One of the largest biomes in the continental United States, the semi-arid rangeland, has been dramatically altered by human activities over the past 150 years. The most widespread and conspicuous vegetation change has been the expansion of woody plant at the expense of grasses, sedges and forbs. This research will explore the following general questions in the montane meadows of the Sierrra Nevada where the expansion of sagebrush has occured: 1) Are any ecological processes that can explain the current patterns of sagebrush and herbs? 2) What are the current trends of change in these communities and 3) What are the barriers to the recovery of the herbaceous species? This will be done with a combination of experimental and observational studies to examine the interactions between sagebrush and herbaceous species. The experiments will involve large cattle exclosures, smaller gopher exclosures, removal of vegetation (clipping) and water manipulations. In addition, experiments will also be conducted in a series of meadow restoration plots that are in their initial stages of establishment. These experiments along with the detailed observational studies will enable the PI to elucidate the factors that constrain herbaceous species within the expanding sagebrush community. It is hoped that not only will the proposed research contribute a solid ecological framework to current restoration plans for this system, but it also will help address the more widespread problem of using general ecological theory to site-specific restoration issues.
