Grazing effect on grasslands escalated by abnormal precipitations in Inner Mongolia

1. Grazing effects on arid and semi-arid grasslands can be constrained by aridity. Plant functional groups (PFGs) are the most basic component of community structure (CS) and biodiversity & ecosystem function (BEF). They have been suggested as identity-dependent in quantifying the responses to grazing intensity and drought severity. Here we examine how the relationships among PFGs, CS, BEF, and grazing intensity are driven by climatic drought. 2. We conducted a manipulative experiment with three grazing intensities in 2012 (non-drought year) and 2013 (drought year). We classified 62 herbaceous plants into four functional groups based on their life forms. We used the relative species abundance of PFGs to quantify the effects of grazing and drought, and to explore the mechanisms for the pathway correlations using structural equation models (SEM) among PFGs, CS, and BEF directly or indirectly. 3. Grazers consistently favored perennial forbs (e.g., palatable or nutritious plants), decre...