Sensibilité des milieux et impacts des activités humaines sur le massif du Ventoux

Résumé En

A map depicting the fragility of the environment has been drawn up (see Appendix), which distinguishes two main groups. 1) Areas of natural vegetation with low human influence. These include : a) the mature forests. These are poorly represented (only 5300 ha) due to previous overexploitation ; b) the pre-climax forest stages (mainly coniferous) covering about 1000 ha ; c) “degraded” habitats (scrub and grassland), which are mapped in terms of their value as pasture. Scrub covers about 2800 ha, and grassland about 1200 ha. These natural ecosystems make up about half of the non-cultivated areas. 2) Areas with severe human pressure. This pressure may be due to one of several activities. Extensive reafforestation has been carried out since about 1860 (much of the natural forest having been destroyed by then), so that the new forests now cover the other half of the non-cultivated areas. In addition to native species, the exotics Pinus nigra ssp. austriaca and Cedrus atlantica have been widely planted. The cultivated areas are restricted to the foot of the mountain, although sheep are grazed to much higher altitudes. The type of agriculture is related to the natural vegetation series being exploited, and in most places is tending towards monoculture (mainly of vines, fruit-trees or lavender). Other human pressures include housing, roads, military activities and tourism ; industry is very limited in extent. The Mont Ventoux shows a fairly balanced relationship between man and his environment for several reasons. 1) Forest is by far the dominant vegetation type (covering about 75% of the massif). 2) The areas of non-climax and degraded vegetation are relatively restricted in extent, and have a considerable landscape value and economic importance. 3) The impact of forestry and agriculture is negligible, since these areas harmonise remarkably well with the natural landscape. 4) There has been no excessive development of other human activities, although the increasing number of holiday homes is a potential threat.