Assessment In Depth on the Anti-seasonal Water Fluctuations and Vegetation Dynamic Trends in a Plateau Lake, Southern China

Abstract

Human activities, such as dam construction for flow regulation, modify the natural hydrological regimes of lakes and rivers. The altered flow regimes substantially influence plant growth in the water level fluctuation zone, impacting both vegetation patterns and success. The relationships among above-ground vegetation, soil seed bank and soil microorganisms remain unexamined. This study was performed in Lashi Lake, a plateau lake in southern China characterized by anti-seasonal water level fluctuations, and Jizi Reservoir, a reference site exhibiting natural seasonal water level variations. The primary aim was to assess the distribution pattern of plant, soil seed bank and their corresponding soil microorganism over the three flood gradients, and the relationships among them were analysed simultaneously. The findings indicated that both plant community variety and seed bank diminished as the area of soil flooding increased. The soil seed bank was a strong indication of community diversity, particularly throughout late spring and late summer. Additionally, significant correlations between the alpha diversity of soil microorganisms and the concentrations of soil carbon, nitrogen and moisture were found across the flooding gradients. The organization and diversity of soil microbial communities were significantly correlated with the alpha diversity of the plant community and the soil seed bank. The findings demonstrate that both seed banks and soil bacteria play a dynamic role in the restoration of vegetation in areas experiencing anti-seasonal water fluctuations.