Experimental evidence that heavy grazing causes fragmentation of Stipa breviflora in a desert steppe

We aimed to investigate how heavy grazing influences the population dynamics of Stipa breviflora with a specific focus on changes in density and spatial distribution. We measured Stipa breviflora density, basal diameter, and distance between plants in each quadrat and found: (1) The density of Stipa breviflora under no grazing was 56.05 % lower than that under heavy grazing( P < 0.05); (2) No significant difference was showed on the total basal area of Stipa breviflora between heavy grazing and no grazing treatments, but the average basal area of individuals heavy grazing was 51.32 % lower than no grazing ( P < 0.05). (3) The euclidean distance between individuals, and the number of seedlings were both 4.04 % and 78.79 % under heavy grazing lower than no grazing, respectively. Overall, we suggest that the increased density of Stipa breviflora under heavy grazing was caused by fragmentation.