Plant Community Characteristics During Natural Succession in Restored Wetlands of the Lower Tumen River

Wetlands are ecosystems with critical functions. However, the accelerated progression of global urbanization and human activities, including agricultural encroachment, has resulted in a notable decline in wetland areas and the degradation of wetland quality worldwide. Consequently, wetland restoration has become a central focus of wetland research. Plant community characteristics are among the simplest and most frequently used indicators for evaluating wetland restoration progress and are a crucial factor in maintaining the health and stability of wetland ecosystems. Therefore, this study aimed to investigate the plant community characteristics of restored wetlands with different durations of abandonment in the lower Tumen River Basin, which is expected to provide guidance for promoting the restoration of abandoned farmlands in this region. We hypothesize that species diversity decreases with increasing abandonment age, plant community composition converges toward that of natural wetlands over time, and beta diversity declines due to increasing biotic homogenization during succession. We established a chronosequence of abandoned wetlands in the lower Tumen River Basin, with sites abandoned for approximately 5, 15, and 30 years. And we use natural wetlands and paddy fields as references. With natural succession, the dominant plant species in the restored wetlands transitioned from annuals/biennials to perennials. The aboveground biomass initially increased and subsequently decreased. A gradual decline in species diversity was observed along with a further reduction in beta diversity, and the species turnover component consistently exceeded the richness difference component. The pronounced biotic homogenization among communities indicates that achieving a stable state comparable to that of natural wetlands may require considerably more time or may not be attainable solely through natural succession.