Functional responses of aquatic and riparian vegetation to hydrogeomorphic restoration of channelized lowland streams and their valleys

1. Streams and riparian zones are highly heterogeneous ecosystems. Their high biodiversity is promoted by variable flow velocities and water depths, strong hydrological gradients and disturbance regimes. However, human interventions like damming and channelization have degraded these ecosystems worldwide. And, although restoration efforts have increased in the past decades, ecological improvement is lagging. 2. We assessed vegetation development in channelized lowland stream valleys in the Netherlands, combining innovative restoration measures to the stream and stream valleys. This ‘stream valley restoration’ entailed construction of narrower and shallower channels to increase flow velocities during base discharges, meandering of the watercourse to increase flow and depth heterogeneity and excavation of banks to create wide v-shaped stream valleys. We evaluated the effects on functional aspects of the developing in-stream and riparian vegetation by comparing restored stream reaches to n...