Investigation on the status quo of aquatic plant biodiversity in the riverways and littoral zones of the Lake Taihu rim

Abstract

The Lake Taihu rim has a robust economy and a dense population. In recent years, this area is facing severe environmental problems such as eutrophication, habitat degradation and invasion of introduced aquatic species. Aimed to clarify the status quo of aquatic plant bio-diversity in riverway and littoral zone of the Lake Taihu rim, surveys on native and introduced aquatic plants were performed in this area in 2018. The results indicate that: (1) In total, 38 aquatic plants species in 22 families and 29 genera were recorded in 65 community quadrats in the Lake Taihu rim in 2018; (2) An invasive submerged plant Cabomba caroliniana has the highest relative importance value (RIV) among 31 riverway quadrats, followed by an invasive free-floating plant Eichhornia crassipes, and the latter one has the highest RIV among 34 littoral zone quadrats; (3) The aquatic plant biodiversity indices decreased with the increasing coverage of C. caroliniana and E. crassipes in riverway and littoral zone quadrats, respectively, indicating that the invasive plants had an impact on the biodiversity of aquatic plants. The expanding distribution of the free-floating plant E. crassipes, and the possible invasion of the submerged plant C. caroliniana alongside river channels should be monitored in the Lake Taihu. Facing the problems of reducing coverage of aquatic plants and the invasion of introduced plants, it is recommended to conduct a full investigation on the distribution area and bio-diversity of aquatic plants, enhance supervisory control on the spread of introduced species, and establish natural reserves on aquatic plants in the Taihu Basin.