Ecology, genetics, and beta diversity of zooplankton in "managed floodplain" rice paddies

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06407
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Tohoku University
• Principal Investigator: Makino Wataru 東北大学, 生命科学研究科, 助教 (90372309)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 種多様性 / 微小甲殻類 / 水田 / 耕作方法 / 遺伝子コピー数

Outline of Final Research Achievements

In this study, we 1) examined the possibility that the copy number of ribosomal RNA genes is higher in microcrustaceans in rice paddies than in microcrustaceans in lakes and reservoirs where the period of inundation is relatively long, using the quantitative PCR method, but the results did not support the hypothesis. Furthermore, 2) the possibility that the zooplankton diversity of the entire region increases when there is a mixture of "rice paddies" that differ greatly in the timing of inundation was examined, and the results supported this hypothesis. However, paddy fields that were flooded later in the year had more paddy weeds than those that were not, and the diversity increased as a result of the emergence of microcrustaceans that used the paddy weeds as a substrate. Therefore, it was not possible to distinguish the effect of inundation timing from the effect of paddy weeds.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

本邦を特徴づける里山景観の構成要素である「水田」と「湖沼・ため池」に出現する微小甲殻類（ミジンコ類など）の、生態特性の違いを調べる際に、遺伝子の構造を比較した点が、学術的に新しい試みであった。また水田に、いわゆる「水田雑草」が生えることで、その表面を生活基質とする微小甲殻類（これらは、雑草がない水田には、ほとんど出現しない種である）が卓越することを初めて示した点にも、学術的に大きな意義があると言えよう。