Conversions from grasslands to shrublands have occurred throughout arid and semiarid regions globally over the past several centuries. Although a number of factors have been implicated as drivers of this conversion (e.g., grazing by livestock, drought, climate change), the key drivers responsible for vegetation change in any particular location are controversial. This controversy is due in large part to the large spatial variation in shrub invasion success through time. At the Jornada Experimental Range in southern New Mexico, we are taking a multi-scale approach to understanding and forecasting landscape scale dynamics associated with these desertification processes. As part of our approach, we are developing a spatially interactive model that simulates interactions and feedbacks between the vegetation, soil properties, and aeolian transport to explain and forecast vegetation dynamics at multiple spatial scales.  Dynamic vegetation patches vary in size and composition that affect fetch and hence erosion and deposition of soil particles by wind. Wind speed data is given using a Weibull distribution derived from empirical data. Preliminary results show that aeolian transport is a key driver of conversions from grasslands to shrublands that depends on spatial characteristics of soil texture and vegetation.