Benthos composition of a hill stream in Western Himalayas

Abstract

Among the macro-invertebrates of Sheerkhad stream, the nymphs of mayflies emerged as the dominant group (40-67%) reaching their highest population during summer months, whereas the larvae of caddis flies (33·65%) dominated the winter crops of the aquatic insects, showing their aptitude to the cold-water temperatures. The peripbytic communities were constituted by diatoms (77·68%), green and filamentous algae (12,73%) and blue-green algae (9·39%) with the highest densities during spring months when stream water was slightly warmer with increased length of day light. Due to the detrimental effect of flood the densities of benthic organisms were found to be low during the monsoon months.