Abstract: To study the seasonal dynamics of macrozoobenthos community in Xiangxi River, the individuals of macrozoobenthos in the River were quantitatively moni tored. A total of 197 taxa belonging to 6 class and 68 families were collected, among which, Baetis spp., Epeorus spp., and Nemoura spp. were the do minant group s, and their compositions varied with seasons. The macrozoobenthos community was most complicated in winter, followed by in spring and autumn, and the simplest in summer. Gather-collector was the main component of functional feeding groups in Xiangxi River system, followed by scraper, predator, and filter-collector, while shredder only accounted for a small part. Canonical correspondence analysi s showed that the factors affecting the macrozoobenthos community were dissimila r among seasons. In summer and autumn, nutrients had greater effects; and in all seasons, water depth had definite effects.

Key words: Meretrix meretrix, biomarker, integrated biomarker response index, environmental stress.