Fish and other aquatic life utilise the gravel in a riverbed in a variety of different ways: for example, when searching for food and reproducing. In many Swiss waters, the continued supply of fresh gravel from upstream is restricted. How does such compromised bed-load transport affect fish in terms of their feeding and habitat? And what measures can be taken to restore a river's bed-load regime? These are the questions which we are investigating in the interdisciplinary project "Bed-load and habitat dynamics".