The environments of the semi-arid West are highly diverse. Mountains, valleys, broad plains, and deep canyons all play a role in creating opportunities for a diversity of riparian ecosystems. Because of the very arid condition of the West, most species found along western rivers could not survive away from the river and the shallow alluvial water table that supports mesic vegetation in a region characterized by semi-arid or xeric plant species. Rivers, and their associated riparian areas, link much of the West. These linear strands offer migration routes and tend to enhance genetic continuity throughout the region. Cottonwoods are an example of this continuity, creating similarities among western riparian areas. Keystone genera such as cottonwood also are found to have common requirements for recruitment and survival across most of the West. Riparian ecosystems in the semi-arid West have been threatened for more than a century. Development of resource extractive industries from timber and mining to agriculture and grazing have greatly altered valley landscapes and water conditions. Most rivers are dammed, causing natural stream flows to be a thing of the past. Many efforts to restore western riparian ecosystems have not been successful; however, knowledge about riparian ecosystem functions has improved, which has led to increased efforts and greater successes.
Citations and enhanced abstracts for journals articles and documents focused on rangeland ecology and management. RSIS is a collaboration between Montana State University, University of Idaho, and University of Wyoming.