矢作川の上中流域の流水中に生育するコケ植物

Abstract

In the middle reaches of a river, benthic algal community mainly contributes to primary production, because the stream surface is not shaded by riverbank vegetation and sunlight reaches the riverbed. Several studies showed that stable riverbeds with fewer sediment movements trigger changes in the structure and quantity of benthic algae community (Biggs 1996) . In such conditions, bryophytes have been reported to grow densely (Muotka & Virtani 1995;Aquatic bryophytes, as well as benthic algae, affect the habitats of benthic animal communities and food resources for fish (Stream Bryophyte Group 1999) . Studies on the spatial distribution of aquatic bryophytes in the river are thus necessary to clarify the functions of river ecosystems. Ecology of aquatic bryophytes have mostly been studied in streams with small mountainous catchments and in the middle-reaches of rivers with small catchment areas