Abstract
BACKGROUND: The effects of grazing on soil methane (CH(4)) uptake in steppe ecosystems are important for understanding carbon sequestration and cycling because the role of grassland soil for CH(4) uptake can have major impacts at the global level. Here, a meta-analysis of 27 individual studies was carried out to assess the response patterns of soil CH(4) uptake to grazing in steppe ecosystems of China. The weighted log response ratio was used to assess the effect size. RESULTS: We found that heavy grazing significantly depressed soil CH(4) uptake by 36.47%, but light and moderate grazing had no significant effects in grassland ecosystem. The response of grassland soil CH(4) uptake to grazing also was found to depend upon grazing intensity, grazing duration and climatic types. The increase in soil temperature and reduced aboveground biomass and soil moisture induced by heavy grazing may be the major regulators of the soil CH(4) uptake. CONCLUSIONS: These findings imply that grazing effects on soil CH(4) uptake are highly context-specific and that grazing in different grasslands might be managed differently to help mitigate greenhouse gas emissions.