Changes in ecosystem carbon stocks following grazing exclusion in arid and semiarid grasslands

Grazing exclusion (GE) is widely considered to be an important strategy for restoring overgrazed grasslands and promoting carbon (C) storage. However, the changes in the components of ecosystem C with GE and their related drivers remain largely unexplored.
Here, we investigated the effects of GE on the ecosystem C components (plant and soil C) and their key driving factors through sampling inside and outside 15 grazing exclosures across the Inner Mongolia arid and semiarid grasslands in northern China.
Our results showed that, except for dead root C, GE significantly promoted plant C stocks. The increase in AGB and litter C stocks resulted from the accumulation of both biomass and C concentration, while the increase in live root C stock was mainly attributed to biomass accumulation. In contrast, although the topsoil soil C concentration (0-20 cm) showed a marginal increase following GE, its bulk density greatly declined, which resulted in little change in the soil C stocks. Overa...