Community Of Phytoplankton In Anbang River Wetland Nature Reserve

The wetland is one of most important and multi-functional ecosystems on the earth, known as "kidney of the earth". The ecological study of phytoplankton was conducted on ten typical sampling stations selected in Anbang River wetland Nature Reserve in summer, autumn, 2005, and in spring, 2006. Phytoplankton communities and biodiversity were examined with multivariate statistic analysis. The Pearson analysis and gray association analysis were used to detect the correlation between hytoplankton and environmental factors. The purpose of this paper was to provide a guideline of management and a foundation for the future study in Anbang River wetland Nature Reserve.Total of 8 phyla 106 species were identified, among which, the majority were Clorphyta (48) and Cyanophta (25), followed by Bacillaroiphyta (21), the other was 12, and Clorphyta was the dominant group in total phytoplankton. The total mean abundance and biomass were 183.32×10~4ind./L and 2.92mg/L. There was big change in species number, abundance and biomass between season and sampling stations by ANOVA. The temporal and spatial distribution of abundance and biomass were summer > autumn > spring, upstream region > region, and edge area > core area.There were different ranges in different diversity index, Shanno-Veaner's index from 3.02 to 3.77, Margalefs index from 0.96 to 1.44, Pielou's index from 0.61 to 0.88, respectively. Seasonal variation of Shanno-Veaner's index and Pielou's index were spring > autumn > summer, and Margelef's index was summer > autumn > spring. Horizontal distribution of diversity were upstream region > region, and core area > edge area. Change of diversity was correlation with distribution of environmental factors. The hierarchical cluster analysis revealed that the phytoplankton community structure in Anbang River wetland Nature Reserve were classed three groups, the comparability was high within groups and the great change between groups. The results of nor-matric multidimentional scaling (MDS) was same of the hierarchical cluster analysis, and showed the change was for the change of hydrographic factor and vegetation.Based on Pearson analysis, the results showed that the phytoplankton varied with the changes of environmental factors. Water temperature was positively related to the abundance and biomass (p<0.01, p<0.05). Correlation between dissolved inorganic nitrogen (DIN) and abundance, biomass was positively significant at 0.01 level and in spring, but in summer and autumn was negatively (p<0.01). The phytoplankton abundance and biomass were positively correlated to inorganic phosphate (IP) in three seasons, and their correlation were significant at 0.01 or 0.05 level, the results demonstrated that inorganic phosphate (IP) was the limit )factor of the growth of phytoplankton in all year. The correlation of abundance, biomass and dissolved oxygen (DO) were positively significant at 0.01 level in spring, abundance and dissolved oxygen (DO) at 0.05 level in autumn, and the other was p>0.05. The relationship between phytoplankton abundance, biomass and diaphaneity was positively, but p>0.05. There existed a significant correlation between PH and phytoplankton in spring and summer (p<0.01), but in autumn was not significant correlation (p>0.05). The result of grey relational analysis suggested that the factor which seriously influenced phytoplankton was nutrient factor. Thus, it is important to control the exogenous nutrient to maintain ecosystem healthiness of Anbang River wetland Nature Reserve.