Miller, R.F. & Eddleman, L.L. 1997: Temporal and spatial changes of sage grouse Centrocercus urophasianus habitat in the sagebrush ecosystem. - Wildl. Biol. 3: 273.
Plant species composition, community structure and matrix of plant communities across the landscape determine the quality of hiding and nesting cover, and the season of availability, abundance, and quality of food for sage grouse Centrocercus urophasianus throughout the year. Plant composition and structure at the community and landscape levels vary in time and space and are functions of climate, geology, topography, soils, and disturbance. These factors vary greatly across the vast sagebrush Artemisia region which accounts for the majority of sage grouse habitat. The sagebrush biome also encompasses numerous other vegetation zones, of which some are important and some are not, to the sage grouse life cycle. The variability of this landscape enables sage grouse to move from valley floors to high elevation communities or from semi-arid uplands to wet meadows, following the phenology of succulent forbs during the pre-nesting and brood rearing stages. The variable landscape also provides opportunities for food and cover during winter. Structure, composition, and matrix of plant communities characterizing today's landscapes are unique from any other time period in the past due to a change in disturbance regimes, introduction of exotic species, and land conversion to cropland, urbanization, and mining. These factors, interacting with soils, topography, and a continual change in climate, have shaped the plant communities of the 20th century. Spatial and temporal changes in vegetation across the sagebrush biome are discussed. Focus is placed on: 1) environmental factors which determine spatial change of potential natural flora across and within the different sagebrush types; 2) environmental factors which determine long-term and short-term temporal change in vegetation; and 3) management considerations which influence community structure and food availability for sage grouse.
Key words: Centrocercus urophasianus, habitat, management, sagebrush biome, sage grouse, spatial change, temporal change
Richard F. Miller, Great Basin Experimental Range, Oregon State University, Burns, Oregon 97720, USA
Lee L. Eddleman, Department of Rangeland Resources, Oregon State University, Corvallis, Oregon 97331, USA