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You are here: Grassland, Shrubland and Desert Ecosystems / Research by Ecoregion / Temperate Semi-Deserts & Deserts

Temperate Semi-Deserts & Deserts

Lupine flower
Great Basin restoration species: Lupinus (lupine) flower

The temperate semi-deserts and deserts of the western United States lie in the rain shadow created by the Cascade and Sierra Nevada Ranges on the west and Rocky Mountains to the East. Winters are long and cold even at lower elevations.

Vegetation is dominated by xerophytic shrubs and perennial grasses. Emblematic of this region are the sagebrush steppe and sagebrush desert shrub ecosystems of the Great Basin and the Columbia River Plateau. The salt-desert ecosystem dominated by drought-tolerant sub-shrubs and grasses is second only to sagebrush ecosystems in land area and importance.

The temperate semi-desert and desert region is further divided into two provinces which are distinguished by differences in topography, climate, and vegetation. In the northern province, flat and rolling landscapes are dominated by sagebrush steppe plant communities. Under natural conditions this plant association is expansive on the northern Great Basin and Snake River and Columbia River Plains of Nevada, Idaho, Oregon, and Washington and on the high desert of Wyoming. The second province occupies the valleys and dry plains of the central Great Basin and upper Colorado Plateau in Nevada, Utah and Colorado. Though present in this province, the importance of sagebrush steppe is diminished as it gives way to the drier conditions of the dominant sagebrush desert and salt-desert shrublands. Imbedded within this province are many mountains and high plateaus with somewhat cooler and wetter climates. In these ecotones mountain shrublands intermix with pinyon-juniper woodlands. Treeless meadows and forests of pine, fir, spruce and quaking aspen occupy the highlands and together these comprise their own mountain floristic division.

Key management issues within this region include invasive species, tree encroachment in sagebrush ecosystems, excessive livestock and wildlife grazing, altered fire regimes, climate change and human population growth. The Grassland, Shrubland and Desert Ecosytems Program has numerous projects to better understand the Temperate Semi-desert and Desert region and its ecosystems, the key threats to the stability of these ecosystems and management options.