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Wildfire can promote productivity and biodiversity in some locations, but in other locations this same disturbance can cause catastrophic ecosystem shifts. In many regions, including the shrubland-grassland ecotone of northeast Wyoming, the role of wildfire remains unclear. A better understanding of how rangeland ecosystems respond to wildfire will enable better management of these systems for multiple objectives, and can also improve our understanding of ecological sites, which are partially defined as areas that respond similarly to natural disturbances. We asked how wildfire influences plant community composition in northeast Wyoming, and whether wildfire operates differently across different ecological sites. In 2014, we sampled plant community composition at 73 pairs of burned and unburned transects across 30 wildfires that burned from 1937-2012. Transects were paired based on grazing allotment, ecological site, slope, aspect, elevation and topographic wetness index. We used nonmetric multidimensional scaling ordination to investigate variability in plant community composition. Wildfires induced long-term community shifts, and these shifts were consistent across ecological sites. Compared to unburned transects, burned transects had <10% as much shrub cover, 15% more perennial grass cover, and a different group of dominant forbs. Time since fire had surprisingly weak effects on plant community composition. Long-term losses of shrubs from burned sites may be problematic for managers attempting to maintain sagebrush habitat for sage grouse (Centrocercus urophasianus) and other wildlife species. Conversely, increased cover of perennial grasses in burned sites suggests that these areas may provide important forage resources. Plant community composition was not strongly associated with ecological site, but varied continuously along gradients defined by surface soil texture, geographic position, and landscape position. Together with the wildfire response data, these results suggest that ecological sites in this region could reasonably be simplified into two or three categories, with a recognition that gradients exist within these broad classes.