Study area - The Brabant district
The Brabant district (Brab.) is a large, gently undulating plateau, rarely over 200 m elevation, which is mostly covered by loess deposits from the Pleistocene. Except for several forested sites that usually correspond to sandy and less fertile emergences, the area is mostly used for intensive agriculture. The lichen flora is thus very reduced, and much so that the Haine-Sambre-Meuse depression that borders the district on its southern parts is very industrialized and polluted. The strong atlantic traits that are so characteristic of the forest ground flora, especially in the western part, are no longer expressed in the lichen flora, which is now reduced to ubiquitous and toxitolerant species. Several small rock outcrops exist in the valleys but their lichen flora is very poor.