A COMPARISON OF UNGRAZED AND LIGHTLY GRAZED STIPA–BOUTELOUA PRAIRIE IN SOUTHEASTERN ALBERTA

A comparison of ungrazed and lightly grazed Stipa–Bouteloua prairie was made at Manyberries, Alberta. Basal area of the vegetative cover; yields of green grasses and sedges, green forbs and shrubs, fresh mulch, humic mulch; and amounts of underground plant material were determined. Leaf height and basal diameter of Stipa comata were also measured.Protection from grazing favored a Stipa–Bouteloua type of cover that produced greater amounts of dry matter of surficial and underground plant material. Light grazing resulted in a Bouteloua–Stipa type of cover that was less productive. Stipa comata plants on lightly grazed sites were shorter than those on protected sites.Light grazing had an ecological influence upon plant composition that favored the short-grasses over the mid-grasses. Favorable climatic conditions, also, influenced secondary ecological succession.