This study is designed to generate predictions about the density, spatial arrangement and cover of obstructions to wind and water necessary to promote grass recovery in
shrub-dominated plant communities in the northern Chihuahuan Desert. Specifically, we would like to "(a) to understand the density of vegetation regrowth in intershrub areas(such as we have seen as a result oi last summer) necessary for it to become self-sustaining and engender grass recovery in shrub-dominated plant communities and b) the extent to which we might trigger such regrowth through the use of artificial barriers to resource and propagule movement". The objectives are to determine extent to which physical obstructions capture soil and litter (plant scale), and the extent to which they modify resource and propagule movement at the patch scale. We will also document changes in plant cover at both plant and patch scales.