Over the last century, the Alpine riverscape has undergone profound transformations due to hydropower development, environmental risk mitigation, land-use changes, and riparian vegetation management. These landscape engineering modifications have fragmented the riverscape, disrupting natural biophysical gradients and altering downstream ecological processes. Among anthropogenic disturbances, large water-tight dams represent the most extreme form of disruption, fully interrupting habitat continuity, modifying downstream water and sediment budgets, and resetting longitudinal processes.

The recovery of aquatic communities downstream of such barriers has been widely explored, however open ecological questions remain. Building on the Serial Discontinuity Concept, this study investigates the longitudinal recovery of macrozoobenthos communities in a steep, confined Alpine river in south-western Switzerland, located downstream of the Grand Dixence dam, and explores the ecological role played by tributaries in controlling recovery dynamics. By tracking the recovery trajectory of benthic fauna throughout the year in a heavily human-impacted riverscape, we will include perspectives on the seasonal fluctuations in community structure and the role of additional human sources of disturbance.

This poster will present the first results of the work, produced after the first year of data collection, focusing on the seasonal fluctuations in longitudinal recovery trends. In a rapidly changing Alpine landscape, shaped by both human pressure and climate change, this study will improve our understanding of regulated river systems and provide valuable insights for developing protection and management strategies aimed at mitigating hydropower impacts.