Author(s): Xiongdong Zhou; Zhaoyin Wang; Mengzhen Xu; Baozhu Pan; Na Zhao
Keywords: Benthic macroinvertebrate assemblages; Stream power; PerMANOVA; CCA
Abstract: Benthic macroinvertebrates are good indicators to access the aquatic ecological status of rivers. They are influenced by complicated river channel parameters as well as water flow variables, such as substrate composition, flow velocity, water depth, suspended load and channel width. In this study, a physical condition index, stream power P which indicates the energy dissipation in the fluvial process integratedly, was introduced. And the relations between stream power and several biotic variables were analysed quantitatively. Field investigations of macroinvertebrates from 11samples were conducted in April 2014 in the Yarlung Tsangpo River Basin. Altogether 72 taxa of macroinvertebrates belonging to 39 families and 72 genera were identified. Among them were 1 Platyhelminthes, 6 Annelidas, 3 Molluscas and 62 Arthropodas. Taxa richness, density, biomass and Shannon-Wiener diversity index of the 11 samples varied dramatically from 3, 9 ind. ·m-2, 0. 0005g·m-2and 0. 37 to 31, 3472 ind. ·m-2, 3. 3135g·m-2and 0. 71 respectively. Macroinvertebrates of the 11 samples were analyzed using gradient analysis to discuss the main physical conditions influencing benthic assemblages of the Yarlung Tsangpo River Basin. Preliminary findings of this study indicated: the stream power of habitat showed remarkable logarithmic linear relations to taxa richness, density and biomass. Paucity of macroinvertebrates occurred in the habitats of high stream power with fast flow velocity, large sizing substrate and mass bed load transportation.