Climate and grazing are the main drivers of plant community composition and species richness in arid environments. This study aimed to examine the vegetation response to interannual rainfall variability and grazing pressure in Mongolia. To investigate the effects of rainfall variation between 2 years on vegetation spatial patterns along a grazing gradient, two sites were selected as representatives of desert-steppe and steppe zones. The proportions of the different functional groups was affected by grazing pressure and rainfall variability in both desert-steppe and steppe zones. In the desert-steppe zone, species richness was significantly lower in the drier year but did not vary with distance from a settlement (a proxy for grazing pressure). In the steppe zone, species richness varied significantly with grazing pressure but did not vary between years. Thus, precipitation would be more important than grazing pressure in terms of their effects on vegetation changes in dry areas with high variability of rain.