The Kizu River ecosystem is characterized by lentic habitats such as pools and wando on the floodplain, providing habitats to bitterlings and mussels. However, these habitat conditions have been degraded by reduction of connectivity with main channels. In order to restore the Kizu River ecosystem, it is necessary to understand relations between habitat conditions and diversity of species. This paper aims to show appropriate channel conditions for bitterling and mussels as their habitats using aerial photos and field survey data.

Suitability index (SI) of bitterling and mussels were analyzed in relations with habitat conditions (flooding frequency, physical parameters and water quality) from 2007 to 2011. In addition, geomorphic characteristics of floodplain located the habitats also were analyzed as parameters of habitat conditions. These parameters consisted of channel width, the number of channels, sinuosity, floodplain vertical shape index (FVSI; >0 concave, =0 straight, <0 convex) and landscape composition.

The SI of mussels resulted in the maximum values under flood frequency between 8 and 22 day/year. These suitable habitats significantly increased in number under FVSI between -0.2 and 0.