Our research investigates the transformation of aquatic plant diversity in the Lake Taihu drainage basin (LTDB), located in one of China's most developed regions. We focused on the impact of three major invasive species: water hyacinth (Eichhornia crassipes), Carolina fanwort (Cabomba caroliniana), and alligator weed (Alternanthera philoxeroides). These three species have contributed to a shift from a native plant-dominated ecosystem to one increasingly dominated by invasive species, disrupting the biodiversity of freshwater ecosystems in the region.
E. crassipes stands out due to its unique poly-herringbone root branching system, which significantly enhances its ability to absorb nutrient elements. This adaptation allows the species to thrive in nutrient-rich habitats, promoting its rapid growth and spread. With climate warming, the overwintering success of E. crassipes may spread further, facilitating its persistence and growth which turn this annual plant to perennial plant. This combination of rapid growth, efficient nutrient uptake, and overwintering resilience enhances its invasive potential. We also discovered that the leaf metabolomic traits of A. philoxeroides, particularly its zeatin and purine metabolism, are key indicators of its invasion success, especially in urban and periurban wetlands. These metabolomic traits appear to play a more significant role in its invasiveness than traditional leaf functional traits. The success of A. philoxeroides in urban wetlands highlights the ability of certain invasive species to exploit disturbed and nutrient-rich environments, allowing them to dominate and outcompete native plants. Similarly, C. caroliniana has become a major invasive threat due to its ability to form dense, mono-species communities, particularly under low underwater photosynthetically active radiation (PAR) conditions. This species exhibits high resistance to native herbivores, a critical factor that supports its spread. Additionally, C. caroliniana has favorable growth traits under fluctuating environmental conditions, including its ability to proliferate through stem fragmentation. This rapid mode of propagation complicates its management, as it indicates that C. caroliniana has not yet reached its distributional limit in the LTDB.
Our findings underscore the urgency of developing effective management strategies to mitigate the decline in aquatic biodiversity. It is essential to implement targeted removal and restoration initiatives to control the spread of these three species. Moving forward, efforts should focus on preserving the ecological integrity of freshwater ecosystems in the LTDB by addressing the spread of these invasive species. Effective management will not only help maintain biodiversity but also restore the vital functions of aquatic ecosystems in the region.