Abstract
We investigated about an inhabitation of Coenagrionidae on a Ludwigia peploidea Raven ssp. stipulacea Raven community, which is a vulnerable species locally distributed on Kashio River in east Kanagawa. As a result, it was shown clearly that three species, Ischnura senegalensis Rambur, I. asiatica Brauer and Cercion hieroglyphicum Brauer, dominated on this river, and the abundance peaks of each species differed from spring to autumn. Since Coenagrionidae was hardly recorded in a neighboring river, it was proved that the large number of its habitation in Kashio River was exceptional. Especially, C. hieroglyphicum and I. asiatica indicated high abundance among distribution of L. peploidea ssp. stipulacea. Data for larva investigation indicated that the larva density was high in sites on the slower stream. This observation suggests that L. peploidea ssp. stipulacea community inhabited on waterside plays a key role in formation of microhabitats for larva. Data for mark-recapture investigation indicated that the max distance of immigration was about 700 m, and nearly all of recapture individuals stayed on the identical sandbar. To design an arrangement of L. peploidea ssp. stipulacea community at intervals of some hundred meters, it was inferred that this Kashio River function as an ecological corridor for Coenagrionidae in urban area.
