Abstract:

With the rapid development of economy, most watershed ecosystems have suffered serious human disturbance, leading to the severe degradation of ecosystem services and loss of species diversity. The Qingyi River, located in the south of Anhui Province, is the largest tributary of the lower Yangtze River. In order to fully understand the present status of macrozoobenthos community in the Qingyi River basin, a field investigation was conducted in different order streams in August 2013. The results showed that total species number was 60, belonging to 39 families and 58 genera. From first to fourth order streams, the species number decreased gradually, and was 46, 39, 36 and 16, respectively. The dominant group was aquatic insects in first to third order streams, and molluscs in fourth order stream. The density and biomass of macrozoobenthos in the Qingyi River basin was 382 ind./m2 and 3643 g/m2, respectively. The density was highest in second order stream, and lowest in fourth order stream. The biomass of second and fourth order streams was significantly higher than that of the first order stream. In terms of functional feeding groups, scrapers and collectorfilterers dominated the Qingyi River basin. Relative density and relative biomass of scrapers firstly increased and then decreased with the increase of stream order; shredders had high proportion in the first and second order streams, while the collectorgatherers and collectorfilters had high proportion in the first and fourth order streams