De Biologische Waarderingskaart: een wetenschappelijk instrument voor het beleid

The Biological Valuation Map (BWK) is a standardized survey and evaluation of the biotic environment. It covers the whole of Flanders, form nature reserves, the wider countryside to green urban areas. For the survey a set of mapping units is used based on vegetation types, habitats and structure of the vegetation. After a brief historical synopsis, we point to the differences between the first and the second version (= the present) of the BWK and explain how to read and interpret the maps. The Biological Valuation Map is primarily used for the overall description of nature, e.g. the geographical distribution and estimation of the area of habitats. The last years it is also used for different tools in nature conservation policy, e.g. implementation of Habitat and Bird Directive, in relation to nature reserves and in management agreements. We emphasize that before going on with a next version of the Biological Valuation Map, a profound revision is needed and more attention has to be paid to the precise definition of legend units and that explicit criteria should be formulated permitting an unambiguous mapping.