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The disappearance of reservoirs following the removal of dams alters the morphology of the river and its banks. The banks are rapidly colonised by vegetation.

The recolonisation of the river banks is monitored through annual surveys along the new river. The aim is to determine which species of grass, shrubs and trees dominate and will cover the soil made available by the disappearance of the lakes, from the old forest belt to the new watercourse.

25 stations are monitored annually, taking into account:

• Habitat diversity (woodlands, ponds, streams, wetlands, slopes),
• The diversity of terrain along the banks of the Sélune,
• The mosaic of sediment management methods (land-based or underwater traps, undisturbed sediments).

Our monitoring enables us to determine the specific composition and cover of the vegetation along lateral lines perpendicular to the watercourse (transects).

The photo on the right shows one of the 9 quadrats (1m² surface area) in which the plant species were identified and counted at each of the 25 stations monitored.