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Mountain environments are increasingly under threat of exotic plant invasion. The resistance of mountain ecosystems to invasions is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme environmental conditions. The importance of any one of these factors is highly debated and, likely, ecosystem dependent. The objectives of this study were to evaluate important factors associated with plant invasions in the Wallowa Mountains and explore to what extent patterns of non-native species distributions and their correlates differ from native species along an elevation gradient. We conducted a complete understory vascular plant survey in summer 2012 along and elevation gradient. As shown by non-metric multidimensional scaling, species composition was strongly related to elevation and disturbance gradients. Despite a high level of disturbance at high elevation sites, non-native species were primarily concentrated at the low elevation sites with moderate to high disturbance levels. Non-parametric multiplicative regression modeling indicated that precipitation and canopy openness were the strongest predictors of non-native species abundance whereas elevation and disturbance were the strongest predictors of non-native species richness. Unlike native species, non-native species composition appeared nested in relation to elevation indicating that non-native species found at high altitudes were a subset of the population at lower altitudes. These data suggest that elevation, disturbance, and precipitation are important correlates of non-native community structure along elevation gradients in the Wallowa Mountains. Additionally, the nested structure of non-natives with respect to elevation supports findings that non-natives occurring at high elevations tend to be generalist species.