Its natural habitat

Former Durance Delta

The Crau is an alluvial plain of 60,000 ha. It is the fossil delta of the Durance, which for five million years carried pebbles from the Alps. 18,000 years ago, the bed of the Durance was deflected by tectonic movements. Its delta dried up to make way for a semi-arid steppe: the coussoul. The Crau coussoul, which covered most of the plain, has seen its surface area diminish over the centuries. Of the original 50,000 ha of coussouls, only 10,000 ha remain today.

The coussoul, a partly protected natural area

Just a stone’s throw from the Camargue, the Crau steppe, also known as the “coussoul de Crau”, is home of an exceptional biodiversity, the richness and composition of which have no equivalent in Europe. Home to a large transhumant sheep farm, the Crau Plain was classified in part as the National Nature Reserve in 2003. This reserve is co-managed by two complementary structures: the Conservatoire d’espaces naturels de Provence-Alpes-Côte d’Azur and the Bouches-du-Rhône Chamber of Agriculture. Thanks to the status of Nature Reserve, 7,500 ha of coussouls (out of a total of 10,000 ha) are now sustainably protected. A project to extend the Reserve is underway as part of the national strategy for biodiversity. In addition, the Crau is also protected by the European Natura 2000 network.

An unique ecosystem

Many of the birds in the Crau are native to the steppes of North Africa or the Iberian Peninsula. In France, only the coussoul offers the same living conditions. The Crau is therefore home to a large proportion of the national population of these species, such as the Lesser Kestrel, the Calandra Lark and the Little Bustard, and sometimes the entire population, such as the Pin-tailed Sandgrouse. Of the 479 known bird species in France, nearly 300 can be observed in the Crau and 150 in the Nature Reserve.

As far as insects are concerned, the community of arthropods (spiders, insects, millipedes, etc.) of the coussoul, dominated by Mediterranean species, is quite original due to its adaptation to local conditions. Among them is the endangered Crau Plain Grasshopper.

The association of plants such as asphodel, thyme or feather grass which constitute the Crau coussoul makes it a unique plant community in the world. Like all Mediterranean dry grasslands, it is protected under the European Habitats Directive (Natura 2000). A more common plant, the Mediterranean false brome is the basic menu of sheep: not very tasty, it nevertheless has the advantage of being a perennial species and therefore available at any time.

Protecting the Crau Plain Grasshopper, the flagship species of the Crau’s steppe grasslands, is synonymous with protecting an entire ecosystem. The management of its habitat represents one of the main axes of the LIFE SOS Crau Grasshopper project.