Soil microbial communities and nitrogen associated with cheatgrass invasion in a sagebrush shrubland

Abstract

Cheatgrass invasion of Intermountain sagebrush steppe in the Western US poses increasing challenges to the function and survival of this native ecosystem. The invasive success and persistence of cheatgrass has been attributed to its physiology, phenology, and recently to increases in soil nitrogen levels. We investigated whether cheatgrass invasion of sagebrush/native bunchgrass communities elevated soil ammonium and nitrate levels, and resulted in soil microbial community diversity and composition changes. Our results did not reveal an increase in nitrogen ions, but showed a shift in soil microbial communities towards bacterial functional groups that can promote nitrogen accumulation in cheatgrass invaded communities.