Dominant species' dominant role and spatial stability are enhanced with increasing stocking rate

Abstract

Stipa breviflora Grisb. (S. breviflora) is a dominant species in the desert steppe of northern China. Its function and role at the plant community level increases with increasing stocking rate. However, the response of spatial stability remains unclear. We selected treatment areas representing no grazing (CK), light grazing (LG), moderate grazing (MG) and heavy grazing (HG) in a long-term grazing experiment (2004–2017) in a S. breviflora desert steppe in Inner Mongolia, northern China. Using a mechanical sampling method, 40 m × 40 m representative sample plots were selected to obtain the height, coverage and density of the S. breviflora population and community, and we computed the standing crop of mechanical sampling quadrats based on a random sample of cutting quadrats. Analysis of standing crop, density of S. breviflora population and its ratio in the plant community showed that the dominant role of S. breviflora population in the plant community increased with increasing grazing intensity, while the spatial stability of S. breviflora population not only had many dimensions, but also many states. The dimension or combination of dimensions of its stability performance and its adaptive state varied under different disturbance intensities and frequencies.