Legacy sediment removal and floodplain reconnection's effect on plant community dynamics in recently restored Piedmont streams

Abstract

Stream restoration is growing in popularity as a Best Management Practice to address regional Total Maximum Daily Load and stormwater management requirements. Legacy sediment removal and floodplain reconnection (LSR&FR), a new stream restoration technique, involves removal of sediment accumulated behind historic mill dams to address stream downcutting in the mid-Atlantic Piedmont. This method aims to improve on older techniques by restoring overbank flows and associated ecological functions. Comparison of vegetation communities in restored and unrestored reaches showed that restored reaches had significantly higher proportions of hydrophytic and native vegetation. Restored and unrestored reaches also had distinct vegetation communities, but the location within the watershed remained an even stronger determinant of community composition. Most of the responses reported in this study are likely due to a combination of wetter hydrology, decreased forest canopy, and unexpected contributions from the original seedbank. Our finding indicate LSR&FR is not adversely impacting vegetation communities.