EXTRACTION OF INDICATOR SPECIES TO TEST RESTORATION EFFECTS BY SEDIMENT REPRESNISHMENTS IN DOWNSTREAM REACHES OF DAM

Abstract

To establish indicator species for estimating the effects of sediment replenishment on the downstream ecosystems of dams, we investigated the densities of macroinvertebrates and the factors of river bed compositions at the seven dammed rivers in Kinki region of Japan. Case-bearer and burrower families would be nominated as the indicator species, since their densities were strongly correlated to the river bed condition, especially amounts of fine riverbed materials. Generalized linear mixing models showed that many case-bearer and burrower families were able to approve as the indicator for river bed conditions, and that Glossosoma spp. was the most useful indicator. Such indicator density would provide important information to determine the amounts and frequency of sediment replenishment on the dammed rivers for restoration of downstream ecosystems.