Mont Lachat, land given back to nature

What's that pink building perched on the other side of the valley? It's a former sanatorium, a treatment centre for tuberculosis. Because the mountain air and sunshine were thought to help cure respiratory diseases, the Plateau d'Assy was chosen at the beginning of the 20th century as the site for several of these sanatoria. South-facing, high up, and isolated from residential areas, they enjoyed a worldwide reputation.

This U-shaped valley was carved out over 10,000 years ago by glaciers that extended as far as Lyon! All glaciers move forward by deforming and sliding under their own weight: the front of the glacier melts with the warmer temperatures of the valley, while the back is rejuvenated by the compacting of the snow at higher altitudes. These gigantic currents of ice, which are invisible to the naked eye, have carved out and eroded the valley where the town of Chamonix now stands.

A wind tunnel was built on the Mont Lachat pass in 1937 for the purpose of testing aircraft engines in extreme conditions (wind and cold). After being used for a variety of purposes, the site became an industrial wasteland. In 2015, thanks to a large volume of funding, the site was restored and renaturated. This was an ambitious project, thanks in no small part to the use of low emission transportation of labourers, demolition equipment and waste by the Mont Blanc Tramway.

Once the buildings had been dismantled, the soil left bare as a result of these actions was reseeded with a mixture of local seeds (grasses, flowering plants, etc.): pioneer species that contribute to the formation of a substrate and therefore the growth of other species. All in all, around 5,000 m² have been restored! This renaturation project represents an unprecedented scientific experiment.

Underneath its cuddly exterior, the Marmot is a warrior adapted to the harsh conditions of the mountains. When the summer season arrives, its mission is clear: eat as much as possible to build up fat reserves for the winter. To survive hibernation, it needs to bulk up from 3 kg to 7 kg. No worries though, it's equipped for survival: a burly frame, nimble, claw-like paws for grasping food (plants, earthworms and insects) and sharp teeth for chopping and nibbling.

The Col du Mont Lachat is located on the standard route for the ascent to Mont Blanc, the highest peak in Western Europe. This mountaineering route requires special equipment. Between 15,000 and 20,000 people attempt it every year. This large number of visitors is bound to have an impact on this fragile environment: disturbance of wildlife, trampling, and anti-social behaviour (littering, etc.).

You are entering a Protected Natural Area (Espace Naturel Sensible - ENS). This is an area recognised for its natural heritage (fauna, flora, landscape) but which is threatened or vulnerable by urbanisation or human activities. The Mont Lachat ENS has been the site of ambitious restoration work. It is also part of the Mont-Blanc World Heritage Site, and is part of a broader initiative led by the Conseil Départemental to preserve the region's heritage and promote public awareness.

A majestic bird, very useful for the regulation of rodent populations by consuming them, it has always fascinated humans as much as it has been feared. It has often been chosen as a symbol of power, as shown by the numerous coats of arms, the flags of current or former states (Napoleonic Empire, Germany, etc.).It is also a source of inspiration for artists, of admiration, even of worship in different civilizations.However, it has long been persecuted because it was considered to be "harmful". Nowadays, it is protected, like all raptors in France.

This small daytime bird of prey belongs to the Falconidae family, named for its scythe-shaped wings. Its long, pointed wings enable it to fly quickly and with great agility. The Kestrel can be found anywhere from the seaside to the mountains, as long as its prey (small rodents, amphibians and other insects) is found in abundance.

They are more likely to be found in forests during the winter, and roam alpine meadows in the summer: this is their seasonal altitudinal migration. In the event of an attack, it adopts the same escape strategy as its predators (wolves, lynx, eagles for young goats): it flees at full speed downhill! This requires a lot of energy, which it needs to survive the cold and scarcity of food in winter, or to reproduce. So if you come across one, give it time to move away peacefully.

With a heart twice as big as ours and blood containing three times more red blood cells, the Chamois is a true athlete able to climb within 5 minutes what a trained human would do in an hour! The Alpine Chamois can be recognised by its hook-shaped horns and, most notably, its two dark stripes running from its eyes to its muzzle (the rest of its head is lighter). Be careful not to mistake it for the female Ibex: the latter has an almost uniform coloration, even on the head! As for the male Ibex, its long, ridged horns that curve backwards easily distinguish it from the Chamois.