Abstract: Wetland is an important carbon pool. Exploring the carbon storage of wetlands is significant to global carbon cycle and wetland conservation. Here, we investigated plant community diversity and soil organic carbon storage in Baishanzu Huangpi wetland, a subtropical subalpine marsh. The results showed that: (1) A total of 54 plant species (belonging to 26 families, 44 genera) were recorded. Most species were from the Cyperaceae family (13 species), followed by Poaceae (5 species). The remaining species were scattered in other families. (2) There was no significant difference in species richness and Shannon index among four typical communities. The Simpson index and Pielou index of the Rhynchospora faberi community were significantly lower than other three communities. The Rhynchospora faberi community had the highest carbon storage (1225.36 g·m^-2). (3) There were no significant differences in biomass and aboveground/underground biomass ratio among six dominant species, whereas carbon storage, and aboveground/underground carbon storage ratio showed significant difference. The carbon content of roots, stems and leaves of the six dominant species were higher than 40%. (4) Soil organic carbon content and density of Huangpi wetland were relatively high. The total ecosystem carbon storage was 0.018 Tg. Compared with other wetlands, Huangpi wetland had a higher carbon density and stock. Therefore, Huangpi wetland provides a good carbon sink function and has high conservation value.

Key words: Shannon index, aboveground/underground C content, aboveground/underground biomass, vegetation carbon storage, ecosystem carbon storage