The structure and species composition of vegetation in grazing ecosystems have been formed as a result of the evolutionary and mutual relationship of different animal groups with each other and the vegetation within a long period of time.Herbivores with a variety of body sizes (including both. vertebrates and invertebrates) have interactive effects on each other through the vegetation in their common habitat, The impact of such relationships on the vegetation is still one of the subjects of interest by the ecologists. In this study, the importance of seed harvesting ants ( Messor species ) and Persian gazelle ( Gazelle subgutturosa ) on the vegetation and soil seed bank in rangeland habitats of Kolah Ghazi National Park were investigated.15 active ant nest sites established besides the gazelle droppings accumulation sites (gazelle presence- ant presence sites) were chosen and then in the closest distance to each location, one ant nest site without gazelle droppings accumulation site in the surrounding (ant presence- gazelle absence sites) and a gazelle droppings accumulation site without any ant nest site around it (gazelle presence- ant absence sites) were selected (totally 15 sites for each combination of gazelle and ant presences). Vegetation was studied inside and outside of each site using a 25×25cm plots. A pooled soil sample was taken from each site to investigate the soil seed bank composition in the greenhouse. Totally, 61 plant species belonged to 19 different families and 60 different genera were recorded in the vegetation plots of sites and the relevant surrounding areas. The total vegetation cover, and the relative frequency of annual and also forb species at the gazelle presence- ant presence sites were significantly higher than those of the droppings accumulation sites. Specie richness and the relative frequency of graminoid species at the droppings accumulation sites were significantly higher than those of gazelle presence- ant presence sites. Meanwhile, the results of DCA analysis indicated that vegetation species composition in droppings accumulation sites is different from those of gazelle presence- ant presence sites. In germination experiments at the greenhouse for 6 months, 4,625 seeds from 120 cultivated soil samples germinated which belonged to 69 plant species from 24 families and 59 genera. The relative frequency of forb species in gazelle presence- ant presence sites was significantly bigger than the same for the mere droppings accumulation sites or mere ant nest sites, : this is while the total density, specie richness, and the relative frequency of graminoid species in soil seed bank of mere droppings accumulation sites were higher. On the other hand, the results of DCA analysis showed the different species composition of soil seed bank in different sites of presence of the two animal groups (one or both). In conclusion, the effect of activities of both animal groups (e.g. ant nest and/or gazelle droppings accumulation sites) on the vegetation and soil seed bank are obvious, while such effect is different. Meanwhile, the joint effect of both animal groups on the vegetation and soil seed bank is different from their independent effects. Considering the dry climate of the studied ecosystem, both animal groups therefore play a major role in the structure and composition of vegetation and specially the seed storage of plant species in the soil, which is essential for their cycle of life. The result of this study presents the ecological importance of different animal groups in dry regions ecosystems, especially relating to the soil seed bank and vegetation dynamics, which may be applied in the management of protected ecosystems and rangeland habitats of the country. Keywords: grazing ecosystems, herbivores, soil seed bank and vegetation dynamics, species composition, germination experiments.