Change, an inherent characteristic of ecosystems, is a recognized feature of vegetation in the arid and semiarid portions of the southwestern United States. Territorial surveys in the 19th century and terrestrial photography in the 19th century and early 20th century have been used to establish a base for vegetation conditions and then for recording variations from this base. All evidence indicates a dramatic shift from land with a high proportion of grassy vegetation to one dominated by shrubs. Most of these changes have occurred in the last 50-100 years. Following are some of the reasons and possible solutions to problems resulting from these changes that would be applicable to parts of Arizona, New Mexico, and Texas, with possible use in other arid and semiarid regions of the world.