The Great Basin Desert is part of the Great Basin between the Sierra Nevadaand the Wasatch Range. The desert is a geographical region that largely overlaps the Great Basin shrub steppe defined by the World Wildlife Fund, and the Central Basin and Range ecoregion defined by the U.S. Environmental Protection Agencyand United States Geological Survey. It is a temperate desert with hot, dry summers and snowy winters. The desert spans large portions of Nevada and Utah, and extends into eastern California. The desert is one of the four biologically defined deserts in North America, in addition to the Mojave, Sonoran, and Chihuahuan Deserts.
Basin and range topographycharacterizes the desert: wide valleys bordered by parallel mountain ranges generally oriented north–south. There are more than 33 peaks within the desert with summits higher than 9,800 feet (3,000 m), but valleys in the region are also high, most with elevations above 3,900 feet (1,200 m). The biological communities of the Great Basin Desert vary according to altitude: from low salty dry lakes, up through rolling sagebrush valleys, to pinyon-juniper forests. The significant variation between valleys and peaks has created a variety of habitat niches which has in turn led to many small, isolated populations of genetically unique plant and animal species throughout the region. According to Grayson, more than 600 species of vertebrates live in the floristic Great Basin, which has a similar areal footprint to the ecoregion. Sixty-three of these species have been identified as species of conservation concern due to contracting natural habitats (for example, Centrocercus urophasianus, Vulpes macrotis, Dipodomys ordii, and Phrynosoma platyrhinos).
The ecology of the desert varies across geography also. The desert's high elevation and location between mountain ranges influences regional climate: the desert formed by the rain shadow of the Sierra Nevada that blocks moisture from the Pacific Ocean, while the Rocky Mountains create a barrier effect that restricts moisture from the Gulf of Mexico. Different locations in the desert have different amounts of precipitation depending on the strength of these rain shadows. The environment is influenced by Pleistocene lakes that dried after the last ice age: Lake Lahontan and Lake Bonneville. Each of these lakes left different amounts of salinity and alkalinity.
