Abstract:
Benthic animals are an important component of wetland ecosystems, playing a crucial role in energy conversion and pollutant removal. A study on the subtropical hilly area of Changsha, Hunan Province was conducted to determine the community characteristics of the zoobenthos in floating plant, emergent plant, and no-plant surface flow constructed wetlands over four years of continuous field experiments. The zoobenthos community structure in CWs located in subtropical hilly areas were found to be simple, with a total of only 36 species collected during the experiment period.
Limnodrilus hoffmeisteri was identified as the most dominant species, with a dominance value up to 0.5. The average abundance and biomass of zoobenthos were 909 ind/m
2 and 96 g/m
2, respectively. However, there was a declining trend in the number, abundance, and biomass of zoobenthos species from year to year. The characteristics of zoobenthos community were found to be influenced by both water quality and climate conditions. The abundance and number of species of the zoobenthos were positively correlated with NH
3-N and TN concentrations, while the species richness and evenness index of zoobenthos had a positive correlation with water temperature but a negative correlation with pH. Different classes of zoobenthos were affected by different environmental factors;
Oligochaeta had a significant positive correlation with TN and NH
3-N, while
Gastropoda and
Insecta had a significant positive correlation with TP and COD. The results showed that zoobenthos are vital indicators of water quality change, and that they also play an important ecological role in augmenting the absorption and transformation of pollutants in CWs. Furthermore, they are a significant way to improve economic benefits in CWs and are therefore worth further study.