Zooplankton community structure and its influencing factors in the Henan section of the Yellow River

We conducted a sampling survey of zooplankton at typical sections (mainstream, tributaries, and reservoirs) of Henan section of the Yellow River in July 2021, and analyzed the zooplankton community structure and key influencing factors. The results showed that a total of 32 genera and 47 species of zooplankton were recorded, with the density ranging from 0.4 ind·L^-1 to 612.8 ind·L^-1. The dominant species were Brachionus calyciflorus, Keratella cochlearis, and Asplanchna priodonta. The mainstream exhibited higher community diversity but lower abundance, while the tributaries had lower diversity but higher abundance, indicating high spatial heterogeneity in the zooplankton community structure. Resource use efficiency of zooplankton in the tributaries was significantly higher than that in the mainstream and reservoirs, reflecting the richness and high quality of food resources for zooplankton in the tributaries. The main environmental factors influencing the zooplankton community structure were electrical conductivity, ammonium nitrogen, and the permanganate index.