Author(s): Chantal Mariette Hischier; Nico Batz; Cristina Rachelly; Paul Demuth; Volker Weitbrecht; David Florian Vetsch; Christian Dinkel; Christine Weber

Linked Author(s): Cristina Rachelly, Paul Demuth, Volker Weitbrecht, David Vetsch

Keywords: River management; Floods; Climate change; Macrophytes; Macroinvertebrates; Hydrodynamic numerical modelling

Abstract: Floods are the most frequent disturbances and expected to become more intense due to climate change. To investigate the effect of floods of varying intensity and river morphology on habitat heterogeneity and refugia availability for macrophytes and macroinvertebrates, we compared restored, slightly modified, and heavily modified reaches across ten Swiss rivers. Based on hydraulic field data and hydrodynamic numerical modelling of mean flow (QM)and six flood intensities (HQ1–HQ100), we showed that restored reaches offer higher habitat heterogeneity and refugia availability than modified reaches across most flow intensities. As flow intensity increased, both habitat heterogeneity and refugia availability declined – except in areas along riverbanks. Our results showed a strong positive correlation between habitat heterogeneity and refugia availability, encouraging river management to enhance river resilience by improving structural heterogeneity. Our insights provide guidance for conservation and restoration of habitat heterogeneity and flood refugia in the face of climate change with more intense and frequent floods expected.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.148

Year: 2026