Macrobenthos Community Structure And Biological Evaluational Research Of Water Quality In Hailang River

The wetland is one of most important and multi-functional ecosystems on the earth, known as "kidney of the earth". The ecological study of macrozoobenthos was conducted on ten typical sampling sections selected in Hailang River, in spring, summer, autumn and winter from2009to2010. Macrozoobenthos communities and biodiversity were examined with multivariate statistic analysis. The Canonical Correspondence Analysis was used to detect the correlation between macrozoobenthos and environmental factors. The purpose of this paper was to provide a guideline of management and a foundation for the future study in Hailang River wetland.Total of55species were identified, among which, the majority are aquatic insects (38), accounting for69.1%; followed by annelid,11species, accounting for20.0%; five kinds of mollusks, accounting for9.1%; one crustacean species, accounting for1.8%. The total mean abundance was536.4ind./m2. There was big change in species number and abundance between season and sampling stations. The temporal and spatial distribution of abundance was summer>winter>spring>autumn, the spatial variation for the upstream and the middle reaches is higher than the downstream, such differences associated with environmental factors in the distribution.There were different ranges in different diversity index, Shannon-Wiener index throughout the year between0.60and5.00, the highest in summer, to3.89, the lowest in autumn, to1.13;Margalef index throughout the year between0.41and2.58, the maximum value appears in the summer, to1.71, the minimum value appears in the autumn, to0.91, BI index throughout the year between3.89and9.59, the maximum value appears in the autumn, to8.76, the lowest in the summer, to6.29; Goodnight-Whitely amendment index throughout the year between0.9%and99.6%, the maximum value appears in the spring, the lowest value appears in the summer. Shannon-Wiener index trends are summer>winter>spring>autumn; Margalef index is the summer>spring>winter>autumn; BI index is autumn>spring> winter> summer; Goodnight-Whitely index is spring>autumn>winter>summer.The TWINSPAN cluster analysis revealed that the macrozoobenthos community structure in Hailang River was classified into three or four groups, the comparability is high within groups and the great change between groups. The results showed the change was for the change of hydrographic factor and vegetation. The impact of the various environmental factors on macrozoobenthos communities differs for the change of seasons. The result of canonical correspondence analysis suggested that dissolved oxygen, water temperature and nutrient have the greatest impact on the distribution of macrozoobenthos in Hailang River.According to the pollution index, water around section1#,4#,5#are seriously contaminated, water quality in other sections are polluted at different levels.