Distribution of carbon and nitrogen in sagebrush steppe after six years of nitrogen addition and shrub removal

Widespread loss of sagebrush (Artemisia tridentata) in much of the western US represents a major shift in the dominant species type and may trigger changes in ecosystem characteristics such as the distribution of nutrients. We examined total nitrogen (N) and carbon (C) content of soils directly below and away from Wyoming big sagebrush (A. tridentata ssp. tridentata) canopies in undisturbed areas, where shrubs had been removed for six years, and in areas that have received annual additions of nitrogen, to improve our understanding of the effects of shrub canopies and perturbations on nutrient distribution. Soils below shrub canopies had more C and N than soils in open interspaces; resource islands were still present six years after shrubs were removed. Soil carbon content in the top 10cm was 25% greater on shrub removal plots than on control plots. There was no difference in total N or C on plots that received annual additions of N when compared to control plots. (c) 2007 Elsevier Ltd. All rights reserved.