東京都内におけるユスリカの生態 II. : 善福寺川におけるユスリカ幼虫の分布

抄録

Seasonal distributions of chironomid larvae were studied in the Zempukuji River from April 1976 through February 1977. Chironomus yoshimatsui was dominant in the upper region of the river, and Cricotopus bicinctus was generally dominant in the lower region. Habitat conditions of the upper region were characterized by weak water flow, muddy substratum, dense growth of aquatic macrophytes, and severe oxygen deficiency at night. On the other hand, the lower region of the river was characterized by a faster water flow, embedded pebble and loose cobble bottom, and less severe oxygen deficiency. BOD, pH, and nutritive salt (N, P) levels of the water were not significantly different between the two regions. The distribution and abundance of the two species of chironomid larvae seemed to depend on the degree of oxygen depletion in the river.