Abstract: Soil carbon storage of wetland ecosystems plays an important role in global carbon budget. In terms of coverage of wetland, three types of sites, including high, medium and low coverage, were sampled in Wowachi herbal marsh wetlands of National Nature Reserve of Dunhuang Yangguan. Soil samples at 0-20, 20-40, 40-60 cm layers were taken from 53 plots to explore the distribution of soil organic carbon (SOC) and its influence factors. The results showed that the SOC concentrations at 0-60 cm depths were 4.94-25.89, 4.77-13.89, and 3.56-11.42 g·kg^-1 at high, medium and low coverage sites, respectively. The differences in SOC at 0-20 cm and 40-60 cm depths were significant between high, medium and low coverage (P<0.05). The spatial variation of SOC was the largest in wetland with high coverage, and it was the smallest in wetland with medium coverage, while it was intermediate in wetland with low coverage. The SOC was positively correlated with soil moisture, total nitrogen, total phosphorus and N:P ratio (P<0.01), but it was negatively correlated with soil salinity and soil bulk density (P<0.01). Soil moisture was the key factor affecting SOC accumulation. Our results can provide scientific basis for wetland protection, management and ecological restoration in this arid region.

Key words: pollination, nectar robbing behavior, Xylocopa, foraging behavior