Winter Foraging Ecology of Greater Sage-Grouse in a Post-Fire Landscape

In the Great Basin, changes in climate and associated fire regimes may alter the density and distribution of shrubs, changing the structure and diet quality of plants in burned areas. We evaluated how the structural and phytochemical characteristics of three-tip sagebrush ( Artemisia tripartita ) relative to Wyoming big sagebrush ( A. tridentata wyomingensis ) influence the winter foraging ecology of Greater Sage-Grouse ( Centrocercus urophasianus ) at a site with a known history of fire in south-central Idaho. Three-tip sagebrush had lower protein content and lower chemical defenses compared to Wyoming big sagebrush. We found that time since last fire over a 30-year history was more strongly correlated with changes in phytochemicals in three-tip sagebrush compared to Wyoming big sagebrush. Despite phytochemical differences, both Wyoming big sagebrush and three-tip sagebrush were browsed relative to their availability. However, within a species, smaller plant height and lower concentrations of phytochemicals, specifically two individual monoterpenes, explained diet selection by sage-grouse. Our results indicate that dietary quality of three-tip sagebrush may provide acceptable forage for sage-grouse in post-fire landscapes where other species of sagebrush have not yet recovered. However, relying on re-establishment of one species of sagebrush without consideration of structural and dietary quality may compromise successful conservation efforts.