The role of browsers in maintaining the openness of savanna grazing lawns

1. In savannas, ruminant herbivores can have divergent impacts on tree recruitment and resulting woody cover. Heavy grazing by cattle results in woody thickening, whereas intensive grazing by wildlife instead tends to be associated with lower woody cover.

2. To disentangle why woody cover is low in areas heavily grazed by wildlife, we tested (I) whether short-grass environments attract indigenous mammalian browsers; (II) whether preference for short grass decreases with browser body mass because of differences in predator susceptibility; and (III) whether these translate into suppression of seedlings and saplings on grazing lawns, thus maintaining their openness.

 3. This work was conducted in Kruger National Park (KNP) and Hluhluwe iMfolozi Park (HiP), South Africa. In KNP, the effect of grass height on browser abundance (estimated using dung counts), and on the utilisation of woody plants by browsers (using a bite-score approach) was tested. An exclosure experiment tested the ef...