Species richness and influencing factors of aquatic plant in the Kaidu River Basin, Xinjiang, China

Abstract

River is a continuous, flowing, unique, and complete ecosystem. Studies on the aquatic macrophyte richness and its influencing factors were important for river ecology study. In this study, species richness, main aquatic plant community types and their quantitative characteristics, and the influencing factors of aquatic macrophyte in the Kaidu River Basin, Xinjiang, were examined by field investigation. We followed the water-energy hypothesis and habitat heterogeneity hypothesis to explain the geographical pattern of species diversity in the basin. The results showed that there were 71 species of aquatic plants belonging to 24 families and 39 genera in the Kaidu River Basin. The aquatic macrophyte communities could be divided into 10 main community types by cluster analysis, among which Phragmites australis association had the highest species richness, and Typha angustifolia association and Ceratophyllum demersum association had the lowest species richness. Shannon index of the aquatic macrophyte community of Kaidu River Basin was significantly negatively correlated with water pH. Simpson index was significantly negatively correlated with pH and longitude, and significantly positively correlated with altitude. The aquatic plant community types in the basin were mainly affected by altitude, water depth, and water temperature. The species diversity changed little in altitude and longtitude. The water-energy dynamic hypothesis and habitat heterogeneity hypothesis together explained 31.4% of the richness patterns of macrophytes, indicating low exploratory power.