A number of studies has addressed that , the inhabitation of rats and insects , further inhibit the growth of grass in degenerate grasslands. However , several rodents have been shown to increase biodiversity (Yoshihara , 2010). In Mongolia , the number of livestock populations has undergone significant changes due to changes in the economic system from 1991 to 1992 . Moreover, grassland degradation is remarkable in the riverside used by nomadic livestock in Mongolia . The purpose of this study was to evaluate the distribution of Brandt’s voles (Lasiopodomys brandtii : Microtus brandtii) and the modification of vegetation by Brandt’s voles . Experiments were conduted　from the summit of nature reserve to the riverside pasture buffer zone to clarify limiting factor of distribution of voles in degenerate grassland . In conclusion , the present study had demonstrated that in the landscape scale , Brandt’s voles inhabits the areas with strong artificial influence . Moreover , plant diversity increased on the Brandt’s voles colony .