Elucidation of the actual impact of sea-level rise on mangrove ecosystems at the community level and prediction for the near future

2022 Fiscal Year Final Research Report

• Project/Area Number: 17H02034
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geography
• Research Institution: Nanzan University
• Principal Investigator: Fujimoto Kiyoshi 南山大学, 総合政策学部, 教授 (50329752)
• Co-Investigator(Kenkyū-buntansha): 渡辺 信 琉球大学, 熱帯生物圏研究センター, 准教授 (10396608) ; 小野 賢二 国立研究開発法人森林研究・整備機構, 森林総合研究所, 主任研究員 等 (30353634)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: マングローブ林 / 海面上昇 / 表層侵食 / 土砂フラックス

Outline of Final Research Achievements

To clarify the effects of sea-level rise on mangrove ecosystems at the community level and to make future projections, we conducted field research on Pohnpei Island, Federated States of Micronesia, where sea-level rise has been pronounced in a humid tropics, and on Iriomote Island, a subtropics where sea-level rise has been comparable to the global mean. The results indicated that in the Bruguiera gymnorrhiza community, where the density of Rhizophora species has decreased, erosion on the forest floor and increased flux during flooding and drainage may cause sediment discharge, resulting in annual erosion on the order of several centimeters per 10 cm of sea level rise. On the other hand, it was confirmed that the Rhizophora community can maintain its location by accumulating mangrove peat in response to a sea-level rise of 5 to 8 mm per year.

Free Research Field

自然地理学

Academic Significance and Societal Importance of the Research Achievements

マングローブ生態系における海面上昇の影響実態を明らかにすることで、その危険性に対して改めて警鐘を鳴らすと共に、その影響を群落レベルで評価することにより、熱帯・亜熱帯地域における海面上昇下での沿岸環境保全策を構築するにあたって、マングローブ林保全や植林を活用する際の科学的根拠を与えることができる。