Bowers measured plant species composition and cover in plots exposed to varying levels of herbivory (no grazing, small rodent grazing, small mammal grazing, and deer grazing) for four years in a pasture recently returned to the recolonizing state by mechanical disturbance. Species composition, cover, and frequency of occurrence varied by year and level of herbivory. Individual plant species responded to herbivory by increasing, decreasing, or maintaining cover within plots. Plots exposed to intermediate levels of herbivory had the greatest species richness and diversity, whereas plots with limited or excessive grazing had low species richness and diversity. Herbivory was a major factor determining species composition in this pasture and may affect plant succession as this pasture recolonizes from previous disturbance.
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