A model study to understand the formation history of East Asian temperate forests under the Miocene-Pliocene climate changes

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K04154
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17050:Biogeosciences-related
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: Yabe Atsushi 独立行政法人国立科学博物館, 地学研究部, 研究主幹 (20634124)
• Co-Investigator(Kenkyū-buntansha): 齊藤 毅 名城大学, 理工学部, 准教授 (50242813)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 日本列島温帯林 / 植生史 / ブナ優占林 / 中新ー鮮新世

Outline of Final Research Achievements

To elucidate the evolutionary history of temperate forests in East Asia, we have worked on the Miocene and Pliocene beech-dominated forests as a model case. First, we studied three Mio-Pliocene fossil-bearing strata in the Japanese archipelago and elucidated the composition of fossil assemblages and the phylogeny of fossil beech species. Fagus stuxbergii-dominated forests were established in central and western Japan, while F. palaeojaponica became dominant in northeastern Honshu and Hokkaido. The occurrence of both species dates back to the middle Miocene, indicating that beech-dominated forests are strongly associated with cooling of climatic conditions. On the other hand, these fossil species were revealed to be phylogenetically distant from the two endemic species in Japan, and the Miocene-Pliocene beech-dominated forests are not directly comparable to present-day temperate forests.

Free Research Field

古植物学

Academic Significance and Societal Importance of the Research Achievements

東アジアにはブナ属が優占する温帯林が広がり、森林動態的にも重要な地位を占めることから、その成立過程の解明が生物多様性の保全や地球環境変化への応答を予見するうえで課題となっていた。本研究では、２種のブナ属固有種が優占林を形成する日本列島をモデルに、従来、温帯林成立期とされてきた中新ー鮮新世の３つ化石群集の年代・群集組成、古気候条件とブナ属の系統解明に取り組んだ。本研究により、中新ー鮮新世の森林が現在の温帯林と相同ではなく、大陸との種の交流により多くの絶滅要素を含む特異なものだったこと、成立背景に気候変化と古地理の特性があったことが示され、多様性をもたらした要因の一部を示すことができた。