We explored the feeding ecology of ungulates in two contrasting arid systems in South Africa, arid savanna of the Kalahari and arid dwarf shrublands of the Nama Karoo. Historically, these arid systems of southern Africa had large migratory herds of indigenous ungulates, having a profound influence on the ecological functioning of these systems. These migratory habits have been largely disrupted, predominantly through anthropogenic disturbances. With the erection of fences and the introduction and confinement of livestock, a change in vegetation species composition has occurred. As both systems within this study consist of reclaimed farmland, improved understanding of ungulate diet requirements is needed. Fresh dung samples were collected from both systems during three seasons, early wet, late wet and dry seasons. Stable carbon isotope analysis of these dung samples was used to determine relative proportions of C3 and C4 plant forms within the ungulates’ diet on a seasonal basis. Provisional results indicate differences in diet composition for some of the species between the two systems. Some of these differences may relate to differences in relative abundances of plant growth forms available for forage selection, and the ability of ungulates to tolerate such plant diversity within their diets.