Distribution of Aquatic Macrophytes in Relationship to Physicochemical Parameters from 2016 to 2021 in Hongze Lake, China

This study focused on the relationships between aquatic macrophyte species composition, species biomass, distribution, and the physicochemical parameters in Hongze Lake from 2016 to 2021. A total of 26 aquatic macrophytes from 15 families and 20 genera were identified, including 12 species of submerged plants, 5 species of floating-leaved plants, 4 species of free-floating plants, and 5 species of emergent plants. The dominant species were Myriophyllum spicatum, Potamogeton crispus, Stuckenia pectinata, Potamogeton crispus, Potamogeton wrightii, Ceratophyllum demersum, Trapa bispinosa, Nymphoides peltata and Nelumbo nucifera. Myriophyllum spicatum was the most widely distributed species, while Potamogeton maackianus had the highest biomass. Both annual and seasonal variations affected species' biomass and structure. Submerged plants were primarily distributed in the northern part of the lake. Floating-leaved and emergent plants were mainly distributed in the central of the lake. Using Pearson analysis and redundancy analysis (RDA), the relationships between 9 dominant species and 11 physico-chemical parameters were investigated. The results indicated that temperature, pH, water transparency, permanganate index (CODMn), five-day oxygen demand (BOD5), total nitrogen, and total phosphorus had a strong influence on aquatic macrophyte biomass. The results of this study can provide a reference for water ecological health and aquatic macrophyte restoration.