Influence of Point Environmental Conditions to the Present Species Richness of Fish and Mussel of Floodplain Pools in the Kizu river

Abstract

The Kizu River ecosystem is characterized by lentic habitats such as pools or wando on the floodplain, providing habitats to Acheilognathus bitterlings and freshwater unionid mussels. In the last decade, however, these habitats have been degraded by the decrease in peak discharge and flood frequency and excessive vegetation expansion on the floodplain. In order to restore the suitable habitat structure for the Kizu River ecosystem, it is needed to find out relations of habitat condition required for bitterlings and mussels. We used principal component analysis (PCA) and generalized linear model (GLM) based on selected data by correlation analysis. Species richness of Bitterling was best explained by a model consist of location, age, transparency, mean grain size and DO one year ago. Species richness of mussel was best explained by a model consist of flooding frequency and depth of mud two years ago. Species richness of resident fish was best explained by low relative height, age, area and vegetation coverage and species richness of alien fish was explained by model consist of low relative, area, vegetation coverage and DO. Species richness of resident fish and alien fish were significantly correlated with habitat conditions of current year. The results indicate a range of habitat age for maintenance of fish and mussel diversity including more than two years old, is required in the Kizu River.