“Païolive” is a karstic plateau covering approximately 15,000ha in the Mediterranean southern France. Canyons, an old oak forest established in a mega-lapies, grassy patches and scrubs in open areas named “Gras”, and the endokarst, together constitute an ecological unit that contributes to the touristic attractiveness of the region. A multidisciplinary study attempted to relate the ecological organization and biodiversity of this ecocomplex to its geological and paleoecological history, and to the human activities that took place in the area since the end of
The last glacial period.
During the Neolithic, human populations inhabited the plateau, and agro-pastoral activities probably contributed to the persistence of postglacial grasslands, while Mediterranean oak forests were spreading from southern refugia. From the Roman period to the Middle Ages, human presence receded. During the 18th century, the “Gras” were planted over with vineyards, and during the 19th century partly cleared of millions of tons of stones, which were stacked in low walls enclosing cultivated plots. Consequently, the oak forest was reduced. However, While two plant species provide evidence of the uninterrupted existence of some grassland patches, various species of lichens, mosses and insects are indicators of forest continuity.
An ongoing All Taxa Biodiversity Inventory (Atbi) shows that the ecological diversity of the ecocomplex results in high species richness. More than 4,500 species have been identified at present. Païolive is probably amongst the
richest sites in France and maybe in Europe for bryophytes, and it is one of the richest in southern France for lichens, chiroptera, and for the saproxylic coleoptera indicators of the natural character of French Mediterranean forests.Païolive also appears as a remarkable biogeographical crossroads. Many species are endemic to the Mediterranean biodiversity hotspot, or to a limited region of southern France, but local endemics, mainly endokarstic species, are few.
More than 450 species are protected either at the international level or at the national level, or else are placed on red lists. Many other species have an obvious heritage value, in particular because they are clearly endangered at the regional or local level. Thus, within the Mediterranean biodiversity hotspot, Païolive represents a biodiversity peak of high value. Moreover, it has an important cultural value due to its prehistoric sites, and to the extensive network of drystone walls that can be considered a fossil vernacular landscape.
Païolive is facing important challenges brought by the decline of agriculture and the development of tourism. Conservation issues are discussed, with a focus on the decline of open areas, where a large number of species are endangered. The expansion of oak woods may condemn diverse open habitats, but is at the same time vital for the long-term conservation of the many species that depend on natural forests. Thus, the future of the Païolive ecocomplex needs well-pondered decisions.