Geomorphic development and vegetation change of the wetlands in the Sarufutsu River valley in northern Hokkaido, Japan

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H02956
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geography
• Research Institution: Hokkaido University
• Principal Investigator: FUJITA Hiroko 北海道大学, 北方生物圏フィールド科学センター, 教授 (50202289)
• Co-Investigator(Kenkyū-buntansha): 百原 新 千葉大学, 大学院園芸学研究科, 教授 (00250150) ; 井上 京 北海道大学, 農学研究院, 教授 (30203235) ; 紀藤 典夫 北海道教育大学, 教育学部, 教授 (30214836) ; 近藤 玲介 皇學館大学, 教育開発センター, 准教授 (30409437)
• Research Collaborator: SAGAYA Tsumoru ; SHIGENO Kiyoyuki ; YOKOTA Akihiro ; KATO Yukie ; SAKAMOTO Tatsuhiko
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 植生変遷 / 花粉分析 / ルミネッセンス年代測定 / AMSI4C年代測定 / 地形 / 堆積物 / 大型植物遺体 / 海水準変動

Outline of Final Research Achievements

This study aimed to elucidate the relationship between the formation of the wetlands in the Sarufutsu River valley with geomorphic development, sea-level change, and climate change. In addition to stratigraphic analysis, dating, analysis of plant macrofossil assemblages, pollen analysis, diatom analysis, etc. have been done from the core samples that were acquired by mechanical and manual drilling at the Sarufutsu River wetlands.
During the Jomon transgression seawater intruded into the middle to downstream of the valley but it didn't influence the upstream. But even in the upstream area, the formation of the wetlands started since the decline of sea level. This fact suggested that the climatic conditions during the period of coastline regression worked favorably for the wetland formation. The Naka-Shitsugen started the formation of present-type wetland vegetation from 2.4 ka. Maruyama Shitsugen and Kamisarufutu Nishi Shitsugen also started similar formation after 1.3 ka.

Free Research Field

植物生態学