Effects of environmental and biological characteristics on leaf decomposition under wetland restoration conditions

The implementation of ecological restoration projects, such as wetland rehabilitation, is essential for achieving sustainable development. However, current research on monitoring recovery status primarily focuses on evaluating water quality and aquatic community structure, with limited understanding of macroinvertebrate and microbial networks, as well as the functions of restored ecosystems. To address this gap, we compared the leaf decomposition rates of reed ( Phragmites australis ) and sedge ( Carex appendiculata ) in short-term (1, 2, and 3 years) and long-term (17 years) restoration wetlands, using natural wetlands as controls to assess ecosystem function. Our results indicate that the leaf decomposition rate in restored wetlands is significantly lower than in natural wetlands. No significant difference in decomposition rates was detected between the two types of leaves ( P >0.05). All evaluation categories, including biological network structure, influenced leaf decomposition in different wetlands, with distinct effects observed on reed and sedge leaves. Compared to sedges, the decomposition of reed leaves exhibited a stronger correlation with macroinvertebrates while showing a weaker association with microorganisms and co-occurring network topological parameters. Overall, the execution of wetland restoration projects positively influences the recovery of biodiversity co-occurrence networks and ecosystem functions. These findings provide valuable insights for environmental and sustainability assessments. • Wetland restoration promotes the restoration of ecosystem functions, mainly in the rate of leaf decomposition. • Biological network complexity showed a trend of decreasing and then increasing with restoration time. • Biological network complexity influences leaf decomposition.