Disentangling the influence of historical contingency on the diversity of migratory routes of Japanese birds

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20670
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0703:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Forest Research and Management Organization
• Principal Investigator: Aoki Daisuke 国立研究開発法人森林研究・整備機構, 森林総合研究所, 任期付研究員 (80963818)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: 渡り鳥 / 生物地理学 / 集団ゲノミクス / 歴史的偶然性 / 適応進化 / バイオロギング

Outline of Final Research Achievements

Migratory species have their own routes to travel long distances. It remains unexplored what evolutionary processes were responsible for generating the diversity of migratory routes. In this study, we aimed to examine a hypothesis that interspecific differences in migratory routes have evolved due to different evolutionary histories of each species (historical contingency). We aimed to accomplish this by integrating an analysis of migratory trajectories and phylogeography. First, in several migratory birds, I used phylogeography consisting of population genetics and species distribution modeling to reconstruct the continental ancestral areas. Next, I conducted mathematical simulation to examine whether migratory routes were constrained to this region. As a result, I inferred that interspecific differences in the migratory routes of Brown shrikes and Stejneger's Stonechats may be explained by historical contingency.

Free Research Field

進化生態学

Academic Significance and Societal Importance of the Research Achievements

渡り鳥は、何千キロもの往復移動を安全に移動するために、種ごとに特有の渡り経路を進化させてきた。近年の人為的な環境変動によって、渡り経路の環境は劣化している。渡り鳥は渡り経路を変更することで生存を迫られているが、多くの渡り鳥は荒廃した環境を今もなお利用している。先行研究は渡り経路が柔軟に環境に適応すると考えてきたが、多くの渡り鳥が渡り経路を変更できていない理由を説明できなかった。本研究成果は、渡り経路が種ごとの歴史に制約されることで種特有の経路が進化した可能性を示唆した。多くの渡り鳥は急な環境変動に適応する柔軟性を失っている可能性があり、渡り鳥の進化理論の再考の必要性を迫る。