The relationships between structure and function of plant communities in the desert steppe.

Background: Assessing the relationships between spatial and temporal structures and functions of plant communities is an effective way to understand the changing dynamics of plant communities in specific environments. In this study, we investigated the response of structural and functional stabilities of plant communities to stocking rate in the desert steppe over a 16-year grazing period as the research background.

Methods: We used classical statistical methods to investigate the quantitative characteristics of plant communities over time (2014-2019) and space (2017-2019) at four stocking rates (control, CK, 0 sheep·ha^-1·month^-1; light grazing, LG, 0.15 sheep·ha^-1·month^-1; moderate grazing, MG, 0.30 sheep·ha^-1·month^-1; heavy grazing, HG, 0.45 sheep·ha^-1·month^-1) in the Stipa breviflora desert steppe of Inner Mongolia. We then examined the relationship between structural and functional stability of plant communities.

Results: On the spatial scale, the structural stability of plant community was the highest in the LG treatment and the lowest in the MG treatment. The functional stability of plant community was the highest in the MG treatment and the lowest in the HG treatment. On the temporal scale, the structural stability of plant community was the highest in the MG treatment and the lowest in the LG treatment. The functional stability of plant community was the highest in the LG treatment and the lowest in the HG treatment. Affected by the stocking rate, the structural stability of plant community fluctuated more widely on the spatial scale and its functional stability varied more widely on the temporal scale. Nonetheless, the functional stability of the plant community is more responsive to the stocking rate.

Conclusions: Our findings suggest that influenced by the disturbance of stocking rate, the structural stability of plant community is more significant than the functional stability in the desert grassland ecosystem, which lays a solid foundation for the study of ecosystem stability.