Seasonal and spatial bank habitat use by fish in highly altered rivers – a comparison of four different restoration measures

Abstract

Pander J, Geist J. Seasonal and spatial bank habitat use by fish in highly altered rivers – a comparison of four different restoration measures. Ecology of Freshwater Fish 2010: 19: 127–138. © 2009 John Wiley & Sons A/SAbstract – River regulations have resulted in substantial modifications of the characteristics and the diversity of stream ecosystems. Fish habitat use in the context of species life histories and temporal habitat dynamics are crucial for the development of sustainable measures of habitat restoration in degraded rivers. The objective of this study was to compare the effects of introducing four different in‐stream structures (bank ripp‐rapp, benched bank ripp‐rapp, successively grown riparian wood and artificial dead wood, nine replicates each) on the seasonal fish community distribution in a heavily modified stream ecosystem. Species richness and diversity, fish biomass and density showed strong variation (i) between habitat types, (ii) among replicates of the same habitat type, and (iii) in different seasons. The current low abundance of historical widespread rheophilic and migratory fish species in the study stream suggests that technical bank habitat restoration measures are only of limited use for the restoration of highly specialised target species in conservation such as Barbus barbus and Chondrostoma nasus. However, introduction of particular artificial stream structures (in particular of artificial dead‐wood fascines) was found to concentrate biomass and density of none‐specialised fish species like Squalius cephalus, Alburnus alburnus, Gobio gobio or Rutilus rutilus.