Arid rangelands of the Southwest are fragile, easily damaged by abusive grazing, and subject to frequent droughts. The land resources in western Texas, southern and western New Mexico, and southern Arizona have plateaus, plains, basins, and many isolated mountain ranges. The growing season precipitation occurs during the summer, and the spring period is normally very dry and occasionally windy. The plant resources include the Flourensia-Larrea shrub savanna, the Bouteloua-Hilaria  prairie, the Bouteloua-Hilaria-Larrea shrub steppe, the Larrea-Flourensia association, the Bouteloua-Hilaria steppe, and the Larrea-Franseria association (Kuchler 1964). Pronghorn antelope and a number of rodents and rabbits occur throughout the area.