Flow variability maintains the structure and composition of in-channel riparian vegetation

Abstract

1.Naturally variable river flows are considered to be important for structuring riparian vegetation. However, while the importance of floods for the ecology of riparian vegetation is well recognised, much less is known about the importance of small fluctuations in river flows. 2.We investigated the effect of water supply diversion weirs on the riparian vegetation of upland streams. These weirs remove within-channel fluctuations in flow but do not prevent large floods downstream. We surveyed the in-channel and banktop vegetation of five streams, three of which were regulated by weirs and two of which acted as controls. 3.Unexpectedly, we observed greater species richness within the channel do..