Motte Rimrock UCR Natural Reserve (c) UCR / Ilse Ungeheuer

Motte Rimrock Reserve

Motte Rimrock Reserve / Photo by Mark Chappell
Motte Rimrock Reserve / Photo by Mark Chappell

The Motte Rimrock Reserve lies on a broad, rocky plateau at the western edge of Perris Valley. It contains rich archaeological resources, including some of the best-preserved pictographs in Southern California. Coastal and desert influences intermingle at the site, creating an unusual mix of habitats. An inland type of coastal sage scrub covers most of the reserve, with other areas supporting chaparral, coastal-desert transitional grassland, and riparian thickets. Six seasonal springs add to the diversity of the landscape. The reserve protects critical habitat for a variety of animals, including two federally listed species: the endangered Stephens’ kangaroo rat (Dipodomys stephensi) and the threatened California gnatcatcher (Polioptila californica), plus ten more rare animal species.

Special Programs

  • Management and monitoring of Stephens’ kangaroo rat.
  • Long-term hummingbird migration monitoring site.

Public Outreach

Site visited by high school science classes.

Field Courses

Site visits by university courses in anthropology, plant taxonomy, field ecology, bird banding, archaeology, and others.

Selected Research

  • Several major studies on birds, reptiles, amphibians, and mammals in coastal sage scrub habitat.
  • Habitat requirements of California gnatcatchers.
  • Comparative studies of rock-art sites in California and the Great Basin.
  • Genetic and fitness consequences of coastal sage scrub seed transplantation.
  • Demography and effects of fragmentation of coastal sage scrub habitat on rufous-crowned sparrows.

Special Research of National Significance

Physiological, Demographic, Competitive and Biogeochemical Controls on the Response of California’s Ecosystems to Environmental Change.


Contact Information

Kenneth J. Halama
Biology Department
1208 Spieth Hall
University of California
Riverside, CA 92521
Motte Rimrock Reserve website


Riverside County, 1.6 km (1 mi.) northwest of Perris; 24 km (15 mi.) south of Riverside campus.


On-site housing/kitchen facilities for up to 14 people; campground for up to 30 people; wet lab; library/storage area; 260 hectare (642 acre) transect grid; bird-banding station; marked trails and dirt roads; weather-recording station.

Reserve bibliography

The reserve bibliography includes citations of journal articles, books, theses, art, and other works published about or based on activities conducted at the reserve.

Motte Rimrock Reserv Bibliography


Functional geographic information system (GIS); animal records since 1971; synoptic collections; bibliography of on-site research; photographic archive; users handbook.

Plant List


Reserve director, steward.


289 hectares (715 acres)


482 – 605 m (1,580 – 1,985 ft.)

Average Precipitation

33 cm (13 in.) per year.

Average Temperatures

July maximum: 37 ºC (98 ºF)
January minimum: 2 ºC (36 ºF)




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