Assessment of planktonic community diversity and stability in lakes and reservoirs based on eDNA metabarcoding——A case study of Minghu National Wetland Park, China

To evaluate the potential differences in plankton diversity and stability within freshwater lake and reservoir ecosystems, this study employed eDNA metabarcoding to analyze the diversity, assembly mechanisms, stability, and environmental drivers of plankton communities in natural water (Y region) and artificial lake water (M region) at Liupanshui Minghu National Wetland Park, Guizhou Province, China. The study revealed notable regional variations in plankton diversity and assembly mechanisms. Specifically, Shannon, Simpson, and Pielou's evenness indices were higher in the M region, suggesting a more complex species composition compared to the Y region. Analysis of community assembly mechanisms indicated that both regions were influenced by a combination of stochastic and deterministic processes, with stochastic processes serving as the dominant driver. Through LEfSe analysis, Random Forest predictions, and molecular ecological network evaluations, certain OTUs identified as "dual-characteristic" species were consistently highlighted. These species may play a critical role in shaping community composition and contributing to stability. Environmental drivers further clarified these differences. Redundancy analysis (RDA) demonstrated that TDS was the primary factor driving regional differences in key zooplankton species, while EC and DO were significant factors influencing the distribution of key phytoplankton species. Stability assessments, which combined molecular ecological network analysis and the coefficient of variation in species population density, revealed higher stability in the Y region. This indicates that the natural water system (Y region) has a greater resistance to disturbances compared to the artificial system in the M region. The findings provide fundamental support for assessing the health of aquatic ecosystems, as well as for the effective monitoring and biodiversity conservation of lake and reservoir ecosystems.