| To evaluate the lavels of water pollution of Weihe River basin and provide the basicbiological data support for the rive pollution treatment, the Community structure ofzooplankton in Weihe River basin was investigated for2times in2012October (wet season)and2011April (dry season). The survey sampling sites have60,and the32sample sites wereset in the Weihe River system, the15sample sites were set in the Jing River system, the13sample sites were set in the North Luo River system. The species composition, density,biomass，temporal and spatial variation, dominant species composition，biodiversity anddistribution of zooplankton were investigated and the water quality was evaluated. The resultsin this study showed that:1.114species of zooplankton were identified in Weihe River basin, including82species ofrotifera,14species of protozoa,14species of cladocera and4species of copepods, the rotiferaccounted for71.93%,the protozoa accounted for12.28%,the cladocera and copepods accountedfor12.28%and3.51%respectively. Temporal and Spatial changes in the community structure ofzooplankton were obvious. Rotifers was dominant in the species composition and was mainlyspecies in three River and the two seasons.67species of zooplankton were identified in JingRiver system.59species of zooplankton were identified in North Luo River system.97species ofzooplankton were identified in Weihe River system.76species of zooplankton were identified inwet season in Weihe River basin,85species of zooplankton were identified in dry season inWeihe River basin. The number of species change as: wet season <dry season in Jing Riversystem and the Weihe River system, the difference was not significant (P>0.05) The number ofspecies change as: wet season> dry season in North Luo River system, the difference wassignificant (P <0.05). The number of species change as: trunk stream>tributary, upstream>downstream.2. The average density of zooplankton was64.08ind./L and the average biomass ofzooplankton was0.089mg/L in Weihe River basin, and they change as:wet season <dry season,and the difference of temporal and spatial distribution were significant. The average density ofzooplankton was30.00ind./L and the average biomass of zooplankton was0.058mg/L in JingRiver system, and the difference in the season was significant. The spatial distribution change as:upstream> downstream in wet season, upstream <downstream in dry season. The averagedensity of zooplankton was42.45ind./L and the average biomass of zooplankton was0.213mg/Lin North Luo River system, and the difference in the season was not significant. The spatialdistribution change as: upstream> downstream, tributary junction> tributary. The averagedensity of zooplankton was88.75ind./L and the average biomass of zooplankton was0.115mg/L in Weihe River system, and their difference in the season were not significant and the spatialdistribution change as: upstream <downstream, trunk stream> tributary. In Weihe River basinthe temporal and spatial change in the dominant species of zooplankton were obvious, Therewere5same dominant species of zooplankton in two season in Jing River system,3dominantspecies were common in North Luo River system, and2dominant species were commoninWeihe River system, most of which were rotifers.3. In Weihe River basin, the average of Shannon-Weiner species diversity index(H) was2.60, Margalef species richness index (M) and Evenness index (J) were1.58and0.79respectively, and the difference of temporal and spatial distribution were significant. In JingRiver system, the average of Shannon-Weiner species diversity index was2.52, Margalefspecies richness index was1.86, and Evenness index was0.80. In North Luo River system, theaverage of Shannon-Weiner species diversity index was2.66, Margalef species richness indexwas1.27, and Evenness index was0.82.In Weihe River system, the average ofShannon-Wieaver species diversity index was2.61, Margalef species richness index was1.58,Evenness index was0.78. On the basis of diversity index, The water quality of the Weihe riverbasin has been moderate eutrophication and water has been polluted moderately.4. Through the canonical correspondence analysis(CCA) of species-environmentalrelationships, the environmental factors driving zooplankton community structure weredifferent in Weihe River basin. totally of6notable affect zooplankton communityenvironmental parameters were checked out in wet season, they were Altitude(p=0.001),Channel width(p=0.007), water temperature(p=0.003), phytoplankton (p=0.004), Saturability(p=0.048)and nitrite (p=0.006). totally of5notable affect zooplankton communityenvironmental parameters were checked out in dry season, they were Altitude(p=0.001),phytoplankton (p=0.004), Suspended solid (p=0.002), Salinity(p=0.030) and nitrite(p=0.029).5. According to CCA analysis, In Weihe River basin, some environmental factors drivingzooplankton community structure have been traced back, they were affected greatly by thenatural environment factors, but the impact of human activity could not be ignored. |
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