Community Structure And Influencing Factors Of Metazoan Zooplankton In Four Typical Habitats Along Rivers And Lakes In Anhui

Anhui is a province with warm and humid climate,numerous water bodies and abudant macrophyte species.Among them,Wuchang Lake,Shengjin Lake,Jinbao Dike,Yanwo Dike,Wuchang Lake macrophyte restorated demonstration project area,and fish pond are Anhui lakes and ponds that are geographically close to each other,but have different nutrient concentrations and macrophyte coverage.This article divides the above water bodies into open water habitats(Wuchang Lake and Shengjin Lake),submerged macrophyte habitats(Jinbao Dike),emergent marophyte habitats(Yanwo Dike,Wuchang Lake macrophyte restoration demonstration project area),fish pond(the artificial fish pond)according to the area and shape of water body in four typical habitats,as well as different nutrient concentrations,macrophyte habitat parameters.And from April 2018 to January 2019,the four typical habitats were investigated to study the spatial and temporal distribution of metazoan zooplankton community structure,dominant species and their density in the four typical habitats,and analyzed the relationship using CCA Correlation between community structure and environmental factors.The results were as follows:1.A total of 63 species of 39 genera and 20 phyta were identified in the four typical habitats.There were 33 species of 16 genera and 8 phyta of rotifers,18 species of 11 genera and 6 phyta of cladocera,12 species of 6 phyta and 11 genera of copepods.There were the most species in summer which were 51 species,instantly the least species in winter which were 29 species.In each season and total species,the number of rotifers was the largest,and the number of cladocera and copepods was relatively less.2.The average annual density of metazoan zooplankton in four typical habitats was 455.41 ind./L overall,rotifers accounted for 87.4% and 398.18 ind./L,cladocera accounted for 6.7% and 30.38 ind./L;copecods accounted for 5.9% and 26.85 ind./L.The seasonal variation trend of the average metazoan zooplankton density was:autumn>spring> winter> summer.The spatial change trend was: fish pond habitat>submerged macrophyte habitats> emergent macrophyte habitats> open water habitats.3.The average annual biomass of metazoan zooplankton in four typical habitats was 390.39 mg/L.From the seasonal point of view,the total biomass in winter was the highest,which was 240 ± 134 mg/L;the total biomass in autumn was the lowest,which was 14.33 ± 6.77 mg/L.Copecods accounted for the highest proportion in spring and autumn,with 95.7% and 87.4% respectively;while the cladocera had the highest proportion in summer and winter seasons,were 66.23% and 97.63%respectively.The proportion of rotifers in each season was low.The seasonal change trend of zooplankton biomass in four typical habitats was winter> summer> spring>autumn.The spatial change trend was: fish pond habitat> submerged macrophyte habitats> emergent macrophyte habitats> open water habitats.4.The seasonal variation range of Shannon-Wiener(H`)diversity index for zooplankton in four typical habitats was: 2.04~2.87.The seasonal variation range of Pielou(J`)diversity index was: 1.31~3.01.The seasonal variation range of Marglef(D`)richness and diversity index was: 0.63~0.76.The Shannon-Wiener diversity index had the same seasonal and spatial change trend as the Marglef richness diversity index,both were summer> spring> winter> autumn,and open water habitats>submerged macrophyte habitats> emergent macrophyte habitats> fish pond habitat.The spatial and seasonal trend of Pielou diversity index was spring> summer>winter> autumn,open water habitats> emergent macrophyte habitats> submerged macroohyte habitats> fish pond habitat.5.The physical and chemical factors of four typical habitats also had significant changes in season and space.The results showed that the water temperature had obvious seasonal changes,reaching a peak in summer(2018.7),which was32.37±0.56℃,and reaching a minimum value in winter(2019.1),which was6.7±0.74℃.The turbidity reached the maximum value in spring,62.3±65.9 NTU,and reached the minimum value in winter,35.5±31 NTU.From the perspective of space,the transparency of the open waters was 0.60±0.19 m,which was significantly higher than other habitats(P<0.05).The TP concentration in fish pond was significantly higher than other habitats,at 0.33±0.05 mg / L,and the lowest in open waters was only0.06 ± 0.03mg/L;the conductivity reached a maximum of 218±49.6 μs/cm in fish pond habitat,and reached the lowest was only 88.4±19.1μs/cm.Pearson correlation analysis and redundant analysis(RDA)results showed that environmental factors such as water temperature,transparency,turbidity,chlorophyll a,pH,and nutrients were closely related to the seasonal and spatial dynamic changes of the metazoan zooplankton community structure in four typical habitats(P<0.05).In this paper,metazoan zooplankton was regarded as the research object to explore the differences in metazoan zooplankton community composition and its population dynamics in four typical habitats composed of different nutrients and different marophyte,to found out the key factors that affected the metazoan zooplankton community structure,it also provides the necessary scientific basis for environmental management and ecological resource protection of different water bodies in Anhui Province.