Plant cover data were collected on 16, 1-ha experimental blocks in C3 and Marsh Creek units of Seney National Wildlife Refuge, 2006-2010. Within each unit, we selected 4 pairs of blocks representing sedge-shrub habitat, with one of the pair assigned to spring burning (C3, May 2008) or summer burning (Marsh Creek, 2007 and 2008). This before-after-control-impact design provided for data collection two growing seasons before the burn (2006, 16 blocks; 2007, 15 blocks) and two-three growing seasons (2008, 2009, and 2010; 13 blocks) after burning; the unburned plot of each pair served as the control, and the burned plot of each pair the treatment. This table provides calculated measures of species richness, Shannon Diversity Index (H), and scores for non-metric multidimensional scaling (3 axes), by treatment, site, and year. These metrics were not calculated for the 2 blocks in C3 dropped from data collection after 2007, or for the one Marsh Creek block burned in 2007 (hence just 13 blocks represented here). Raw data from which these metrics were described in Plant_Taxa_Metadata2.xml.