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The otter, emblematic species of the Ain river

The sentry of pure waters, the otter occupies a place of choice the river's ecosystem: seeking diversified food, hides in the river banks and good quality water, its presence is emblematic of a river in good health.

The river and its pebble banks
The Ain is an active river: its meanders, its islands move around in its bed of pebbles, fashioned by its floods. Its banks are left bare, new pebble banks are formed. And this is how new environments are born, whilst others, abandoned by the river, will gradually be colonised by the forest.

A flow subject to considerable fluctuations, water that is relatively cool and well oxygenated, alternating deep zones and natural sills, the connection with numerous tributaries and dead branches are so many assets that mean a multitude of species of fish are able to thrive in the river.

As for the gravel banks, they provide perfect nesting grounds for certain species of birds..


The "lônes" or dead branches

The river's old beds, supplied with water either by the river itself when it floods, or by the water table, or both, are wet areas that play a predominant role in the life of numerous species: feeding, refuge, reproduction. They are home to a diversified plant life, typical of wet zones.

The lifespan of a "lône" varies from several decades to several centuries. It evolves naturally by filling up, going from an aquatic environment to marsh and finally becoming a terrestrial environment. It is these different stages of its evolution that explain the huge wealth of habitats for fauna and flora.

Whether these "lônes" function correctly and last out their natural lives depends intimately on their relationship with the river and its water table.


The alluvial forest
Forêt alluviale
Today, this is the most common environment around the Lower Ain river: the areas abandoned by the river are rapidly colonised by herbaceous vegetation, bush willows, then poplars, which contribute to enriching the soil by trapping fines. With only a short lifespan, these species gradually make way for a forest of hardwoods: ash, alder and elm take over. The result is a great diversity of species within these forest habitats.

The massive, but relatively recent presence of the alluvial forest is a sign of the effects of the incision of the Ain's bed – less creation of bare areas, lowering of the level of the river's accompanying water table – but also the abandonment of grazing, which allows scrub growth to appear, then gives way to the forest.

Logjams of wood constitute ideal places for fish to hide, the roots of trees hold the banks together and consume the nutrients present in the ground water, the forest reduces runoff during periods of flooding.


The dry grasslands
Pelouse sèche
This is the environment that has receded the most over the last 50 years around the lower Ain river, mainly as a result of the abandonment of grazing, formerly extensive and itinerant.

These are large areas of pebbles agglomerated with sand and earth. They are dry and with good drainage: they form gaps in the forested areas, opening up the view to ramblers, and the atmosphere can sometimes be close to that of the African savannah.

These grasslands are particularly rich in orchids (some fifteen species) and conducive to the nesting of prairie birds.

La loutre

L'Apron

Le flûteau nageant

Petit Gravelot

Castor

Orchidée


Guêpiers d'Europe