Dominant Merlet, bounded by the aiguillette des Houches, the aiguillette Brévent and the torrent of Diosaz, this small nature reserve is akin to a water garden, with its multitude of streams, lakes, marshes, peat bogs and “dwarf” (local name designating small bodies of water). The passage of the glaciers dug a set of depressions on this plateau.

Humidity and altitude determine the establishment of a rare specific flora. Peat bogs and bas-marshes welcome the larvae of the Cordulie des Alpes, a dragonfly that is fond of the high-altitude peatlands where the sundew, the narrow-leaved ribbon or the Magellan sedge grow, a rare plant found in France only in Savoie and Haute-Savoie. It is also the territory of the red frog and the alpine newt.
The area of ​​the Vogealle, mosaic of lawns and blueberry and rhododendron is frequented by the black grouse.

In the extension of the Aiguilles Rouges Nature Reserve, the wild beech fir forest area overlooking the Diosaz gorges is home to rare and endangered species such as the European lynx, the hazel grouse and the golden eagle. the tridactyl peak.