Species richness, as a term that have implicated a number of species and specimens number of every species in a community, is one of the most important evaluation indices to quantity plants in rangeland ecosystems. This case study tries to evaluate the effect of different utilization levels on species richness in Saral. Therefore three areas (Reference, Key and Critical region) were determined for this evaluation. Then species richness data were collected by Whittaker plot in ten replications for any region and these data were analyzed by factorial experiment. Finally treatment mean (plot size and three declared area) were compared by Duncan’s multiple range test. Results show that there are significant differences between treatments mean plot size and reference, key and critical regions in P<0.01 but interaction effects (area × plot size) don’t have a significant difference.
