Spatio-temporal distribution characteristics and driving factors of phytoplankton community in Duchang Migratory Bird Nature Reserve of Lake Poyang, China: a 9-year study

Eutrophication of water bodies used as migratory bird habitats will lead to a sharp increase in the abundance of phytoplankton, mainly cyanobacteria. These changes will affect the species distribution of migratory birds, thus damaging the ecological balance of affected habitats. We used 9-year field quarterly data of phytoplankton and environmental factors in the Duchang Reserve (2011 to 2016 and 2019 to 2021) as the basis to analyze the temporal and spatial distribution characteristics of phytoplankton, and explore the phytoplankton community succession and its driving factors through redundancy analysis. The results show that (1) during our sampling, 7 phyla and 93 genera of phytoplankton were identified; (2) the nutrient content of the water in Duchang Nature Reserve decreased, but the phytoplankton increased; (3) the factors influencing phytoplankton shifted from initially nutrient controlled to hydrological control; and (4) the driving factors of phytoplankton are seasonal. Nutrients are the main driving factor of phytoplankton in the dry season (January), while hydrological factors have a greater impact on phytoplankton in the wet season (July) and dry season (October).