Abstract:

During July of 2009, macroinvertebrate assemblages were investigated in Pohe Stream which is an important headwater system belonging to Huanggai Lake waternetwork,located in Chibi County,Hubei Province.A total of 54 taxa were identified,belonging to 4 phyla,6 classes and 36 families.Of which 45 were aquatic insects,4 mollusks,2 crustaceans and 3 others (oligochaete,turbellarian and arachnidan).The larvae of Ephemeroptera and Chironomidae were the dominant groups in abundance.〖WTBX〗Choroterpes〖WTBZ〗 sp.,〖WTBX〗Cinygmula〖WTBZ〗 sp.,〖WTBX〗Baetis〖WTBZ〗 sp.and 〖WTBX〗Ablabesmyia〖WTBZ〗 sp.were most dominant taxa and their relative abundance were 4040%,838%,426% and 419% of the total,respectively.Canonical correspondence analysis (CCA) was used to explore the importance of environmental factors in influencing macroinvertebrate community structure. The results showed altitude and channel width were the significant predictors of the community variance.ShannonWiener diversity and Hilsenhoff's Biotic Index (BI) were explored to assess the water quality of the stream. The results of two indices were different to a certain extent and indicated that the water quality was quite clean in most sampling sections. Considering the coincidence with physical-chemical parameters,BI bioassessment method should be applicable in this headwater stream ecosystem