Rivers have always been used as transport medium for goods, which still applies to large rivers like the Main, the Danube or the Rhine. Thus, regulation measures were necessary to meet the criteria for navigation. River and floodplain ecosystems, formerly defined by their dynamic character, are therefore confronted with enormous changes in ecosystem functioning, being displayed by reduced functionality of ecosystem services and i. a. distinct changes in plant species composition. The European Water Policy thus adopted the Water Framework Directive, aiming at achieving the good ecological status for all European rivers by 2027, whereby the goal of the good ecological potential is intended for highly regulated water bodies like German Federal Waterways. In which way this can be realized for riverbanks along Federal Waterways and how the success of riverbank revitalization measures can be evaluated, is the subject of this work. To this end, vegetation was sampled along riverbanks of the Main, Danube, Lahn and Fulda during the growing seasons 2016, 2017 and 2018. All rivers are intensively affected by impoundments and riverbank embankments consisting of ripraps. Data analysis was carried out by means of multivariate and univariate statistical approaches and revealed homogeneity in riverbank species composition, although these habitats are naturally characterized by a high level of heterogeneity. Species composition mainly consisted of competitive species, which originally occur in habitats in more distance to the river, as these species reveal no adaptations to recurring flooding events. Typical riverbank species were less frequent and grew in dominance along flat riverbank sites (6%) with higher intensity in water level fluctuations. Thus, the lowering of bank steepness is considered to be effective for promoting species with improved adaptations to changing water levels. The second field study conducted for this dissertation revealed that lowering of bank steepness will be most successful in areas, where averagely higher water level fluctuations are existent. This especially applies to downstream reaches of weirs, which are mainly distributed along secondary Federal Waterways and which are not influenced by the next weir downstream, as water level fluctuations will decline gradually with growing proximity to the next weir. By contrast to secondary Federal Waterways, the areas directly influenced by impoundments (one kilometer upstream and downstream of impoundments) reveal a too high regulation intensity, wherefore these areas are recommended to remain unconsidered for riverbank restoration measures. Furthermore, it is also possible to actively manage the restored species composition by bank structure. Concave flat banks without ripraps but with gravel addition in the transition zone between water and land revealed the most typical species composition for riverbanks. By contrast, species composition of banks that were front-fixed by ripraps in the waterway´s channel was also enriched by species from low-flow to stagnant habitats. The results of the first field study for this work revealed that the removal of ripraps can promote a higher lateral connectivity between river and floodplain and a higher level of heterogeneity in riverbank habitats. Thus, unfortified and front-fixed banks can essentially contribute to biotope-cross linking along Federal Waterways. Due to reasons of traffic safety, the removal of ripraps is largely not feasible along primary Federal Waterways, wherefore riverbank restoration measures are limited to local measures. As secondary waterways are mainly used for leisure purposes, riverbank erosion events that are induced by shipping traffic are not expected. Further, water flow velocity is significantly reduced along upstream areas within a distance of one kilometer to the next weir. Compared to primary Federal Waterways, there thus exist more space for riprap removals along secondary Federal Waterways. As the character of plant species diversity measures is rather descriptive and these measures are not applicable to display species´ adaptation to recurring disturbance events, this approach is not recommendable for the evaluation of riverbank restoration measures. Therefore, this evaluation was carried out by means of species traits of the potential natural vegetation of riverbanks, consisting mainly of low competitive and annual species. Restoration measures were considered to be successful when species composition was characterized by more species with the mentioned traits compared to the basis of comparison (banks protected by ripraps, banks along upstream reaches with reduced hydrodynamic compared to downstream reaches). The analysis of species traits further considered species´ habitat origin and led to the conclusion that Bidentetea species were too rare for a sound evaluation of riverbank restoration measures. As species from flooded meadows displayed the intensity of water level fluctuations much better than Bidentetea species and also originate from riverbank transition zones, they attach great importance in this context.
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