Effects of grazing intensity on the spatial distribution of Stipa breviflora population

In this study, the multi-fractal characteristics of the spatial distribution of Stipa breviflora in desert steppe with four grazing intensities are discussed. The four grazing treatments were control area of no grazing (CK), light grazing (LG), moderate grazing (MG), and heavy grazing (HG), with stocking rates of 0, 0.93, 1.82, and 2.71 AUM per hectare per half year, respectively. Based on the box plot and multifractal research methods, the following results indicate that under different grazing intensities, the spatial distribution of the S. breviflora population shows multifractal characteristics. With increasing grazing intensities (except for light grazing), the multifractal complexity of the spatial distribution of S. breviflora population decreases, the niche width almost did not change, the spatial distribution changes from an aggregation state to a uniform state, and the competition intensity among individuals increases. The multifractal characteristics of the spatial distribution of S. breviflora population are the most complex under light grazing: the niche width decreases, the spatial distribution aggregation characteristics are the most obvious, and the competition intensity among individuals is the lowest. Regardless of how the grazing intensity changes, the dominant position of the S. breviflora population in the plant community did not change, and the overall spatial distribution was dominated by the large probability subset.