Effects of Stocking Rate on a Rough Fescue Grassland Vegetation

Abstract

A study was conducted to examine the effects of 4 stocking rates on the vegetation in a Rough Fescue Grassland vegetation in southwestern Alberta. Stocking at a light rate (1.2 AUM/ha) for 32 years did not affect range condition. However, a modest increase in stocking rate (1.6 AUM/ha) led to a marked decline in range condition. This was associated with a change in the composition of rough fescue from 38 to 21% of basal area. Rough fescue (Festuca scabrella) was nearly eliminated with a stocking rate of 2.4 AUM/ha. Rough fescue was replaced by Parry oat grass (Danthonia parryi) which increased from 24% at 1.2 AUM/ha to 48% at 2.4 AUM/ha. However, stocking at 4.8 AUM/ha resulted in severe deterioration of the grassland. This required annual adjustment of the stocking rate to avoid animal losses. The recommended stocking rate for good condition range in the area is 1.6 AUM/ha. Recovery of the vegetation within the exclosures, from the time of their construction, to a stable range condition, took from 14 years in the lightly grazed field to more than the length of the study in the very heavily grazed field. The duration required for recovery was related to the original range condition of the exclosures.