Lakes circuit

This vast grassy expanse is one of the finest peat bogs in the Mercantour. Peat bogs are rich in information: its depth is more than 8 metres. The succession of layers contains precious clues (grains of pollen, plant debris, etc…). They allow scientists to date things back as far as 9500 years ago. These wetland areas which have little oxygen but plenty of nitrogen are home to flora adapted to the environment, namely bog plants: sphagnum moss, cotton grass with its gracious white cotton toupee as well as Alpine butterwort, one of the carnivorous plant species which can be found in France.

A bare, secretive and fascinating environment: From Pas du Lausson to Col de la Petite Cayolle, these are the high mountains. The décor is rocky and grass is thin on the ground. This is also the stronghold of audacious plants. In order to protect themselves against the hostility of the climate, they are small and perennial, often with large and colourful flowers. This vegetation which, highly adapted to climatic hardships, is fragile and of exceptional value. Plants which can be found here include the spring gentian, moss campion, glacier crowfoot, the stemless gentian, Alpine toadflax…, but also certain endemic species like Berardia subacaulis and Campanula allionii.

The lake incurs the ramifications of its high altitude. The high level of evaporation in the summer sees it shrink, giving it the characteristic shape of a wine glass in autumn. The freezing weather which causes it to “hibernate” for nearly 8 months a year, would appear to prevent life from surviving in it. However, an energy-capturing phytoplankton began developing there, opening the way to life in the mountain lakes.Here, however, life halted at the plankton stage. The rare organic matter is used by an inactive lifeform. Given that the lake is “cleaned” in this fashion , the waters of this oligotrophic lake are clear, despite it being stagnant.

It is a story of long ago, of the great glaciers which, as they slowly but unstoppably moved, shaped the Alps. Their flow hollowed out softer rocks and smoothened the harder ones, ripping any obstacles out of their way. 10000 years ago, the time of the great blanket of ice and snow came to an end and the glacier began shrinking, leaving behind it great hollows and terminal moraines: the glacial lakes found a home there, like Lac de la Petite Cayolle 3000 years ago.

Refuge managed by the commune of Allos Refuge-bar-restaurant Capacity: 40 places Warden: June to September. Shelter room located just above the refuge, open 365 days per year. Tel. 04 92 83 00 24 refuge-du-lac-dallos.com Val d’Allos Tourism Office: 04 92 83 02 81

Created by the glaciers of the quaternary period, Lac d'Allos is the biggest natural lake at this altitude in Europe (62ha). It waters come from the thawing snow as well as from springs, and they reach up to 42m in depth. It burgeons with more life than in the previous lakes: invertebrates, juvenile fish, brown trout and arctic char.Lac d'Allos is an incredibly fragile environment due to the extreme conditions and the low number of plant and animal species. The arctic trout which exist here are, for reasons which remain unknown, affected by dwarfism. Any pollution or modification of the environment would be disastrous. But the presence of the National Park should today ensure that the lake can live in peace.

The beautiful outlet that you see before you is a singular case in hydrogeology: it is unique in the Mercantour and almost so in the Alps! Indeed, this water is escaping from Lac d’Allos which makes it a very rare case of a lake without an overflow and it is even more remarkable when you consider that this is the biggest natural high-altitude lake in Europe whose depth varies from 42 to 49 metres depending on the year. The spring formed is called Chadoulin, an affluent of the left bank of the Verdon.

The grassy plateau of Laus has been a living memory of life for 9000 years. It was created as the glaciers shrank, a lake occupied the site. The fact that it was not very deep, in addition to the floods of sediment and organic matter flowing into it accelerated the process of filling in this lake. The biggest role was played by bryophytes: while their roots decompose, bryophytes keep growing upwards, trapping pollen. Analysing them allows us to retrace the history of existence in the area. Despite gradually drying out for several thousand years, the process is still ongoing today. This environment is still damp and contains plants which are more readily associated with peat bogs. The winding curves of the Serpentine gleam on this plateau.