Surviving and growing in dynamic floodplains: Habitat heterogeneity drives communities of young fish in the lower river Rhine

Summary

In recent decades, the importance of healthy fish populations in rivers has been increasingly recognised, and floodplain restoration has become a priority in freshwater conservation programs. This PhD research aimed to better understand how restored floodplains function as nurseries for riverine fishes, with the goal of improving recruitment success and restoring fish populations in the lower river Rhine. This thesis shows that restoring floodplains is effective. Each project type provides nursery habitat for different ecological guilds, individual species, and community features (biodiversity or abundance). To increase rheophilic fish populations and overall fish diversity in modified large rivers, it is proposed that river restoration efforts concentrate on establishing spatially heterogeneous patterns and processes in floodplain restoration projects along the river (as in natural rivers), with a focus on projects that have year-round and long-lasting connectivity with the main channel.