Bluebunch Wheatgrass Response to Spring Defoliation on Foothill Rangeland

• Published in: Rangeland ecology & management 2007-09, Vol.60 (5), p.498-507
• Main Authors: Brewer, Tracy K., Mosley, Jeffrey C., Lucas, Daniel E., Schmidt, Lisa R.
• Format: Article
• Language: English
• Subjects: Cattle; Cervus elaphus nelsoni; clipping; Defoliation; defoliation response; dry matter accumulation; elk; Elks; field experimentation; Foothills; forage grasses; Grasses; grazing; Grazing management; height; herbivory; Management decisions; Mountains; overcompensation; Plants; Precipitation; Private property; Pseudoroegneria spicata; Range management; Rangelands; Research s; seasonal variation; Snow; spring; Steppes; Summer; temporal variation; topography; wild animals
• ISSN: 1550-7424; 1551-5028; 1551-5028
• DOI: 10.2111/1551-5028%282007%2960%5B498%3ABWRTSD%5D2.0.CO%3B2

Spring elk grazing may reduce forage availability for wildlife or livestock in summer and may harm forage resources on foothill rangeland. We quantified bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) response to spring defoliation on foothill rangeland in southwestern Montana. Two experiments were conducted simultaneously on a foothill grassland site and a foothill sagebrush steppe site. Bluebunch wheatgrass plants (n  =  800) were selected and excluded from wild and domestic ungulates. Clipping treatments were applied in either early spring (mid- to late April) or late spring (mid- to late May), and plants were clipped to 1 of 3 residual heights (3, 6, or 9 cm) for 1, 2, or 3 successive years. Unclipped plants served as controls. Plant response was measured in late June and late July on both sites. April clipping for 3 successive years did not adversely affect bluebunch wheatgrass in June or July (P > 0.05) at either site. On foothill grassland, May defoliation to 3 cm for 2 consecutive years reduced leaf height (P  =  0.04) in July. May defoliation for 3 successive years to 3 or 6 cm reduced plant yield (P