灌漑システムおよび農法の違いが水田水域における食物連鎖に及ぼす影響

―安定同位体比を用いた水田水域の食物連鎖構造の解析に向けた検討―

抄録

For the purpose of examining on role of irrigation and cultivation system to paddy ecosystem, we study species and number of Odonata larvae and analyze the stable isotope ratios of the Odonata larvae and the plankton/detritus in water of paddy fields and irrigation ponds. As a results, cultivation system clearly effects to composition of species and number of Odonata larvae. δ ¹³C indicates that Orthetrum albistylum speciosum larvae and Coenagrionidae spp. larvae which are dominant species in paddy water, depend on specified food sources, each other. δ ¹⁵N shows that the trophic level of Odonata larvae is higher than that of the plankton/detritus in paddy water. It is considered that analyze the stable isotope ratios application is effective to examine water ecosystem and food web in paddy.