SPATIAL AND TEMPORAL VARIATION OF MACRO-INVERTEBRATE FUNCTIONAL FEEDING GROUPS ABUDANCE IN RELATION TO HYDRO-ENVIRONMENTAL FACTORS IN A SBUTROPICAL KAST RIVER, CHINA

Our study evaluated the effects of spatial and seasonal variation on the structure of the macroinvertebrate functional feeding groups abundance in a subtropics river in China. Sampling was performed during the dry (October 2009) and wet (April 2010) period, characterizing flow, physical and chemical conditions were analyzed for each sample in three reaches located in upstream, middle stream and downstream. The result showed that predator, scraper and collector-gathers abundance increased in wet period in all three reaches; Shredder and collector-filter abundance decreased in wet period both upstream and midstream, but increased in downstream. Shredders abundance in dry period(decreasing) and in wet period(increasing) from upstream to downstream; Collector-filter had similar abundance in dry period, but the abundance of downstream was higher than upstream and midstream in wet period; Scraper abundance were much lower in upstream than midstream and downstream in both season; Predator abundance increased in both season from upstream to downstream. The distribution of dominant species can better explain the variation of FFGs. After Canonical correspondence analysis (CCA), eight variables(substratum type (cobble, pebble), velocity, total nitrogen, salinity, water temperature, aquatic plant, turbidity) governed the community structure variance.