The Rocheux

Located in the Theux window, the Rocheux vein was exploited for several centuries for its iron, zinc, and lead ores contained in the limestone rocks. Hundreds of thousands of tons were extracted, particularly in the 19th century. The unusable materials were spread over the surrounding land, forming a calamine pile. After the cessation of industrial activities, a very special flora, the "zinc flora," made up of species that can tolerate the presence of heavy metals, reclaimed the site. The plants that only grow on calamine soils are called strict metallophytes. At Rocheux, this flora is represented by calamine violet (Viola calaminaria), calamine pennycress (Thlaspi caerulescens subsp. calaminare), calamine thrift (Armeria maritima subsp. halleri), sandwort (Minuartia verna var. hercynica), calamine campion (Silene vulgaris subsp. vulgaris var. humilis), and calamine fescue (Festuca ovina subsp. guestfalica). Other plants, such as common bent (Agrostis capillaris), brown fescue (Festuca rubra subsp. commutata), round-leaved bellflower (Campanula rotundifolia), and wild sorrel (Rumex acetosa), are referred to as pseudometallophytes because they tolerate contaminated soils without being specifically tied to them. The site also contains a calcicole lawn and a heather moorland within which various calamine species are also present, giving the place its uniqueness. The fauna is very rich, easily explained by the mosaic of habitats, the nature of the soil, and the favorable exposure. The birdlife mainly includes species from hedgerows. At least four amphibians breed in a small pond nestled in a depression. The viviparous lizard (Zootoca vivipara), slow worm (Anguis fragilis), and grass snake (Natrix natrix) are the three reptiles represented in the area. The calamine substrate and the peculiarities of the vegetation cover prove particularly favorable for the development of a highly diverse and remarkable entomological fauna. For example, we can mention the presence of two butterflies whose caterpillars feed on calamine violet: the pearl-bordered fritillary (Issoria lathonia), a legally protected species in the Walloon Region that thrives mainly on calamine sites, and the silver-bordered fritillary (Boloria selene), very localized in the region and significantly more abundant in the Ardennes. One of the smallest butterflies in the world, Enteucha acetosae, whose wingspan does not exceed 3 mm, has also recently been discovered there! Among the various solitary bees populating Rocheux, the rabbit-collete (Colletes cunicularius) is certainly the most noticeable in spring, when its colonies are in full activity.

Public access: Public access prohibited. Guided tours are organized annually by Ardenne et Gaume and the Verviétois Naturalists.
Type: Site of Great Biological Interest (SGIB)

La biodiversité en Wallonie