Riparian plant species composition alternates between species from standing and flowing water bodies - Results of field studies upstream and downstream of weirs along the German rivers Lahn and Fulda

摘要

Regulation measures like the installation of weirs led to distinct shifts in riparian plant communities and to a decline of typical riparian plant species occurring along the river shoreline, which is naturally poor in woody plants. These regulation measures include also run-of-river impoundments or weirs that cause distinct differences in hydrodynamic conditions in their direct proximity upstream and downstream. In the course of the year, the downstream reaches are exposed to significantly higher water level fluctuations than upstream. Thus, these reaches are assumed to provide also suitable habitat for riparian plant species of habitats being exposed to frequent disturbance by alternating water levels.