Southwest

The Colorado River and its major tributaries provide a crucial water supply for more than 40 million people in the American Southwest and in California. This water supply is primarily used in irrigated agriculture but also provides essential drinking water to many large metropolitan areas. Hydropower is also produced at many of the large dams on the river. River flows have declined...

Ungulates, or hoofed mammals such as elk, deer, and moose, occupy a diversity of habitats across North America, from Canada’s high arctic to the deserts of Mexico. Ungulates play an important ecological role, helping to regulate processes such as nutrient cycling in forests and grasslands, through their grazing activities. They are also economically and culturally important, providing...

Big sagebrush plant communities are important and widespread in western North America and are crucial for meeting long-term conservation goals for greater sage-grouse and other wildlife of conservation concern. Yet wildfire is increasing in the West, turning biodiverse, shrub-based ecosystems dominated by sagebrush into grasslands containing invasive species such as cheatgrass and less...

The Interior Southwest (Arizona, Nevada, and Utah) is home to a vast and diverse geography consisting of deep canyons, great expanses of desert, mountain ranges, and forests, as well as diverse human communities. The majority of the land in these states is held by state, federal and tribal entities; and environmental changes pose challenges to the management of these public and tribal...

Plants and animals undergo certain recurring life-cycle events, such as springtime flowering or migrations between summer and winter habitats, that are often strongly controlled by changes in environmental conditions, including climate. Because species interact, shifts in one species’ phenology can have cascading effects throughout entire food webs and ecosystems. Recent advances have...

Recent Warming This is an initiative to document and understand the science of recent climate warming in the region and implications for natural resources management. SW CASC researchers from Colorado State University, Scripps Institution of Oceanography at University of California-San Diego, and University of Arizona, and their partners, are identifying the extent to which temperature...

California - one of the nation's most populous states - hosts extensive public lands, crown-jewel national parks, and diverse natural resources. Resource managers in federal, state, tribal, and local agencies face challenges due to environmental changes and extreme events such as severe droughts, heat waves, flood events, massive wildfires, and forest dieback. However, state-of-the-art...

Sagebrush steppe is one of the most widely distributed ecosystems in North America. Found in eleven western states, this important yet fragile ecosystem is dominated by sagebrush, but also contains a diversity of native shrubs, grasses, and flowering plants. It provides critical habitat for wildlife like pronghorn and threatened species such as the greater sage-grouse, and is grazed by...

The Southwest U.S. is experiencing hotter droughts, which are contributing to more frequent, severe wildfires. These droughts also stress vegetation, which can make it more difficult for forests to recover after fire. Forest regeneration in burned areas may be limited because seeds have to travel long distances to recolonize, and when they do arrive, conditions are often unfavorably hot...

The 2017 fire season in California was highly unusual with its late seasonal timing, the areal extent it burned, and its devastation to communities. These fires were associated with extreme winds and were potentially also influenced by unusually dry conditions during several years leading up to the 2017 events. This fire season brought additional attention and emphasized the vital need...