Division Natural factors

The geographical area comprises the arc of the Jura mountains, a set of limestone plateaux, and its extension into a small part of the adjoining plain. The altitude is often high. The landscape is divided between grassland and woodland. The grassland’s natural limestone flora is very varied.

The whole of the area is characterised by a continental type of climate, with large differences in temperature between winter and summer, and precipitation which, although spread throughout the year, is considerable in summer. The whole of the area is also defined by a northern climate with a low annual average temperature (despite considerable heat in the summer) and a large number of days of frost. It is a very wet mountain or submountain environment with annual rainfall always in excess of 900 mm and generally in excess of 1 000 mm. This rainfall is already considerable at low altitude and increases towards the interior of the mountain ranges. Seasonal distribution is characterised by the lack of a dry season. This climate particularly favours the growth of grass.