In the southwestern US, the composition and abundance of riparian plants has changed as a result of flow regime alteration and the invasion of Tamarix. We investigated trends in vegetation dynamics along the Green and Colorado Rivers in Canyonlands National Park (CNP) from 1976 to 2008 through historical aerial photo analyses. We also explored the relationships between understory and overstory species in riparian habitat of CNP. The effects of river regulation on seedling establishment patterns were assessed in slightly regulated, moderately regulated, and extremely regulated river sections in the southwestern US. Tamarix dominated the overstory vegetation in all river sections in CNP but was less dominant along the Colorado (73% vs. [...]
