Evaluation of biodiversity in the head of 'Yatsu' small valleys in Kanto plain

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K11730
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64040:Social-ecological systems-related
• Research Institution: National Institute for Environmental Studies (2019-2020); Toho University (2018)
• Principal Investigator: Nishihiro Jun 国立研究開発法人国立環境研究所, 気候変動適応センター, 室長 (60334330)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 湧水 / 谷津 / 湿地 / 生物多様性

Outline of Final Research Achievements

‘Yatsu’, small valleys that occur at the edge of plateaus, were evaluated as habitat of spring-dependent species. These valleys were found to be an important habitat for many endangered species. It was suggested that the amount of spring water discharge that supports the biota in the valleys is influenced by the land use of the catchment area. As the rainwater impermeable surface on the terrace decreases due to urbanization, the amount of spring water will decrease and become depleted. We also investigated the habitat use of Lethenteron reissneri, one of the spring-dependent species. It was suggested that it maintains its population by moving seasonally within the river channel. Depletion of spring water and fragmentation of rivers due to urbanization can be a threat to populations of the spring-dependent species inhabiting Yatsu habitat.

Free Research Field

保全生態学

Academic Significance and Societal Importance of the Research Achievements

「谷津」はかつては農地として利用されていたが、現在では耕作放棄地となっている場合が多い。本研究の結果は耕作放棄地でも、絶滅危惧種を含む多様な生物のハビタットとして重要であることが示された。また谷津が生物のハビタットとして機能するためには湧水の存在が重要である。湧水の維持のためには集水域の土地利用が重要であり、集水域の都市化は湧水の枯渇を招きうることが示唆された。生物多様性保全のためには、局所環境だけでなく景観スケールでの検討が重要である。