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This work contributes to research on river type-specific reference conditions (“visionary Leitbild”) and is focused on the natural characteristics of alluvial Danube river landscapes. The analyses are based on river morphological reconstructions of the Danube River in the eastern Machland (Upper/Lower Austria, river-km 2094.4-2084.0) since 1715. These reconstructions yield detailed information on the former habitat composition and fluvial processes. This enables conclusions to be drawn about the original fish fauna of the river-floodplain system and the riparian vegetation. Prior to channelization, the river landscape comprised a complex network of river channels, numerous gravel bars and large islands (anabranched river type). The channel system was dominated (>90 %) by the main channel and lotic side arms (eupotamon) that primarily promoted the rheophilic Danube fish fauna. The results support the central hypothesis of the dissertation that – despite the high degree of hydromorphological turnover – a dynamic equilibrium of aggradation and erosion processes largely existed. This state of the riverine ecosystem can be described as a “shifting-mosaic steady-state”, characterized by a gradient of differently developed habitats. The balance of habitat succession and regeneration is reflected by a morphologically very young river landscape with a comparably brief habitat life-time cycle. River channelization and hydropower plant construction since the 19th century increasingly stabilized the river landscape. As a consequence, the former dynamic habitat types have been heavily reduced. The natural cycle of aggradation and erosion became disrupted and the current river landscape is characterized by missing habitat regeneration and prevailing senescence. Altogether, this state no longer constitutes a “shifting-mosaic steady-state system” but rather a “static-state system”.