Clarification of the mechanism of phenological mismatch and its impacts on pollination systems

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07551
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Hokkaido University
• Principal Investigator: Kudo Gaku 北海道大学, 地球環境科学研究院, 准教授 (30221930)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 気候変動 / フェノロジー / 送粉系 / 生物間相互作用 / 高山生態系 / ポリネーター

Outline of Final Research Achievements

The mechanism of phenological mismatch between spring ephemeral and overwintered bumble bees was revealed based on the long-term monitoring and the snow removal experiment in a deciduous forest. Flowering onset was explained with surface thermal degree-days after snowmelt, while bee emergence was determined by soil temperature. Phenological mismatch in early spring occurred when snow melted early but subsequent soil warming progressed slowly. Seed-set success of plants was strongly related to the extent of mismatch.
In the alpine ecosystem, flowering period of snowbed communities highly varied from year to year reflecting the fluctuation of snowmelt time. However, seasonal dynamics of bees were more conservative. Mismatch occurred in early-snowmelt summer in which flowering progressed rapidly and bee populations increased after the major flowering period. In both cases, therefore, acceleration of flowering phenology more than bee phenology is a major cause of mismatch.

Free Research Field

植物生態学、気候変動生態学、送粉系生態学

Academic Significance and Societal Importance of the Research Achievements

地球温暖化が生態系に及ぼす影響のひとつに、生物の季節性攪乱がある。様々な生物でフェノロジーの早期化が報告されてきたが、それが生態機能に及ぼす影響については不明点が多かった。最も重要な生態系サービスのひとつである送粉機能は、ポリネーターと植物の季節的ミスマッチにより低下する。本研究では、寒冷圏生態系の重要なポリネーターであるマルハナバチに受粉を依存している北方林の春植物と高山植物を対象にして、温暖気候下で両者にミスマッチが起きることを実証し、その発生メカニズムを解明することができた。この成果は学術的な意義に留まらず、気候変動が生態系に及ぼす影響を広く社会に伝えるメッセージになると期待される。