Stagno di Oulx Reserve covers a small area between the 1,063 and the
1,249m of altitude, in the Municipality of Oulx, in upper Susa Valley.
The naturalistic interest of Stagno di Oulx area was already evinced in "Flora Segusina" by Giovanni Battista Re in 1805, where it was mentioned as a station rich in rare species; thanks to two works by Gian Paolo Mondino in 1963 and 1974 in which he thoroughly analyzed the floristic aspects of the area, Stagno di Oulx has been inserted into a first list of areas of naturalistic interest for its richness in rare species for Susa Valley and the whole western Alpine Chain. This list was published by Società Botanica Italiana with the title "Censimento dei biotopi di rilevante interesse vegetazionale meritevoli di conservazione" ("Census of biotopes of considerable vegetational interest deserving conservation"). Among the most interesting species, Mondino mentions Epipactis palustris, Molinia coerulea, Schoenus ferrugineus, Salix repens, Allium scodoprasum, Rhamnus frangula.
Stagno di Oulx derives from the filling up of a quarry used to extract the necessary clay for the bricks to build the Frejus Tunnel (1861 - 1871). Afterwards, the basin was used to produce ice; the ice produced by Salbertrand icehouse met the demand of great part of middle and lower Susa Valley. The icehouse was abandoned in the 30s, as well as agricultural practice and grass mowing; the Lake has slowly filled up and has naturally evolved until it became a pond surrounded by large canebrakes consisting of Phragmites australis, peat bogs and hygrophilous meadows dominated by the presence of Carex and Eriophorum. The forest vegetation is characterized by woodland stretches of Scots Pine with mesophile broad-leaf trees; in the undergrowth willows, viburnums, and Prunus padus grow.
The fauna populating Borello Lake reserve is characteristic of the forests of the mountain environment.
The main animals we can find here are:
In 1979 Società Botanica Italiana inserted Borello Lake in
"Censimento dei biotopi di interesse vegetazionale meritevoli di
conservazione in Italia" ("Census of biotopes of considerable
vegetational interest deserving conservation in Italy"). In 1995 Regione Piemonte,
in order to recognize its great naturalistic value, included it in the
list of Sites of Community Importance established by the European Union
Habitat Directive (1992), aiming at protecting those places housing
rare and endangered animal and vegetable species. Moreover, the Province
established a real Special Nature Reserve enabling a more efficient
safeguard of the vulnerable environmental systems characterizing the
peat bog and the lake, providing at the same time ecocompatible
After the establishment of the Reserve, the lake - whose size is similar to the size of 4 football fields - has been colonized by plants and animals typical of the wetlands. Among the stems of the canebrakes surrounding the stretch of water there are now vegetable species that is difficult to find elsewhere in the Alps, like a small orchid with white flowers, the purple moor grass, the sand leek, the brown bog-rush. The surrounding woodland consisting of birches and scots pines has been enriched by glossy buckthorns and creeping willows. The scots pinewood has covered the areas hit by the stream floods, while where the vegetation is thinner, Artostaphylus uva ursi and Hippophae rhamnoides grow with no rival sciaphilus plants - that is plants avoiding the light and preferring shady areas. In other areas, the alder mixes with the scots pine and the shrubby stratum is dominated by formations consisting of Lonicera xilosteum, Crataegus monogyna, Ligustrum vulgare, Viburnum lantana and Rosa rubiginosa. The alder wood dominates in the wettest stations, where there is no drainage and soils have a thin structure; in these areas the shrub stratum is very thick, with species like the almost exclusive Viburnum and Prunus padus. The high humidity and shadow produced by the alder and the thick shrubs of the undergrowth exclude the pine from these stretches of land.
The canebrake, sometimes intruding, exclusively grows in the area around the lake and limits rarer rival species. For this reason, we try to favor it by eliminating the canebrakes. Moreover, the meadow associations in the valley bottom and on the slopes are characterized by species which well adapt to dry conditions, while they become dominating as the meadow cultivations get abandoned.
After a research by Prof. Mondino, Stagno di Oulx was included in 1974 into a first list of areas of naturalistic interest for the richness in rare species for Susa Valley and the whole western Alpine Chain. Among the others: