Abstract: Aboveground biomass is a key metric for assessing ecosystem structure and function. Worldwide, sedge wetlands are distributed across temperate marsh and montane regions and have critical ecological functions including carbon storage, biodiversity maintenance, and climate regulation. However, little is known about aboveground biomass patterns at landscape scales in sedge wetlands. In this study, we combined field data from 125 sedge wetland sites with remote sensing information on solar radiation and climate to evaluate the impact of abiotic (e.g. solar radiation, climate, soil properties, and water regime) and biotic (e.g. plant species richness and community type) factors on aboveground biomass. Our results reveal significant heterogeneity in the aboveground biomass of sedge wetlands across different climatic zones in China. Both abiotic and biotic factors exerted influences on aboveground biomass variation in sedge wetlands, although biotic factors dominated patterns of aboveground biomass. The aboveground biomass was promoted by plant species richness, while the relationship between aboveground biomass and species richness was modulated by community type. Furthermore, mean annual precipitation was identified as the most effective abiotic indicator of aboveground biomass, exhibiting a positive correlation with aboveground biomass. Soil properties directly affected aboveground biomass, and indirectly through species richness and community type. Our study demonstrates the importance of abiotic and biotic drivers on the productivity of sedge wetlands in China and helps predict the response of wetland function to future environmental changes.

Key words: Aboveground biomass, biodiversity-ecosystem functioning, species richness,  climate zone, environmental change, sedge wetlands