Regeneration traits and genetic diversity of relic tree species in Oki islands

• Project/Area Number: 18K05727
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: Shimane University
• Principal Investigator: Kubo Masako 島根大学, 学術研究院環境システム科学系, 准教授 (70535468)
• Co-Investigator(Kenkyū-buntansha): 崎尾 均 新潟大学, 佐渡自然共生科学センター, 教授 (20449325) ; 須貝 杏子 島根大学, 学術研究院農生命科学系, 助教 (20801848)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2019: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 氷河期遺存樹種 / 隠岐諸島 / ヒメコマツ / クロベ / ミズナラ / カツラ / 日本海島嶼

Outline of Final Research Achievements

Oki islands have unique forests, where the relic tree species of the glacial age grow in the warm-temperate zone. In the result of the survey of the distribution of the relic species, Pinus parviflora grows on the rocky mountains, Thuja standishii grows from the coastal area to the mountain area, and Cercidiphyllum japonicum grows in the riparian area. Although Quercus crispula grows from the coastal to the mountain area, they distributed mainly in the northern area of the islands, because it’s cool and it has a lot of precipitation due to the seasonal northwest wind. Also, in the result of the analysis of the genetic diversity, it is suggested that T. standishii made Oki Islands a refuge during the glacial age. Therefore, Oki Islands are important places for understanding the spread of trees by the climate change in Japan.

Academic Significance and Societal Importance of the Research Achievements

隠岐諸島は日本で６番目に認定された世界ジオパークであり，暖温帯林に冷温帯の樹種が存在する植生の固有性は，世界ジオパークの認定に大きな役割を果たした。本研究成果は，こうした固有の森林植生の維持機構を明らかにし，さらに隠岐諸島が氷河期のレフュジアとして重要な役割を果たした可能性を示した。本成果は，隠岐諸島の森林資源の保全や活用においての学術的基礎資料を提供するものである。

Research Products

• [Journal Article] Genetic Distinctiveness but Low Diversity Characterizes Rear-Edge Thuja standishii (Gordon) Carr. (Cupressaceae) Populations in Southwest Japan (2021)
  • Author(s): James R. P. Worth, Ichiro Tamaki, Ikutaro Tsuyama, Peter A. Harrison, Kyoko Sugai, Hitoshi Sakio, Mineaki Aizawa and Satoshi Kikuchi
  • Journal Title: Diversity Volume: 13(59) Issue: 5 Pages: 185-185
  • DOI: 10.3390/d13050185
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] 隠岐諸島の維管束植物目録 (2020)
  • Author(s): 須貝杏子・毛利元樹・久保満佐子・井上雅仁・亀山智史・林蘇娟
  • Journal Title: 島根県立三瓶自然館研究報告 Volume: 18 Pages: 7-30
• [Presentation] 隠岐諸島におけるミズナラの分布特性と成林条件 (2021)
  • Author(s): 立花寛奈
  • Organizer: 隠岐ユネスコ世界ジオパーク推進協議会令和2年度学術研究発表会