In June 1999, only one mound had just one survivor, almost half of the mounds had four or more survivors. These were recaged with taller wire cages in spring 1999 to increase growth. Survivors by treatment are shown in Table 2-2. Mortality was very low this year despite the very low rainfall Table 2-2. The mounds provided an immediate improvement in habitat diversity and many organisms have colonized the mounds.
Most mounds have multiple burrows although the mounds with mesquite are more heavily populated.
Determining which animal, insect, lizard or snakes uses a hole can be difficult, and no detailed assessment has been done. The burrowing mammals were probably responsible for some if not most of the mortality of plants on some mounds. Birds have also been observed sitting on the mesquite. It is clear that the mound topography and mesquite has adding richness to the once flat and largely barren borrow pit. There was a decline in burrows from 1998, probably as a reflection of the serious drought.