木津川の聖牛周辺に形成される一時的たまりの生息場特性

Abstract

In order to maintain habitat heterogeneity in the Kizu River, we focused on one of the Japanese traditional river works "Seigyu" as a technique to control riverbed erosion and deposition. We made a series of field monitoring of geomorphological and habitat changes after the installation of groups of Seigyu at a bankside of a sand bar. The upstream and offshore side of the Seigyu were highly eroded while the downstream side was highly deposited after each of several floods in these 2years. As a consequence, temporary ponds were formed at the side and in front of the Seigyu although there were few ponds before the Seigyu installation. Results of biological monitoring showed that the ponds functioned as habitats for aquatic animals of still water inhabitants and rarely for those of running water inhabitants. These results indicate that Seigyu has a high potential as a device of riverbed management for facilitating local erosion and deposition to keep habitat and biological diversity in rivers.