Changes in soil nutrients, vegetation structure and herbaceous biomass in response to grazing in a semi-arid savanna of Ethiopia

► Lightly grazing had a higher herbaceous diversity, abundance, basal cover and biomass, and a lower bare ground than heavy grazing. ► Grazing pressure had no effect on the density and number of woody species, and on the proportion of encroaching woody species. ► Light grazing sites had higher soil nutrients due to higher basal cover and biomass than heavy grazing. ► Changes in herbaceous vegetation, standing biomass and soil compositions are caused by interactions between grazing, soil and vegetation. ► The interactions of vegetation and soil under influence of grazing determine the transitions of semi-arid savannas.