<P> Trees of the savanna include a juniper - oak mix and a mesquite - acacia mix scattered over fairly short grasses , which traditionally were affected by droughts and regular fires . Some pecan trees are found near the springs and rivers . The Balcones Fault is associated with the Edwards Plateau formation . This fault line is an ecological demarcation for the range definition of a number of species . For example , the California fan palm , Washingtonia filifera , is known to occur only west of the Edwards Plateau or Balcones Fault , and Buddleja racemosa is known only from the southern edge of the plateau . </P>
how have the physical features of the edwards plateau limited human activities in the region
affected by droughts and regular fires