Response of Carbon Balance to Grazing Intensity in Alpine Grassland Ecosystem of the Qinghai-Tibet Plateau
The Tibetan Plateau has the world's most extensive alpine grassland and a long history of grazing that dates back thousands of years.The unique alpine environment conditions make it more sensi-tive to external disturbances.Although many studies have been conducted on the carbon cycling of alpine grassland ecosystems on the Qinghai-Tibet Plateau,how grazing,especially grazing intensity,affects the carbon balance of alpine grassland still needs further studies and clarification.This paper reviews the re-sponse of carbon balance of alpine grassland ecosystem to different grazing intensities on the Qinghai-Tibet Plateau based on four grazing intensities,namely,fence grazing,light grazing,moderate grazing and heavy grazing.The results showed that the change of grazing intensity indirectly affected the carbon input and output of alpine grassland ecosystem by disturbing the plant-soil interface,and further affected the carbon balance.Due to grazing history,climate condition,the grassland types and other interference,the response of alpine grassland ecosystem carbon balance to grazing intensity is complicated,so it is necessary to adopt more flexible,specific and targeted measures to grazing management,which is of great signifi-cance to the rational grassland management decisions,and to the stability of the Qinghai-Tibet plateau al-pine meadow carbon balance.