Streamsides, or riparian zones, are a critical transition region between terrestrial uplands and the flowing stream ecosystems. These are highly dynamic systems, alternating between inundation and drawdowns resulting from fluctuating water levels , and also subject to the shearing forces of flowing waters. Many plants of the streamside zone are uniquely adapted to, and often dependent upon, these environmental conditions. Healthy vegetation growing along the streamside provide numerous benefits, or ecosystem services, both aboveground and below-ground.
plant stems and leaves intercept flowing water and slow it down, which helps reduce flooding downstream and also filters out suspended sediment;
below-ground, plant roots interweave throughout the soil, helping to stabilize the bank and reduce erosion;
plants contribute to organic matter accumulation in the soil which plays a key role in filtering out nitrate and other dissolved contaminants that can be transported in groundwater, leading to contamination of the stream.