Description
The three areas that make up the nature reserve are the Lases marsh (also known as the 'Palù dei Sfondroni'), the Val Fredda with the 'ice holes' and the Palù Redont.
Porphyry quarrying, which has its main production centre in this area of Trentino, has profoundly changed the environmental context. The three strips protected today are small portions safeguarded from transformation.
The Lases marsh consists of what remains of the marshy area that from the southern shore of the lake creeps southwards into the narrow Val dei Sfondroni, furrowed by the lake's outflow. At present it consists only of a long, narrow strip bordered by two 'walls' of porphyry debris dumped from above.
It is a wetland that is particularly valuable in terms of vegetation, fauna, biology and ecology. In the water, near the shore, valuable plant communities composed of submerged and floating plants can be found; the marsh reed thicket (Phragmites australis), which borders the bank, is replaced in the hinterland by a sedge thicket consisting of the spondicola sedge (Carex elata).
This portion of the Biotope is also very rich in fauna, hosting uncommon or rare species such as the crayfish (Austropotamobius pallipes), the green frog (Rana sinkl. esculenta), the grass snake (Natrix natrix) and some water birds, including the great crested grebe (Podiceps cristatus), the coot (Fulica atra), the reed warbler (Acrocephalus palustris) and the water rail (Rallus aquaticus).
The Val Fredda is also a relict of a once far more extensive situation. It is not only valuable and rare, but is a true unicum in our province. It is a small valley that owes its name to the presence in its valley bottom of many 'ice holes' that induce a cold microclimate in it, very similar to that found in high mountains.
The phenomenon is caused by large air circulations within a large mass of (natural!) debris on the sides of the mountain. In this circulation, the air cools and emerges at the base from large and small holes at the bottom of which ice persists throughout the year, inducing a cold climate in the valley, which allows the life of plant species typical of the Alpine belt above 2000 metres.
All this at an altitude of about 800 metres and immersed in the thermophilic forest typical of the area!
The 'precious heart' of the third portion of the biotope is the Palù Redont, a small, round-shaped peat bog that occupies the bottom of a charming hollow located just above the village of Lases. The interest of the peat bog is mainly botanical: here, in fact, the extremely rare plant association of Caricetum lasiocarpae (a sedge given by Carex lasiocarpa) develops, with the presence of an equally rare dwarf willow, Salix rosmarinifolia.