Fish Community Structure and Ecological Health Assessment of the Shuaishui River Basin, China

The Shuaishui River originates from the southern mountainous area of Anhui Province and is an important water source for local residents. The ecological environment of this basin has been seriously damaged because of the effects of human disturbance. In August 2016, a field study of five units of the Shuaishui River Basin was conducted to understand the fish community structure and assess the ecological health status. A total of 43 fish species were collected from the entire river basin, and they belonged to 4 Orders, 10 Families, and 31 Genera. The maximum number of species belonged to the family Cyprinidae, and the main trophic guild was omnivorous fish. Among the five units, species number was the highest in unit 2 (27 species) and the lowest in unit 3 (12 species). The dominant species in the five units were mainly typical mountain-stream fish, such as Zacco platypus, Acrossocheilus fasciatus, and Vanmanenia stenosoma. In some areas, Varicorhinus barbatulus or Rhinogobius cliffordpopei also showed great dominance because of the impacts of the local habitat conditions. Redundancy analysis showed that altitude, water velocity, stream order, and water surface width were the main factors that influenced the distribution and species composition of the fish. Eigenvalues of the first two axes were 0.183 and 0.082 and explained 40.9% and 18.3% of the species-environment relationship variables, respectively. The ecological health of the five units and the entire basin was assessed based on the arithmetic mean of three indicators, namely, number of classification units, Shannon-Wiener index, and Berger-Parker dominance index. The results indicated that the ecological health status was relatively poor in unit 3, general in units 1 and 5, and good in units of 2 and 4. The status of the entire basin was general. To the best of our knowledge, this is the first comprehensive assessment of the ecological health of the Shuaishui River Basin, and it has great significance for the ecological management and protection of this basin.