Presentation of the 1000 étangs
A real jewel
The plateau des 1000 Étangs covers an area of 220 km², from Lure to Faucogney, through Mélisey, Servance and the "Col des Croix".
The area is particular for its numerous ponds of varying sizes, a result of the thawing of the glaciers which covered the Vosges Mountains until the end of the last ice age, 12'000 years ago, reshaping the ground in the process.
This extraordinary landscape earned the region the nickname "Little Finland", for the similitarities with this nordic country.
The plateau des 1000 Étangs is also unique for its specific ecosystem, i.e. the bogs, wetlands sheltering protected species, some endangered.
The bogs are part of the characteristic landscapes of our region ; they are very fragile environments sheltering uncommon fauna and flaura in specific habitats. This wetland is characterised by the progressive accumulation of peat (vegetal organic matter not or very little decomposed).
The ponds, like the others wetlands (bogs and marshes), are mostly nested in troughs formed by glacial erosion.
Over the course of the last two million years of the quaternary era, a thick cover of ice gathered on the plateau. This glacier disappeared around 12'000 years ago.
Medieval monks, shaping the reliefs, used this topography and harvested the peat. They were the first to master the water, creating the ponds.
Ponds of Man
The spontaneous pond vegetation was linked to a cyclical traditionnal management.
Legacy of the Middle Ages, the exploitation alternates every three to six years between water filled and temporarily emptied in summer or winter.
This allowed the pond to be maintained, and to recover its fertility. The ponds dried out in summer were cultivated for millet, barley and buckwheat. But this type of agriculture has almost completely disappeared. Farmers now rarely dry out the ponds.
The ponds were emptied around mid-september. This arduous work required lot of manpower and was a major event.
"On the eve of the big day, the emptying had begun, on the morrow, very little water was left, the fishes packed in it. Men in high boots up to the hip were pushing the fishes toward the spillway, whose gates were opened to clear the remaining water. The fishes were going along, but a net was waiting for them ... Fishermen were catching them by hand or with dip-nets.
In the ponds, waters are shallow, with very little renewal. Fed by rainwater and run-off, they act as solar collector, redistributing a luminous energy necessary for plant growth. The mixing and circulating of temperate water on the surface and colder water on the bottom create a thermic flow favourable to water oxygenation. Wind stimulates evaporation and contributes to maintain these oxygen levels.
The bottom of the ponds is covered in mud, made by the interaction between the original ground and the vegetal and animal deposition. This mud makes the water acidic, which determine its biological production.
Like any ecosystem, the balance of a pond is constantly put at risk by the evolution of exchanges among all its elements.
Quality through plants
We can determine the health and functioning of a pond through its vegetation.
Different categories of vegetals exist in and around the water.
The ponds must be considered as invaluable for many reasons. At the crossroads of contrasted natural habitats, they shelter numerous species in an original setting : glacial relict, mountain species, sometimes continental. The ecosystem of these ponds situated at the top of the watershed plays a preponderant role in the water quality and hydrologic equilibrium.