Seed dispersal in the dung of large herbivores: implications for restoration of Renosterveld shrubland old fields

Species-rich, winter-rainfall, microphyllous Renosterveld vegetation in the Western Cape Province of South Africa has largely been transformed for production of wheat and wine. Remaining fragments thus have high conservation value. Abandoned old fields adjacent to natural vegetation fragments could potentially be restored as corridors and habitat for indigenous flora and fauna. We hypothesised that indigenous antelope maintained in a matrix of natural vegetation and abandoned field could play a role in restoration of Renoserveld via seed dispersal.We collected dung of indigenous ungulates in an abandoned field at various distances from natural Renosterveld vegetation, in order to assess the potential of large herbivores to contribute to restoration of plant diversity through seed dispersal. Emerged seedlings from the collected dung represented 29 forb, 13 grass, four sedge, four geophyte and one shrub species. The most abundant emerging seedlings were lawn grass Cynodon dactylon (38%), alien pasture grasses (31%) and indigenous geophyte Romulea rosea (12%). Whereas seeds of annual forbs and grasses were dispersed, only one shrub species was dispersed at very low density. We concluded that large herbivores could retard the rate of recovery of Renosterveld vegetation because viable seeds of herbaceous plants, particularly alien annual grasses and lawn-grasses were more abundant in the dung than the shrub, geophyte or perennial tussock grass species that characterise this vegetation type.