Dataset of Herbivorous Wintering Waterbirds Excreta and Carex Decomposition in Poyang Lake

Based on litterbag decomposition experiments of Carex and excreta addition trials of herbivorous wintering waterbirds (Anseriformes) conducted on Poyang Lake's lakeshore beaches in 2017, this study systematically investigates wetland organic matter decomposition and carbon-nitrogen-phosphorus cycling mechanisms. Results demonstrate that bird excreta addition significantly accelerated Carex litter decomposition, with mixed treatments exhibiting substantially lower residual rates for dry matter (66.80% vs. 71.96%), lignin (61.03% vs. 69.97%), and cellulose (44.54% vs. 62.53%) after 150 days compared to Carex-alone treatments, alongside significantly higher nutrient release rates indicated by relative return indices for carbon (42.73% vs. 34.91%), nitrogen (53.95% vs. 17.96%), and phosphorus (14.65% vs. 5.70%). Although bird excreta decomposed slowly, it displayed high nitrogen and phosphorus release characteristics. These findings indicate that wintering waterbirds introduce allochthonous nutrients and microbial communities through excretion, likely enhancing decomposition of structural components (cellulose, lignin) and net release of C-N-P elements by altering substrate composition, increasing nutrient availability, and stimulating microbial degradation activity. Consequently, this process profoundly influences wetland biogeochemical cycling and carbon pool dynamics, providing critical scientific foundations for refining global carbon models and guiding wetland ecosystem management.