産と栄養獲得機能の解明

    2014.04 - 2015.02

    民間財団等  笹川科学研究助成 


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    Authorship:Principal investigator  Grant type:Competitive

Presentations 【 display / non-display

  • 冷温帯天然林における伐根サイズに応じた針葉樹実生更新状況の変化

    岡田慶一, 中濱和紀, 西村祥紀, 時田勝広

    第 134 回⽇本森林学会⼤会  2023.03 

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    Language:Japanese   Presentation type:Poster presentation  


Teaching Experience 【 display / non-display

  • 森林環境科学


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  • 育林学


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  • Exercise in Geographic Information Analysis

    2022.04 Institution:Tokyo University of Agriculture

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  • Practical training in forestry

    2021.04 Institution:Tokyo University of Agriculture

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  • English for Science

    2021.04 Institution:Tokyo University of Agriculture

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Committee Memberships 【 display / non-display

  • Ecological Society of Japan   Copy editor of Ecological Research  

    2015.05 - 2020.03   

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    Committee type:Academic society