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.
- Biodiversity of the Terrestrial Cyanobacteria of the Atacama Desert, Chile
- Classical Biological Control of Dalmatian (Linaria dalmatica), Yellow (L. vulgaris) and Hybrid (L. dalmatica x L. vulgaris) Toadflax
- Developing Herbaceous Plant Materials for the Great Basin
- Does Drought Exacerbate Damage Caused by Bark-Beetle-Associated Fungi in Piñon-Juniper Woodland Ecosystems?
- Drought Adaptation of Three Purshia Species: Implications for Propagation, Atificial Regeneration, and Assisted Migration
- Ecological Genetics of Big Sagebrush (Artemisia tridentata): Genetic Structure and Climate Responsive Seed Zone Mapping
- Ecology, Management and Restoration of Great Basin Meadow Ecosystems
- Effect of Endophytic Fungi on Cheatgrass (Bromus tectorum L.) Growth and Fecundity
- Equipment and Strategies to Enhance the Post-wildfire Establishment and Persistence of Great Basin Native Plants
- Exploring the Potential for Cheatgrass Biocontrol with Naturally Occurring Fungal Pathogens
- Great Basin Native Plant Selection and Increase Project
- Greater Sage-Grouse and Energy Development
- Historical and Modern Fire Regimes of the Great Basin and Colorado Plateau: Temporal and Spatial Drivers of Variation
- Management of Prairie Dog Colonies for Grassland Sustainability
- Mountain Big Sagebrush Post-Fire Recovery (Succession) in the Southern Half of its Distribution
- Potential Use of Biochar, a By-Product of Converting Biomass to Bioenergy, as an Amendment to Substrates Used to Grow Native Plants
- Predicting and Mitigating Potential Climate Change Effects on a Regionally Dominant Ecotonal Desert Shrub
- RMRS and RNGR: the Intersection of Science and Technology Transfer
- Sagebrush Steppe Treatment and Evaluation Project (SageSTEP): A Test of State-and Transition Theory [Nevada Woodlands Part]
- Salt-Desert Shrubland Stability as Affected by Livestock Grazing, Invasive Weeds and Climate Variability
- Shrub Encroachment, Wildland Fire, Climate Change, and Carbon Sequestration in Three Southwestern Grassland Ecosystems
- Tools to Assess and Assist Vulnerable Species at Risk from Climate Change
- Understanding Ecological Resistance to Annual Grass Invasion and Resilience to Disturbance