Abstract
We examined utility of hydraulic flow patterns, subcritical flow, supercritical flow and hydraulic jump for the classification of benthic macroinvertebrates habitats. The measurement of hydraulic parameters and quantitative sampling of benthic macroinvertebrates on stones were conducted in the step-pool reaches of Gunbetsu River in Hokkaido, Japan. Velocities near stone surface differed among the three flow patterns. The abundance of benthic macroinvertebrates on stones was significantly explained with the flow patterns for 75% of dominant species, including mayflies and a caddisfly. The hydraulic flow pattern better explained the abundance on stones for many species than maximum and minimum velocities near stone surface. Our results indicate that the classification of hydraulic flow patterns is useful to understand of macroinverterbrates habitats in step-pool streams.
