The wilderness protects habitat that supports the largest herd of Peninsular bighorn sheep in the country. The Bighorn Institute, a non-profit research group established in 1982 by several biologists and veterinarians, estimates approximately 60 adult sheep live in the Santa Rosa Mountains, and a total population of 800 sheep in the Peninsular Ranges north of Mexico. The Peninsular Range bighorn sheep is a subspecies that has been protected since 1971 under the California Endangered Species Protection Act and federally protected since 1998 under the Endangered Species Act. The Peninsular Range bighorn sheep herd utilize the entire range between 1,000 to elevation. Bear Creek, Deep Canyon and Martinez Canyon are important as summer concentration areas and provide the rugged escape terrain necessary for lambing. Besides bighorn sheep, there are also mule deer, bobcat and coyote. Native rare plants in the Santa Rosa Wilderness include shrubs such as Santa Rosa sage, and Nuttall's scrub oak. Perennial herbs include Santa Rosa Mountains leptosiphon, and triple ribbed milkvetch. The rugged terrain is formed by uplifted blocks of igneous and metamorphic rocks situated between two major tectonic fault zones, the San Andreas and the San Jacinto. Perennial streams erode the steep-walled canyons and support large fan palm oases. The Santa Rosa Mountain range and the two faults all trend northwest-southeast and are part of the Peninsular Ranges that extend from Southern California to Baja, Mexico.
Recreation
The Santa Rosa Wilderness joins wilderness areas in the San Bernardino National Forest along its western border and the designated California State Wilderness in Anza Borrego Desert State Park to the south. Recreational activities in the Santa Rosa Wilderness include backpacking, horseback riding, day hiking, and nature study/photography.
The Boo Hoff equestrian trail is one of the few trails in the wilderness that is constructed and maintained by a local equestrian club.
The Cactus Spring Trail which is an ancient aboriginal pathway, links the Santa Rosa plateau with the desert floor in the Coachella Valley. To the west, this trail connects with designated wilderness areas in the San Bernardino National Forest.
Rockhouse Canyon and valley, in the southern wilderness area, has remnants of early Native American and European settlers.
Rabbit Peak, located near the southeastern boundary, is a notable desert peak for its challenging climb to the summit. Local Sierra Club chapters lead organized day and overnight trips to the peak. Universities and local colleges utilize the Santa Rosa Mountains frequently as a living laboratory for scientific and informal studies and outings.
Hunting is restricted to the southem half of the wilderness since the northern portion is located within a State Wildlife Refuge. Deer, quail and dove are hunted in season.