Effects of yak grazing on CO2 fluxes in peat bogs in the Northwest Yunnan Plateau

To assess the impacts of yak excreta and trampling on carbon dioxide (CO2) fluxes inatypical peat bog in the Bitahai wetland in the Northwest Yunnan Plateau, CO2 fluxes weremeasured in yak dung, yak trampled areas, yak dung intrampled areas (as an indicator of the interaction of yak dung and yak trampling), and control areas during the summer grazing season in 2015. The results showed that yak grazing significantly affected the emissions of CO2 of peat bogs in the Bitahai wetland. The fluxes of CO2 from different grazing treatments were characterized by yak dung>yak dung and trampled>control>yak trampled(P<0.05). During the experimental period, the average amount of CO2 fluxes from yak dung, yak dung and trampled, control, and yak trampled areaswere14.38, 9.48, 4.71, and 2.60 μmol·m-2·s-1, respectively. Fluxes of CO2 in the control area had a significant positive correlation with the temperature of the upper 10 cm soil (P<0.05). In contrast, fluxes of CO2 in yak dung, yak trampled, and yak dung and trampled areas had no correlation with the upper 10 cm soil temperature. These results indicated that yak dung improvedthe fluxes of CO2 in peat bogs, but yak trampling had the opposite effect. Yak grazing decreasedthe effect of soil temperature on the fluxes of CO2 in peat bogs.