A wide network of river arms and gravel islands ...
... this is how the Tyrolean Lech presents itself to the observer. This labyrinth of gravel and gravel banks is the characteristic image of an intact wild river landscape. The gravel banks are not permanent, but ephemeral - gravel islands disappear and emerge, river courses are relocated.

The cause is the annual floods, during which the entire riverbed is inundated. The water masses carry away the gravel banks and deposit the gravel again in another place. Since the Lech repeatedly interrupts the development of vegetation and creates fresh gravel banks, these habitats appear barren. Depending on the water level, the Tyrolean Lech redeposits its gravel islands. Constant change is the only thing that really lasts in this habitat. Despite their proximity to the waters of the Lech, the gravel banks have a warm microclimate characterized by dryness and heat. Water runs off quickly through the large voids in the soil and is hardly stored. In addition, the gravel banks are exposed to full solar radiation.dry-hot environment and the constant rearrangement movement of the gravel banks create an extreme location. Only specialists from the animal and plant world can exist here, which have developed special survival strategies. As pioneers, they conquer this exposed habitat.