水田湛水中のドブシジミ（マルスダレガイ目：ドブシジミ科）とドジョウ（コイ目：ドジョウ科）が両種の餌増加に及ぼす間接効果とその種間相互作用が2種の分布連関に与える影響

抄録

Although biological interactions have been studied intensively to account for population dynamics and community structure, little is known of the aquatic organisms that inhabit paddy fields, despite their high biodiversity. We conducted field research and an experiment to elucidate direct and indirect interactions among micro- and filamentous algae, their consumers（fingernail clams and water fleas consume the former and chironomids the latter）, and loaches that prey on water fleas and chironomids. The experiment examined the effects loaches and fingernail clams have on algae biomass. Fingernail clams reduced microalgae biomass by filter feeding, while loaches increased it by feeding on water fleas. Loach predation on water fleas increased the biomass of microalgae indirectly, which might have led to an increased density of fingernail clams. Filter feeding on microalgae by fingernail clams increased the density of filamentous algae, a potential competitor of microalgae, suggesting that fingernail clams increase the density of chironomids by enhancing their diet, which may then increase the density of the loaches that prey on chironomids. Field research revealed a positive spatial association between loaches and fingernail clams, attributable to their mutual food resource facilitation.