Grass species composition and traits
We did not reveal any effect of herbivore abundance and richness on
grass community composition and the traits of the species present. The
only significant result was the effect of hippo and scrub hare abundance
on grass species community composition. Our expectation was that the
grass community composition would be shaped either by the overall
grazing pressure, manifest by the total herbivore abundance or by the
abundances of individual herbivore species. The total grazing pressure
induces different levels of grazing, e.g., overgrazed dry grass
communities with abundant annual species such as Aristida
adscensionis and Tragus berteronianus , heavily utilized grazing
lawns with adapted species such as Cynodon dactylon andBothriochloa radicans , or moderately grazed veld dominated by
tall competitive species such as Themeda triandra orPanicum maximum (van Oudtshoorn 2018). Different abundances of
herbivore species in particular plots may lead to the suppression or
facilitation of certain species and traits via grazing selectivity (Bell
1971) or sward-height specialization (Farnsworth et al. 2002), which is
reflected in traits of individual grass species (Díaz et al. 2007).