Study On The Relationship Between The Dynamic Characteristics Of Zooplankton Community Structure And Water Environmental Factors Of The XiangJiang River In Changsha

This research,focusing on the temporal and spatial dynamic of zooplankton species composition,density,biomass,dominant species and diversity,exploring the relationship between the zooplankton community structure and water environmental factors,combining the physical and chemical index and biological index to evaluate water quality,was to provide scientific reference for water environment monitoring management of the Xiangjiang River in Changsha.Ecological investigations had been conducted on zooplankton and water environmental factors at 12 sites during January to November in 2016.Pearson Correlation Analysis,Multiple Stepwise Regression Analysis and Redundancy Analysis were applied.The main research results were as follows:1.A total of 127 species belonging to 76 genera were identified,among which,63 species of 28 genera were Rotifera?49.61%of total?,42 species of 34 genera were Protozoa?33.07%?,12 species of 6 genera were Cladocera?9.45%?and 10 species of 8 genera?7.87%?were Copepoda.Rotifera and Protozoa were dominant in the species composition.The difference of the seasonal and spatial changes of species composition were significant?P<0.05?.In terms of seasonal cha-nges,the maximum of species number of zooplankton occurred in summer,and the minimum occurred in winter.In terms of spatial chang-es,the maximum of species number of zooplankton occurred in Orange Island,and the minimum occurred in Zhushuqiao.2.The density of zooplankton of the Xiangjiang River in Changsha varied from 24 ind/L to 651 ind/L.The average of density was 142 ind/L.The biomass of zooplankton varied from 0.08mg/L to 7.03mg/L.The average of biomass was 0.38mg/L.Protozoa and Rotifera were dominant in the density,accounting for 59.76%and 23.30%of the total density respectively.Copepoda was dominant in the biomass,accounting for81.71%of the total biomass.The difference of the seasonal changes of density was significant?P<0.05?.The difference of the spatial changes of density was not significant?P>0.05?,meanwhile,the seasonal and spatial changes of biomass were not significant?P>0.05?.In terms of s-easonal changes,the density of zooplankton was high in spring and summer,and was low in autumn and winter.The biomass of zooplankton was rising from January to November.In terms of spatial changes,the density and biomass of zooplankton were high in the samples nearing the estuary,and were low in Zhushuqiao.3.There were fifteen dominant species of the Xiangjiang River in Changsha:Difflugia globulos,Aspidisca costata,Centorpyxis aerophilaw,Stribilidium gyrans,Tintinnopsis sinensis,Asplachna priodonta,Asplanchna brigthwelli,Brachionus angularis,Keratella cochlearis,Bosmina longirostris,Diaphanosoma brachyurum,Chydorus ovaliskurz,Thermocyclops brevifurcatus,Thermocyclops hyalinus and Eucyclops speratus.4.The Shannon-Weiner index varied from 0.79³.63,Margalef index and Pielou index varied from 1.13⁷.73 and 0.40¹ respectively.The difference of the seasonal changes of Shannon-Weiner index,Margalef index and Pielou index were significant?P<0.05?,spatial changes of three kinds of diversity index were not significant?P>0.05?.In terms of seasonal changes,the diversities of zooplankton were high in summer,and were low in spring and winter.In terms of spatial changes,the diversities of zooplankton in the middle and upper reaches were higher than in lower reaches,meanwhile,the diversities of zooplankton in the trunk stream were higher than in tributaries.5.Through the Correlation Analysis of species-environmental factors,the crop of Rotifera,Shannon-Weiner index and Margalef index were significantly and positively correlated with temperature?P<0.05?.The crop of Cladocera and Copepoda were significantly and positively correlated with NH₃-N?P<0.05?.The crop of protozoa was not significantly correlated with any water environmental factors?P>0.05?.Through the Multiple Regression Analysis,NH₃-N was the most key water environmental factors to the community structure of zooplankton of the Xiangjiang River in Changsha.The rise of pH value had inhibitory effect on zooplankton crop.Redundancy Analysis indicated that TP,NH₃-N,COD,Cu and Pb were main water environmental factors to the community structure of zooplankton of the Xiangjiang River in Changsha.Halteria grandinella and Aspidisca costata favored high nutrient.Dileptus amphileptoides,Thermocyclops hyalinus,Tintinnopsis sinensis and Mastigella vitrea were most suitable for low nutrient.Keratella cochlearis,Difflugia globulosa,Diaphanosoma brachyurum,Centorpyxis aculeate and Bosmina longirostris were tolerant to heavy metal.6.The water quality of the Xiangjiang River in Changsha was at mild to moderate pollution status according to the physical and chemical index and biological index in 2016.The water quality was between national standard case?and national standard case ?.