Joshua Trees

The Desert Biome

The Mojave Desert is a region of more than 25,000 square miles, and occupies portions of the states of Nevada, Arizona, Utah and California in Western North America.  On the northwestern boundary it extends from the Sierra Nevada range to the Colorado Plateau in the east; it abuts the San Gabriel-San Bernardino mountains in the southwest. Near the Great Basin-Mojave border lies Death Valley, the lowest point in North America and a national park.

The Mojave's desert has extreme climate variation in daily temperature and an average annual precipitation of less than 5 inches. Almost all the precipitation arrives in winter. Freezing temperatures occur in winter, while summers are hot, dry and windy.

The Mojave has a typical mountain-and-basin topography with sparse vegetation. Sand and gravel basins drain to central salt flats from which borax, potash and salt are extracted. Silver, tungsten, gold and iron deposits are in abundance.

The Mojave Desert hosts about 200 endemic plant species found in neither of the adjacent deserts.  Cactus are usually restricted to the coarse soils of bajadas.  Mojave Yucca and, at higher elevations Desert Spanish Bayonet, a narrow-leafed yucca, are prominent.  Creosote Bush, Shadscale, Big Sagebrush, Bladder-sage, bursages and Blackbush are common shrubs of the Mojave Desert.  Occasional Catclaws grow along arroyos, but unlike the Sonoran Desert trees are few, both in numbers and diversity.  The exception is the Joshua-tree.  While this unusual tree-like yucca is usually considered the prime indicator of Mojave Desert vegetation, it occurs only at higher elevations in this desert and only in this desert.

- A.R Royo
Cactus Garden