9: Status of biodiversity in the Walloon Region

No indicators providing summarized biodiversity information have been developed yet. The Walloon Region has therefore opted for the regular monitory of an important number of species, in order to cover as many situations as possible. In the Walloon Region like everywhere else, biodiversity strongly decreased during the 20th century : 33% of the 1,661 species studied are considered extinct, endangered or vulnerable. This percentage shows the extent of the problem. However, analysis should not stop at this observation, as there are progressing, recovering or newly settled species. The main changes in biodiversity are mainly due to :

• the considerable evolution of habitats during the last decades, explaining the main trends that were observed: the general decrease in species linked to shrinking habitats (heathland, calcareous grasslands, wetlands, etc.) and the appearance or increase of some species linked to increasing habitats (conifers, urban areas);
• physico-chemical changes in the environment. Observed consequences on biodiversity range from species loss to physiological modifications. This shows a general decrease in the biological potential. The first symptoms linked to global warming are also visible;
• the effect of protection measures such as:
  • legal protection
  • the creation of protected areas and the ecological management of habitats
  • the ban of some toxic substances and the treatment of effluents;
• the introduction of invasive alien species that can become established to the detriment of indigenous species or of habitats.

The very recent evolution (Rio+10 ?) is more difficult to define. Analysis of data obtained for common bird species using the point count survey method shows significant modifications for 1990-1999. Both declining and raising trends are noted, but are difficult to interpret. Due to the complexity of the identification of biological phenomena and their underlying causes, the precautionary principle through the application of strong environmental protection policies is more than never of a current concern.