Four adjacent ranges define the western edge of the Avra and Altar valleys. Even though desert ironwood has dark green, lush foliage much of the year, this tree is almost exclusively a Sonoran Desert species. The same is true of the distribution of saguaros, foothill palo verdes, fishhook barrel cacti, and most of the hundreds of other plants growing here. These rugged ranges also provide natural refuges for a variety of wildlife, including desert bighorn and migratory pollinators. In addition to the biological resources, the area has abundant rock art sites and other archaeological sites.
- Geological and Ecological Diversity in the Proposed Ironwood Preserve - Assessing Rock-Soil-Plant-Wildlife Relations in the Silverbell, Ragged Top, Waterman and Roskruge Ranges of Pima County: Sonoran Desert Conservation Plan