Stage 16: Le Puy-en-Velay > Romans-sur-Isère

At the end of the 18 July stage in Romans-sur-Isère, the race crosses the Sables de l’Herbasse and Balmes de l’Isère Natura 2000 site (FR8201675). This site covers about 1,000 ha, but in a very fragmented way.

The site is composed of sandy environments that enjoy plenty of sunshine. They represent a remarkable natural heritage. They are composed of dry grasslands, cornices, rock shelters (cavities) and hills crowned with hardwoods. These natural habitats are fragmented but form a network on a small natural region scale. 


Located at a geo-climatic crossroads between the Alps and the Massif Central, and encountering three climatic influences (continental, Mediterranean and mountainous), this singular site shelters a rich biodiversity. It is largely composed of bats (such as horseshoe bats, mouse-eared bats and the western barbastelle) among which there are 8 species of Community interest out of a total of 24 enumerated species.

It also has numerous invertebrates (the stag beetle, the Portuguese dappled white butterfly), amphibians (newts, including the great crested newts, frogs and toads, etc.) and reptiles (lizards, grass snakes and vipers).

Plant species are not insignificant either (such as the bug orchid and the Onosma arenaria).

For 70 years, the abandonment of agriculture, the sharp decline of wild rabbits and the disappearance of herds of goats and sheep have led to the grasslands becoming overgrown, which then evolve towards a forest. The grasslands are disappearing, and no longer provide competition nor shade for woody species. Invasive species introduced into gardens, such as the ailanthus and the acacia, also settle on these grassland slopes where they compete with the local flora. Maritime pines also colonise them, from the wooded plateaus.

Peri-urban pressure and recreational use are increasing. These natural spaces now occupy increasingly limited areas, and are therefore threatened with extinction.

Site management must therefore be purposeful and reactive. Actions to control exotic plants, as well as clearing and maintenance activities are regularly carried out, sometimes with the help of owners with whom Natura 2000 contracts are established.