Study On The Characteristics Of Community Structure Of Protozoa, Lhasa Lhalu Wetland National Nature Reserve, Tibet

During the period of July2009to August2012, five sampling sites were chosenat the National Nature Reserve area of Lhalu wetland，Tibet. Water and soil sampleswere collected with stratification method in summer and autumn respectively, speciesdiversity and community characteristics of the Protozoa was studied with in vivoculture and fixed-staining methods; the environmental quality of the wetland wasevaluated according to major environmental factors primarily and main results arefollowing:(1) Species diversity of the Protozoa: identified255species of Protozoa fromfive sampling sites in total. There were145species of Sarcomastigophora, whichaccounting for56.86%of the total species, discovered42species are new records forthe Tibetan Autonomous Region and, it accounted for28.9%of theSarcomastigophora.110species were found for the Ciliophora which accounting for43.14%of the total number of species. Among them28species are new records forthe Tibetan Autonomous Region and that also accounting for25.5%of total numberof species of the Ciliophora. The result showed that Lhalu wetland had high speciesrichness of Protozoa.(2) Characteristics of community structure: Identified225species of Protozoa intotal, belonging to3subphylum,8classes,28orders,79families and113genera.There were145species in the Sarcomastigophora, belonging to2subphylum,5classes,15orders,35families and60genera. Among them, there were49species inthe subphylum of the Flagellum which accounting for33.79%of total number ofspecies. There were96species in the Sarcodina and it accounting for66.21%of thetotal number of species. The Arcellinida was the dominant group within the Phylumof the Sarcomastigophora, it accounted for30.3%of number of species of theSarcodina. Both Amoebida and Euglenida were sub-dominant groups, accounting for19.3%and17.2%of the Sarcomastigophora separately. Chloromonadida, Volvcales,Cercomonadida and Monothalamia were occasional groups, each of them accountingfor0.69%of the total number of species of the Sarcomastigophora. All other orderswere belonging to common groups. Discovered28species which were new recordsfor the Tibetan Autonomous Region, and that accounted for28.9%of the total number of species of the Sarcomastigophora.There were110species for the Ciliophora, they were belonging to3classes,13orders,44families and53genera. There were48species of Kinetofragminophoreawhich was accounting for43.6%of total number of species of the Ciliophora; andfound34species of Polymenophorea, it was also accounting for30.9%of totalnumber species of the Ciliophora.28species recorded for the Oligohymenophoreaand that accounting for25.4%of total number of species of the Ciliophora. Both theHypotrichida and the Prostomatida were dominant groups, each of them accountingfor21.8%and19.1%of total number of species of the Ciliophora. TheScuticociliatida, Cyrtophorida and Hymenostomatida were belonging to sub-dominantgroups and were accounting for10%,10%and9.09%respectively. All other orderswere common groups.28species found as new records for the Tibetan autonomousregion which accounting for25.5%of total number of species of the Ciliophora. Theresult shows that the Lhalu wetland has complicated community structure of Protozoa.(3) Dominant species are including Centropyxis discoides, Cryptomonas. Ovata,Cryptomonas. Erosa, Gymnodinium aeruginosum, Trachelomonas lacustris,Glenodinium pulvisculus, Coleps hirtus, C. Margaritaceum and Strobilidium gyrans。(4) The trend of temporal and special dynamic changes in Sarcomastigophorarichness within two seasons was1~#sample in summer (1880ind./mL)> autumn (1640ind./mL),2~#sample in summer (1060ind./mL)> autumn (560ind./mL),3~#sample insummer (1720ind./mL)> autumn (490ind./mL),4~#sample in summer (3610ind./mL)> autumn (1540ind./mL),5~#sample in autumn (900ind./mL)> summer (790ind./mL). The trends of Sarcomastigophora richness in summer was4~#>1~#>3~#>2~#>5~#and1~#>4~#>5~#>2~#>3~#in autumn. The overall trend was decreasing from sample1~#to5~#and summer> autumn.The trends of Ciliophora richness in summer was:1~#sample in summer (2880ind./mL)> autumn (440ind./mL),2~#sample in summer (1440ind./mL)> autumn (279ind./mL),3~#sample in summer (600ind./mL)> autumn (300ind./mL),4~#sample insummer (340ind./mL)> autumn (250ind./mL),5~#sample in summer (460ind./mL)>autumn (410ind./mL). The trends of Ciliophora richness in summer was1~#>2~#>3~#>5~#>4~#and1~#>5~#>3~#>2~#>4~#in autumn. The overall trend was decreased in the beginning and then increased later from sample1~#to5~#and summer> autumn.(5) Richness index: the richness index of Sarcomastigophora was changingfrom3.68~8.99. The trends of changes from the sampling sites was5~#>1~#>2~#>3~#>4~#in summer and,5~#>3~#>1~#>2~#>4~#in autumn; overall change of richness index wasdecreased from1~#to5~#. The temporal and special dynamic changes of Ciliophora was1~#sample in summer (5.65)> autumn (5.59),2~#sample in autumn (4.62)> summer(4.40),3~#sample in summer (6.13)> autumn (5.01),4~#sample in summer (5.67)>autumn (4.35),5~#sample in summer (5.87)> autumn (5.15). Richness index ofCiliophora was changing from4.35~6.13within the5sample sites, and the trendsbetween sample was3~#>5~#>4~#>1~#>2~#in summer,1~#>5~#>3~#>2~#>4~#in the autumn.(6) Diversity index: the diversity index of Sarcomastigophora was changing from3.68~8.99in two seasons. The trends of changes from1~#to5~#was5~#>2~#>1~#>3~#>4~#insummer and5~#>3~#>2~#>1~#>4~#in autumn, overall changes of index was higher insummer than in the autumn. The range of dynamic changes in diversity index of theCiliophora was1.61~3.53within two seasons, the trends of changes from sample1~#to5~#was4~#>5~#>3~#>1~#>2~#in summer and3~#>1~#>2~#>4~#>5~#in autumn, summer was higherthan autumn as a whole.(7) Evenness index: The range of temporal and special dynamic changes withevenness index of Sarcomastigophora was0.47~0.93in two seasons, the trends ofevenness index change was5~#>2~#>1~#>3~#>4~#in summer and3~#>2~#>5~#>1~#>4~#inautumn with5sample sites and the evenness index was gradually increasing from1~#to5~#. The range of temporal and special dynamic changes with evenness index ofCiliophora was0.47~0.93in two seasons, the trends of changes during summer timewas4~#>5~#>3~#>1~#>2~#and3~#>1~#>2~#>4~#>5~#in the autumn, the index was higher insummer than in autumn as a whole.(8) Saprobic index: the range of saprobic index in Sarcomastigophora waschanging between0.96and1.27and the trends of dynamic change in saprobic indexwas1~#>3~#>2~#>4~#>5~#during summer time and4~#>3~#>5~#>2~#>1~#for autumn. Overall,the trend of change was decreased in summer time and incresed during the autumn.The range of dynamic changes with saprobic index of Ciliophora was1.60~2.06during two seasons, he trends of dynamic change in saprobic index was 2~#>4~#>1~#>3~#>5~#from sumple1~#~5~#in summer and4~#>2~#>5~#>3~#>1~#; as a wholeincreasing in the autumn and decreasing during the summer time gradually.(9) Tempraral and spacial changes in functional group: the BS functional groupof Sarcomastigophora was changing between41%~57.0%in two seasons. The trendsof BS functional group of Sarcomastigophora in temporal and special change was4~#>5~#>3~#>2~#>1~#and it shows increasing step by step. During the autumn time thechange was3~#>5~#>4~#>1~#>2~#，and the trends was higher in the beginning and lowerin later.(10) Major environmental parameters: pH, water temperature, electricalconductivity, Total Dissolved Solids and salinity were analyzed.(11) Correlation analysis were conducted between community structureparameters of Protozoa and environmental factors, the result shows that communitystructure parameters of Protozoa and environmental factors were significantlycorrelated (P<0.05or P<0.01) in Lhalu wetland.(12) Evaluation for aquatic environmental quality of Lhalu wetland wasconducted using community characteristics of Protozoa and environmental factors.The result showed that the wetland was in good condition during summer and autumn,but there were some impact from human activities showing from samping sites1~#and4~#.