Modeling macrozooplankton and water quality relationships after wetland construction in the Wenyuhe River Basin, China

The biodiversity of macrozooplankton and physicochemical indices at eight sites in the Wenyuhe River Basin were analyzed from April 2010 to March 2011 to assess the water quality following construction of a wetland (CW). The association between biodiversity and physicochemical parameters was analyzed using a self-organizing map (SOM). The water quality in the upstream portion of the CW showed no overall improvement during this period based on biodiversity (H′) and physicochemical assessment (Pb/n). Both assessments indicated that the water quality in upstream of CW was partially improved and showed an evident time dependent relationship after CW. Although a sample site, which received water from two streams, showed higher biodiversity in an integrative manner, the physicochemical assessments were more heavily influenced by treated water from the Qinghe Sewage Treatment Plant, rather than upstream at the other river basin. This was a noteworthy demonstration that physicochemical and biological assessments were not in accord and addressed the separate functioning of river ecosystems under field conditions. Physicochemical assessment may represent water quality more conservatively with respect to drinking water maintenance than biodiversity assessment. Nitrogen pollution was the main cause for the decrease in physicochemical conditions. Overall, the results indicated that the association between biodiversity and physicochemical assessments determined from the SOM could reveal aquatic ecosystem quality in a comprehensive manner and therefore be a useful tool for defining water quality and ecological integrity in aquatic ecosystem management, especially for complex water environments.