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Riparian vegetation is structured by hydrogeomorphic processes operating along a nested hierarchy of scales including the watershed, riparian corridor, and stream reach. Yet most studies have focused on reach-scale channel characteristics with limited consideration of either the watershed geomorphic characteristics or longitudinal position along the stream network. We quantified the influences of watershed and reach-scale characteristics in structuring riparian vegetation in small mountain watersheds within the Great Basin. At the watershed scale, bedrock lithology and basin morphometry combined to influence vegetation extent and composition. Riparian extent� was positively related to intrusive bedrock and drainage density, and negatively related to percentage carbonate bedrock and relative stream power. Disturbance adapted riparian tree and shrub species were prevalent in small, rugged, and high-relief watersheds. In contrast, meadow vegetation was favored in large, low-gradient watersheds with alluvium, carbonate and metasedimentary rock types and large side-valley alluvial fans. Riparian vegetation was also strongly influenced by longitudinal position within the watershed. For example, riparian aspen forest was more prevalent in steep, high-elevation parts of the watershed with high stream gradients, riparian willow and shrub communities in middle elevations where valleys broaden, and river birch communities where canyons narrow and frequent flooding occurs. At the reach scale, vegetation structure was strongly related to channel and bank characteristics such as terrace height, particle size, stream slope and width/depth ratio. Results are generalized to develop process-based management guidelines specific to watersheds with different hydrologic and geomorphic characteristics and, thus, resilience to disturbance. By evaluating the plant community with respect to its geomorphic context, our work identifies riparian systems that have greatest susceptibility to ecological state transitions resulting from stream incision and decreases in water tables. Our restoration guidelines incorporate plant community indicators within the overall hydrogeomorphic context driving vegetation patterns and responses to disturbance.