Regrowth of Festuca hallii (Vasey Piper) and Stipa curtiseta [(A.S. Hitch.) Barkworth] following defoliation on a hummocky landscape in Central Saskatchewan
A 4-year study was conducted on the Missouri Coteau in the Mixed Grassland Ecoregion of Saskatchewan to determine the effects of mowing to a 7.5 cm stubble height on the growth of Festuca hallii (Vasey) Piper and Stipa curtiseta (A.S. Hitch.) Barkworth. Green standing crop (GSC), dead standing crop (DSC) and above ground net primary production (ANPP) were compared to an unmowed control after a single mowing in April, May, June, July, August, September, October or November on 5 landforms including north aspect-concave-slope, north aspect-convex-slope, south aspect-concave-slope, south aspect-convex-slope and level upland. Mowing reduced GSC, DSC and ANPP with reductions varying among months of mowing and among landforms. Green standing crop, DSC and ANPP of F. hallii were greatest on the north aspects and least on south aspect-convex slope and ranged from 2 to 122 g m-2, 3 to 121 g m-2, and 8 to 122 g m-2, respectively. Mowing reduced GSC of F. hallii for 1 to 11 growing season months and DSC for 1 to >11 growing season months. Mowing in May or November reduced ANPP of F. hallii for 1 growing season, while mowing in other months reduced ANPP for 2 growing seasons. Green standing crop of S. curtiseta, ranging from 3 g m-2 to 55 g m-2, was least on the north aspects and greatest on the south aspect-convex slope and was reduced 1 to 5 growing season months following mowing. Mowing after June reduced DSC of S. curtiseta(5 to 58 g m-2) for 1 to 10 growing season months, and ANPP (6 to 64 g m-2) for 1 growing season. Generally, mowing reduced GSC, DSC and ANPP of F. hallii longer than S. curtiseta. Production of F. hallii- and S. curtiseta-dominated plant communities in the Northern Mixed Prairie will be maintained by providing rest periods between defoliation events based on the number of growing season months for F. hallii to recover production.
Mixed Grass Prairie, mowing, western porcupine grass, rough fescue, range management
Master of Science (M.Sc.)