Yahui Mao ¹ Yangong Du ^2* Kelong Chen ¹

• ¹ Qinghai Normal University, Xining, Qinghai Province, China
• ² Northwest Institute of Plateau Biology, Chinese Academy of Sciences (CAS), Xining, China

Grazing activities were intensive in alpine grasslands, and may alter the soil respiration rates across the Tibetan Plateau. However, grazed alpine grassland soil respiration rates and their underlying driving mechanisms remain unclear across the Tibetan Plateau. In this study, we synthesized 38 groups data to clarify the response of CO2 emission rates to different grazing intensities. The effect size was 0.039 ± 0.051 of grazed activity on the ecosystem respiration rates, indicating that grazing increased respiration rates by 3.99%. Furthermore, effect sizes were -0.146 ± 0.209 and 0.076 ± 0.046 in alpine steppes and alpine meadows, indicating 13.58% reduction and 7.90% increasement. The effect sizes were 0.051 ± 0.112, 0.029 ± 0.075 and 0.055 ± 0.089 in light, moderate and high grazing intensity. Moderate grazing benefited to mitigate grassland CO2 emission rates compared with light and high grazing. Both air temperature and soil organic carbon significantly increased grasslands ecosystem respiration rate explaining 38.47% and 22.57% of variances heterogeneity. In addition, both future global warming and increasing soil organic carbon would increase alpine grasslands CO2 emission rates on the Tibetan Plateau.