These data were compiled based on field observations and available literature. Field observations of plant cover were made in September and October of 2013 and 2014, while trait measurements were made in September and October of 2014 and 2015. Field data was collected on sandbars along the Colorado River through Grand Canyon between river miles 0 and 226. Field measurements of specific leaf area, stem specific gravity, and total cover. Plant height was taken from the Flora of North America, the Jepson Desert Manual, or A Utah Flora. Seed mass values were available from the Kew Seed Information Database (http://data.kew.org/sid/). Photosynthetic pathway was compiled from published literature. The trait values were converted to a community-level value using two matrices: a matrix of the relative species cover (species cover/total cover) and a matrix of the average trait value for each species. These two matrices were multiplied, and then summed over all species in each plot to produce a community-level trait value for each plot. Inundation was calculated as the yearly average of the number of hours for each plot that the river stage, based on stage-discharge relationships, was greater than the surveyed plot elevation using USGS streamflow data. This exceedance probability was calculated as the probability that stage height will exceed plot height for the 2013 survey plots based on the 1984 - 2013 USGS streamflow record.