Different Stages of Aquatic Vegetation Succession Driven by Environmental Disturbance in the Last 38 Years

In recent years, investigating the trend of aquatic plant diversity in response to different disturbance events has received increasing interest. However, there is limited knowledge of the different stages of aquatic vegetation succession over a long period in eutrophic lakes. In this study, we analyzed aquatic plant species richness and its relation to the physical and chemical characteristics of water in Chenghai Lake for the period of 1980-2018. This study shows that the richness and distribution of aquatic vegetation in Chenghai Lake are related to chlorophyll-a concentration, dissolved nutrients, base cations, and micronutrients. The results show that the long-term succession of aquatic plants in this lake classified in different stages: (I) A peak in species richness occurred at an intermediate stage that lasted from 1980 to 1992, and this was caused by more aquatic species being able to coexist since the competition for resources was lower; (II) after 26 years of secondary succession (1992-2018), the diversity and distribution area of aquatic plants gradually declined because pioneer species or human activities may have altered habitat conditions to render habitats less beneficial to pioneer species and more suitable for new aquatic plant species. Thus, species diversity and growth performance of aquatic plants in their communities may be useful indicators of Chenghai Lake's trophic status, especially during the transition period from a mesotrophic lake to a eutrophic one.