The ecological character of the Upper Sûre Valley is marked by biotopes of great ecological value that are rarely found elsewhere in the Grand Duchy, such as wet meadows, rushes, riparian forests, thermophilic oak woods, grassy formations on siliceous substrates, etc. and rare animal and plant species.

In order to preserve the unique character of the region, it was decided that the Sûre valley - from the Belgian border to the "Pont Misère" - would henceforth be a national nature reserve.