Bar charts showing frequency of dominance of each submerged canopy species across the five invasion intensities. There is a visually obvious difference in frequency of canopy types at different invasion levels. Invasion levels 1 and 2 are dominated by P. robbinsii and U. purpurea, while invasion levels 3, 4, and 5 are increasingly dominated by Myriophyllum species, although the native species P. amplifolius and P. robbinsii persist until invasion level 5.