Pic de l'Aigle (Eagle Peak)

The path that leads up to the peak takes a short journey through sparse vegetation, called dry grasslands. This is where a vegetal diversity that is unique to calcareous slabs and rocks can be found. In addition to various orchids, the successive blooming of various small plants is as remarkable as the diversity of shrubs such as the alemanchier, common barberry or Mougeot's whitebeam.

“A large staircase with a handrail and a few steps carved into the rock will lead you to an altitude of 990m. From there unfolds a wide panorama, well described by the observation post. The High-Jura is visible in-depth, with the lines of the successive ridges of its forest and the naked roundness of the Jura mountains. Beyond, the Mont Blanc is also visible near the Givrine pass. Over by the Ain combe, the distant relief of the Mâconnais appear in a bluish blur.”

Marc Forestier (“Que faire dans le Parc naturel régional du Haut-Jura”, What to do in the High-Jura Regional Natural Park, Dakota Edition)

Whilst the Chamois is capable of travelling across a 1,000-meter incline in a quarter of an hour, most hikers are only able to climb 1,000 meters in 3 hours. Even an experienced athlete would need one hour to climb such an incline. If the Chamois is such a good climber it is because it has an enlarged heart that is capable of pumping blood through its body at an alarming rate, twice as fast as a human heart, and because it has hooves with two nails that can separate for better adherence to the rocks. A partition between its “fingers”, covered with fur, prevents it from delving too deep into the snow, in a similar way to our snowshoes.

Meeting this species, like others, is very much a question of luck and a significant amount of patience! But once you glimpse one, do not move and it will allow you to watch it for a good while.

The “lagoon” colours of these lakes is a result of the formation of a “limestone vegetation ledge” around them. The shallow waters near the bank warm faster. Due to a chemical reaction, “hot” water is less capable of dissolving CO2. More abundant phytoplankton “absorb” the CO2 dissolved through photosynthesis. Water acidity is therefore slightly reduced. These two factors, when combined, mean that the calcite “drips” and forms “white mud”, full of chalk.

The belvedere of the 4 lakes provides an overall view over the valley of the lakes, a remnant of the last glaciation: Narlay, Ilay, the Petit Maclu and the Grand Maclu. Do you know the legend of the Lake of Narlay? It is said that it covers the location of a village flooded by water. One Christmas night, a faerie requested asylum for one night from all of its inhabitants, in vain, as only the poorest of them offered her refuge. Angered, the next day, the faerie flooded the entire village, save for her host’s home located on the edge of the lake. The new village of Narlay was rebuilt around the house that was spared, but every year, at Christmas, the cockerel in the drowned village signs for the twelve strikes of midnight. 

Widely present in the marsh area between the Petit Maclu and the Grand Maclu, the asp viper is a poor swimmer and seeks sunny areas to ensure its metabolism can function properly. Like many reptiles, it is fearful and has a talent for detecting vibrations. To avoid bothering this species and being bitten, stamp your feet and be careful not to squash it, it will hide well before you even see it!

The waters of the Petit Maclu and the Grand Maclu feed the lake of Ilay. Each occupies a shallow basin dug out by the glaciers around 20,000 years ago.

The Franche-Comté conservatory for natural areas manages the wetlands on the 4 lakes site in partnership with the owning municipalities and local farmers. This site is fill of species specific to open environments which must be preserved.

Once used by farmers, these zones have gradually been abandoned. This is why managers have made maintaining this type of environment a priority by reinstating extensive grazing.

Highland Cattle cows are able to move around on waterlogged soil and find the food that they need. The amount of cattle and grazing periods are adapted depending on the species and environments in question.

A site sheet dedicated to the wetlands on the 4 lakes site is available online:

http://cen-franchecomte.org/document.php?iddoc=63DyRcgMw7YQ42PG

Centred between the banks of the lake of Ilay is an island: the island of La Motte. Archaeological excavations have revealed that is was home to three successive religious establishments. An initial church was erected around the year 1,000 and seems to have burned down. After being rebuilt, a vestibule was added to it by a monastic congregation that ended up abandoning the place. Of the third establishment, we know only that it was abandoned during the 15th century.  A wooden bridge provided access to the structure from the bank and the marshes that are now present were once orchards and pastures.