Grazing lawns and overgrazing in frequently grazed grass communities

Frequent grazing can establish high forage value grazing lawns supporting high grazer densities, but can also produce overgrazed grass communities with unpalatable or low grass basal cover, supporting few grazers. Attempts to create grazing lawns via concentrated grazing, with a goal to increase grazer numbers, are thus risky without knowing how environmental conditions influence the likelihood of each outcome.
We collected grass species and trait data from 33 frequently grazed grass communities across eastern South Africa (28 sites) and the Serengeti National Park, Tanzania (5 sites), covering wide rainfall (336–987 mm.yr-1) and soil (e.g. 44–93% sand) gradients. We identified four grass growth forms using hierarchical clustering on principal components analyses of trait data, and assessed trait-environment and growth form-environment relationships using fourth corner and principal components analyses.
We distinguished two palatable grass growth forms that both attract yet resist graze...