Response of Western Thatching Ant (Formica obscuripes) Colonies to Mechanical Shrub Crushing and Livestock Exclusion in a Wyoming Big Sagebrush (Artemisia tridentata wyomingensis) Community

In 2003, the Bureau of Land Management Challis Field Office implemented a project to evaluate methods to restore the herbaceous understory of a Wyoming big sagebrush (Artemisia tridentata wyomingensis)/bluebunch wheatgrass (Pseudoroegneria spicata) community. Management treatments included mechanical shrub crushing, livestock exclusion, and seeding native bunchgrasses. Experimental units were sampled in summer 2003 prior to treatment and in 2 years following treatments (2005 and 2007) spanning 4 growing seasons. The mechanical shrub crushing was intended to substantially reduce sagebrush cover which could have negative consequences on thatching ant colonies. This report presents the responses of thatching ant colonies to the treatments.