<b>The disturbance of soil carbon and nitrogen in big sagebrush ecosystems after mastication</b>

Big sagebrush <i>(Artemisia tridentata </i>Nutt.<i>) </i>is the dominant plant species in sagebrush steppe ecosystems across western North America. Similar to other dryland shrub-dominated ecosystems, larger soil carbon and nitrogen pools are found underneath big sagebrush plants in elevated mounds of soil called hummocks than in the interspaces between shrubs. This dynamic creates an “island of fertility” effect that produces spatial heterogeneity within these ecosystems, with under-shrub microsites having more soil carbon and nitrogen than interspace microsites. Shrub removal practices, including mastication, are commonly used to increase grass forage for livestock and wildlife. We examined the effects of mastication on soil carbon and nitrogen pools and spatial distribution, using treated sites with paired controls. At each site, we measured the height of hummocks and took soil samples from under big sagebrush individuals (live and dead) and in the interspace (under perennial grass and bare ground).