| Biological community and ecosystem function of rivers are largely governed by hydrogeomorphic characteristics of rivers that are structured hierarchically in temporal-spatial scales (Frissel et al. 1986). Although organisms often respond to physical environments that vary in small spatial scales (i.e., patch and habitat scale), range, frequency and combinations of physical variables within an area are determined by hydrogeomorphic features of large spatial scales (reach, segment and watershded scales). Understanding physical-biological relations at large spatial scales are necessary when predicting distributions of biological communities in broad spatial scales, but knowledge is still lacking to make general patterns at those scales. Our main purposes in this study were to clarify longitudinal distribution patterns of flow, substrates and benthic marcoinvertebrate communitis, and examine physical-biological relations at segment scale. For difficulties in covering whole area of river landscapes, we focused here on riffles, which often posses high benthic biomass. |
