Direct impacts of Procambrus clarkii on rare plant and animal species

Research Project

Project/Area Number	16K18481
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Conservation of biological resources
Research Institution	Niigata University
Principal Investigator	Kishimoto Keiko 新潟大学, 研究推進機構, 准教授 (80525692)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000) Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000) Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywords	侵略的外来生物種 / DNAバーコーディング / アメリカザリガニ / 捕食－被食関係 / 捕食-被食関係 / 侵略的外来生物 / 胃内容物分析 / 希少種 / 侵略的外来種 / 在来種保全
Outline of Final Research Achievements	Our diet analysis on Procambarus clarkii by direct observing indicated that most of the individuals rely　on the plant materials in the study site. DNA barcoding analysis suggests that the crayfish species feed on six plant families, spiders, and 4 insect orders. According to our diet analysis by DNA barcoding, rare species of aquatic animals was not detected. In addition, the proportion of the plant materials detected in the crayfish guts tended to be high for the most of the individuals. Thus, it is unlikely that the crayfish species have great impacts on the rare aquatic animal species by direct feeding in the man-made ponds of our study site. However, our study suggested that the host plants that rare aquatic animal species oviposit are included in the plant materials detected by DNA barcoding analysis. There is a possibility that the crayfish species indirectly impact on the rare aquatic animals through not only cutting plants but also directly feeding the host plants.
Academic Significance and Societal Importance of the Research Achievements	生物間相互作用を無視した外来種駆除によって新たな問題が生じる可能性が指摘されているが、駆除前に捕食－被食関係を把握するのは難しい。本研究は、DNAバーコーディングが雑食性のアメリカザリガニの餌生物をある程度絞込める有効な手法であることを示した一方で、共食いが多く、ブロッキングプライマーを用いた手法では食物網解明が難しいこともわかった。また、本研究では、より正確に種レベルで餌生物を同定するために、対象地域の希少種を含む動植物の網羅的なデータ整備を行った。データベースは将来の研究への活用と、在来種保全や遺伝子資源の保全など生物資源保全への貢献が期待される。