The wetland is situated on the right orographical side of the river Dora Baltea. It entirely covers the alluvial plain near the two quarry lakes which are no longer exploited for the mining activity and are now part of the natural environment. It represents one of the few remaining environments of the bottom of the valley housing many bird species typical of the wetlands. This is due to the strategic geographical position of the site lying between the central valley of the river Dora Baltea and the valley of the Gran San Bernardo. In spring it is possible to observe species which are not typical of Valle d'Aosta, such as purple herons, marsh harriers, and Savi's warblers and even not typical of Italy, such as spotter sandpipers from North America. The reproduction of 43 species is proved, 8 of which are linked to wetlands (mallards, coots, reed wablers, etc.). Les Iles represents one of the last relicts of the ancient riparian landscape of the bottom of the valley. The periodically flooded strips of land are the priority habitat Alluvial Forest of Alnion glutinoso-incanae. The shores of the lake are rich in a typically marshy vegetation. Aquatic vegetation consists of Groenlandia densa, Potamogeton berchtoldii (not very common in Valle d'Aosta), and Ranunculus trichophyllus.
The aquatic vegetation is poor but presents rare species in Valle d'Aosta, like the Opposite-leaved Pondweed (Groenlandia densa) and the Brasca di Berchtold (Potamogeton berchtoldii). The river and the stream banks house typically marshy plants, Common reeds (Phragmites australis), Common cat tail (Typha latifolia), and the rare Dwarf cat tail (Typha minima) while, when the valley becomes deeper, Carexes and Reeds appear. The hygrophile woods articulate themselves into raws situated at an increasing distance from the Dora Baltea, are consist of shrubs, alders and far from the river there is a mixed hygrophile wood made of Willows and Black poplars.
The protected area houses a particularly rich and interesting avifauna, especially during the spring, when accidental species can be sighted in Valle d'Aosta, like Great White Egrets and Common Scoters. In the last decade more than 40 nesting species have been noticed, many of which are characteristic of the wetlands: Little Bitterns, Mallards, Coots, Little ringed plovers, Reed Warblers, and Reed Buntings.