Vegetation trends due to climatic changes are difficult to separate from disturbances caused by varying land uses. To separate climatic influences from livestock grazing and fire disturbances within sagebrush steppe, we compared vegetation structure and productivity during 2 periods (10-year sequences of data from the late 1950s to the late 1960s and 3 years in the early 1990s) at 12 stands within 3 relief areas in or near the Great Rift of southern Idaho. Year-to-vear fluctuations in annual net aboveground phytomass accumulation (ANAPA) were considerable in response to varying climate during both periods...