Research progress of the grassland carbon cycle and grassland degradation in China

Abstract

Grasslands, one of the most common vegetation types in the world, account for nearly 20% of the global land surface. The vast land cover and carbon sequestration potential make it become the important composition of the terrestrial carbon cycle. In China, grasslands mainly locate in the arid and semi-arid areas in the northwest and the Tibetan Plateau alpine climate regions, which make it sensitive and vulnerable to climate change and frequent human intervention. Along with the global warming and population explosion, substantial land-use and cover change has occurred in China due to overgrazing, grassland reclamation, and over-mining explorations. All these changes had led to serious ecological problems, such as grassland degradation, desertification, and future changes of the global carbon cycle. In recent decades, Chinese government has initiated several ecosystem restoration programs to mitigate the environment degradation. Meanwhile, along with the development of remote sensing technology, grassland carbon sequestration can be simulated by ecological remote sensing model in large scale, and previous studies showed that grassland of China is carbon sink. Grazing is one of the main ways of grassland resource utilization and is also the main factor of grassland degradation. About 35% of the degraded grasslands in the world are caused by overgrazing, which accounts for more than 20% in China. However, the spatial–temporal dynamic of carbon sink or source of grassland of China, and the driving mechanism of grassland degradation in China need deep analysis.