小河川の物理的環境構造と魚類の微生息場所

概要

論文の詳細を見る
The physical environment and microhabitat use by fishes were studied in a small stream in northern Hokkaido, Japan. We attempted to examine microhabitat structure in a natural section of the stream with well developed pool-riffle sequences, by comparison with that in a section altered by straightening. Population densities of Oncorhynchus masou masou, Tribolodon ezoe and Noemacheilus toni in the natural section were considerably larger than those in the altered one. Cluster analysis on principal component scores for five microhabitat variables (depth, current velocity, current diversity, substrate and cover) revealed six distinct types of microhabitat in both sections. In the natural section, a regular pattern was recognized for the distribution of these microhabitat types corresponding to the pool-riffle sequences, whereas no such pattern was evident in the altered one. Three out of six microhabitat types which were used selectively by these species constituted a large part of the natural section in comparison with the altered one. The regular distribution pattern of the microhabitat types seemed to provide a preferential feeding habitat, especially for O. masou. Thus, both the distribution pattern and abundance of certain types of microhabitat were considered to be important determinants of habitat quality for stream fishes.
日本生態学会の論文
1994-08-20