FRESH-WATER COMMUNITIES IN THE MARUYAMA RIVER SYSTEM, HYOGO PREFECTURE, I : ECOLOGY OF THE BENTHIC ANIMALS OF THE RIVER YAGI, TORRENTIAL PART OF THE RIVER MARUYAMA (1)

Abstract

1. The River Yagi, the torrential part of the Maruyama River system, may be divided by its river form into two areas, namely upper and lower torrents. Benthic insect communities show two different types in accord with the river forms mentioned above. These are shown in Tables 1 and 2 as well as in Fig. 3. 2. Total standing crops of the main species are very different between the upper and lower torrential areas ; Stenopsycha griseipeknis (Trichoptera) may be responsible principally for this phenomenon. These are shown in Table 3.