Abstract
Relationship between bank vegetation and environmental factors were investigated in lower reach of Chino River, Kushima, southern Kyushu in order to provide basic information for restoration of natural vegetation after river construction work. Plant species composition of 37 quadrats placed on different physiognomy and topography were classified into four vegetation types by TWINSPAN. Close relationship between the four vegetation types and physical environments were detected by ANOVA, indicating a certain level of vegetation differentiation according to their site condition within a river bank. However, comparison with the natural vegetation along the similar river reported in the previous studies suggested that the vegetation of the studied reach was not fully differentiated due to the lack of intermediate conditions of micro-topography and soil moisture between dry sites on upper banks and wet sites on riverbed sediments. Among the studied site, concave slopes on the bank showed the intermediate soil condition in terms of soil hardiness and EC. We concluded that the studied vegetation of the Chino River had less diverse structure compared to the natural vegetation. We suggest that the restoration of current vegetation structure after river construction is minimum requirement, and that formation of the intermediate site condition such as concave bank slopes are desired to enrich the restored vegetation on the new channel bank.
