Study On Responses Of Inner Mongolia Degraded Grasslands To Different Disturbances

Using field investigation, field experiments, model and simulation methods, we studied the ecological responses of the degraded grassland to grazing, rodents'activities and simulated disturbance in the field, from the aspects of plant diversity, plant functional groups, intraspecific spatial pattern, interspecific spatial association and the developing dynamics of plants on the rodent mounds and new gap. Our results were indicated as follows:(1) Under zero grazing, the vegetation cover was significantly less than under light, medium or heavy grazing, while the three latter had no significant difference each other. After long-term grazing, the dominant plant became Aneurolepidium chinense under zero grazing, but still was Artemisia frigida under light and medium grazing. However, the cover of Carex duriuscula was largest under above three grazing treatments. Under heavy grazing, Potentilla acaulis became dominant and its population cover was largest. With grazing intensities increasing, the population cover of A. frigida first increased, and then decreased, while first sharply increased, then gradually increased, finally sharply increased again for P. acaulis; Diversity and evenness indices were largest under medium grazing, but smallest under zero grazing, which showed that the plant diversity under medium grazing was highest, but lowest under zero grazing. For dominant indices, its changing trend was contrary to the diversity and evenness indices.(2) Grazing has significant effects on spatial patterns of P. acaulis (or Cleistogenes squarrosa) population. The spatial patterns of plant population changed with scale increasing (0-100 cm) even if the same grazing intensity had been experienced; At the small scales, plant population mainly was aggregate; Under the same grazing...