Soil types are typically better suited for growing plant material near the streams and rivers because of the higher quality of soil deposited from the water.  We can see the areas in the Landsat TM images where there both ephemeral and continuous stream flow throughout the preserve.  These correspond with different soil types.  However, upland soil types, shown as pinks and purples in the soil map, tend to be more susceptible to grazing pressure.  Upland soil types dry out quickly leaving it hard to support forage growth.  From these images it is easy to distinguish the soil types and areas of higher moisture within the soils.