Hunting leases for deer, quail, mourning dove, wild turkey, and javelina are an important source of income. The major concern of management is controlling brush that invades the grasslands. On hills and in plateaus it ranges from 400 to 1,200 m, increasing gradually from east to west. Valleys are narrow to broad and have gently sloping to steep walls and smooth to undulating floors. Hills are sloping to very steep.
Plateaus are broad and nearly level to undulating.
Average annual precipitation -375 to 750 mm. About three-fourths of the precipitation falls during the growing season. In the western part rainfall is adequate for range grasses but inadequate for cultivated crops, and in the central and eastern parts rainfall is marginal for both. High temperatures and high evaporation and transpiration rates in summer limit crop production. Only a few rivers and streams flow throughout the year.