An Evaluation of Big Game Winter Range in Southwestern Alberta

Abstract

After one growing season of protection there was very little difference in herbage production and composition inside and outside the exclosure. However, by the end of the fourth growing season herbage production inside the exclosure had increased to 2,775 pounds per acre, an increase of nearly 600 percent in only 4 years. Baldgrass, (Sporobolus neglectus Nash.) which had been the dominant species, had decreased to only 8 percent of the total production while little bluestem had increased from almost nothing to 56 percent. Big bluestem (Andropogon gerardi Vitman) and Indiangrass, (Sorghastrum nutans (L) Nash.) had increased from a trace to 17 percent and 11 percent, respectively. In 1956, as now, the glades outside the exclosures were producing about 400 pounds of ovendry herbage per acre, mostly the less desirable baldgrass and black-eyed susan (Rudbeckia hirta L.) with a scattering of the more desirable little bluestem (Andropogon scoparius Michx.) and Indiangrass (Table 1). Herbage production in the nearby Lizzard Pen Exclosure probably reached a peak 5 or 6 years after fencing, but production decreased about 25 percent over the years. Such a decrease is typical of the reaction of any grassland area where the old herbage is not removed periodically. After 21 years of complete protection, herbage production has stabilized, because of continued complete protection, at about 2,150 pounds per acre, 23 percent less than production in the Caney Tower Exclosure. The greatest difference was in production of little and big bluestem, but the significance of this difference was offset to some extent by greater Indiangrass production in the Lizzard Pen Exclosure. Many of southwest Missouri's glade ranges in poor condition could contribute more to the forage resource of the region if they were given 3 or 4 years of complete protection from grazing and moderately stocked thereafter. Complete recovery would probably not be obtained after only 3 or 4 years, but the range should continue to improve under moderate grazing.