Human activities maintaining raptor populations in traditional agricultural landscapes and their geographical differences in Japan

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K05683
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39060:Conservation of biological resources-related
• Research Institution: The University of Tokyo
• Principal Investigator: Fujita Tsuyoshi 東京大学, 大学院農学生命科学研究科(農学部), 助教 (80302595)
• Co-Investigator(Kenkyū-buntansha): 東 淳樹 岩手大学, 農学部, 講師 (10322968) ; 片山 直樹 国立研究開発法人農業・食品産業技術総合研究機構, 農業環境研究部門, 主任研究員 (10631054)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 農地景観 / 高次捕食者 / 生息地管理 / ため池 / 栽培体系

Outline of Final Research Achievements

As a measure to conserve biodiversity in 'satoyama' landscapes over a wide area, this study aimed to clarify how the agricultural systems contributes for habitat conservations of gray-faced buzzards, a symbol of 'satoyama' landscapes, in multiple regions belonging to different climatic zones. Our results showed that in the northern Tohoku region, which is the northern limit of the distribution of the buzzards, the rice planting season is slightly later than in the warmer Kanto region, buzzards were tended to breed in farmland with many farm ponds, and frogs are distributed in high densities there. In the north-central Kyushu region, southwest of the range of the buzzards, the rice planting season is one month later than in the Kanto region due to the prevalence of double cropping, and frogs, the main prey species, are rarely found there. Grasslands inhabited by grasshoppers were found to be an important habitat for the buzzards.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

本研究の学術的意義は、高次捕食者であるサシバの生息地選択に対し、気候帯という大スケールの条件だけでなく、 二毛作の有無など栽培体系の地域差が、強く関係していることを解明した点にある。これまでの研究では、高次捕食者の生息地選択の地域差を生じる要因として、気候条件のみが注目されていた。社会的意義は、急速に全国各地に広がりつつある里山保全活動を進める上で、その象徴として重要な役割を担うサシバに象徴される生物多様性の保全を進める上で、二毛作の有無といった栽培体系の違いを組み込む重要性を示した点にある。生物多様性豊かな里山を保全する戦略は、農地の栽培体系の特徴を踏まえた上で策定される必要がある