SHRUB ENCROACHMENT ENHANCES CARBON STORAGE AND PLANT DIVERSITY IN THE DESERT STEPPE ECOSYSTEM.

Shrub encroachment onto grassland is a global problem, and thus the relationship between shrub encroachment and grazing disturbance needs to be clarified. In this study, we set up two treatments in China's desert steppe, including no grazing (CK) and heavy grazing (HG). We aimed to analyze the impact of grazing on carbon storage in shrublands and herbaceous communities. We utilized Real-Time Kinematic Positioning (RTK) and ground-penetrating radar (GPR) to detect and quantify aboveground / belowground biomass of Caragana microphylla. We also measured the biomass of grass. The resulting model for the aboveground biomass of C. microphylla was y = 22.45e4.5562x, where x denotes the canopy area (R² = 0.96). The resulting model for the root biomass of C. microphylla was y = 3×10-5x - 23.618 (R² = 0.99), where x is amplitude. The coarse root / shoot ratios of the shrub were 8.06 and 8.92 in the CK and HG treatments, respectively. Heavy grazing significantly reduced the density and biomass of both C.microphylla and the broader community (shrub + grass) (P<0.05). The carbon stock of vegetation was significantly greater in shrubby grassland than in Stipa breviflora grassland (P<0.05). Our results show that shrub encroachment increased carbon storage and plant diversity in the desert steppe, while, at the same time, heavy grazing affect the shrub encroachment by C. microphylla. [ABSTRACT FROM AUTHOR]