Grazing reduces the temporal stability of temperate grasslands in northern China

Abstract

Grazing activity can profoundly influence grassland plant community structure and ecosystem functions. However, our understanding of the effects of livestock grazing on ecological stability across different grassland types remains limited. Based on a 5-year investigation along a precipitation gradient (180 mm in desert steppe, 282 mm in typical steppe and 375 mm in meadow steppe) in temperate grasslands of Inner Mongolia, we examined the responses of the temporal stability of plant community aboveground biomass to grazing intensity at three levels (light grazing, moderate grazing and heavy grazing). We found that grazing intensity at all levels reduced biomass temporal stability across all types of grasslands. Heavy grazing intensity reduced community biomass, species richness and species asynchrony. Structural equation modeling further revealed that grazing decreased community stability mainly by decreasing species asynchrony. In addition, community-level stability was driven by grass species stability in the meadow steppe, but it was affected by the stability of forb species in the desert steppe. These findings suggest that grazing practices may alter the stability properties of grassland plant communities, highlighting the importance of understanding changes in different plant functional groups for predicting community dynamics under grazing management.