Greater sage-grouse (Centrocercus urophasianus) habitat in central Montana
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Date
2006
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Montana State University - Bozeman, College of Agriculture
Abstract
Greater sage-grouse (Centrocercus urophasianus) habitat was studied in central Montana primarily on Wyoming big sagebrush (Artemisia tridentata wyomingensis) dominated rangeland. The primary objective was to compare shrub and herbaceous parameters within (use, random or non-use) and between seasonal habitats (nest, brood, winter). Nesting occurred in areas with greater total shrub cover (15v13%) and height (28v26 cm), and taller live (12v11 cm) and residual grass (9v8 cm) than randomly available. The shrubs under which hens nested were taller (50v44 cm) and more productive (61v51 g) than random shrubs. Due to increased precipitation in 2005, total herbaceous (18v13%), grass (15v12%), and forb cover (7v3%), and live grass height (13v10 cm) were greater in 2005 than 2004. Brood and paired random sites were similar for all parameters. There was greater shrub height (29v25 cm), total herbaceous cover (19v16%), forb cover (15v13%), and live grass height (17v11cm) in 2005 than 2004. Shrub density (1.5v1.1/m2) and residual grass height (9v5 cm) were greater in 2004.
Both winters were mild as no month had > 20 cm total snowfall. Shrub height was greater at winter non-use sites than use sites in 2005 (36v32 cm), but similar in 2004 (27v27 cm). Shrub height was different between years. Despite mild winters, shrub cover (12v10%) and density (1.2v0.8/m2) were greater at winter use sites than non-use sites although residual grass height (19v18 cm) and cover (13v14%) were similar. Winter use sites had less shrub cover than nest sites (12v15%). The nest and brood habitat and winter and brood habitat had similar shrub cover, density, and height. Herbaceous vegetation was more important during nesting and brood rearing than in winter. Some portions of grouse habitat may benefit from management for greater herbaceous cover, but never at the sake of less sagebrush. Sagebrush cover from 5 to 36% was the most consistent component of sage-grouse habitat. The differences between cover for nesting (15%), brood (14%), and winter (12%) were small. Therefore, any manipulation attempting to improve one seasonal habitat would impact the others.
Both winters were mild as no month had > 20 cm total snowfall. Shrub height was greater at winter non-use sites than use sites in 2005 (36v32 cm), but similar in 2004 (27v27 cm). Shrub height was different between years. Despite mild winters, shrub cover (12v10%) and density (1.2v0.8/m2) were greater at winter use sites than non-use sites although residual grass height (19v18 cm) and cover (13v14%) were similar. Winter use sites had less shrub cover than nest sites (12v15%). The nest and brood habitat and winter and brood habitat had similar shrub cover, density, and height. Herbaceous vegetation was more important during nesting and brood rearing than in winter. Some portions of grouse habitat may benefit from management for greater herbaceous cover, but never at the sake of less sagebrush. Sagebrush cover from 5 to 36% was the most consistent component of sage-grouse habitat. The differences between cover for nesting (15%), brood (14%), and winter (12%) were small. Therefore, any manipulation attempting to improve one seasonal habitat would impact the others.