Recent biodiversity assessments have recorded more than 35,000 species of animals, plants, fungi and bacteria in the country. Nearly two thirds of these species are animals. Insects are the most numerous: 4,500 species of beetles, 4,500 species of flies and mosquitoes, 2,400 species of butterflies and moths, and more. Vertebrates are at the bottom of the scale, with only 73 species of mammals and 150 species of fishes. Biodiversity experts believe that there may be more species but these have not yet been recorded.
Biodiversity is under serious threat as a result of human activities. The main reasons for the decline of biodiversity are the destruction and fragmentation of natural habitats, pollution and eutrophication caused by agricultural and industrial practices, excessive water catchments in some areas, climate change and perturbations linked to leisure and tourism.
Belgium has developed a national biodiversity strategy and action plan. Environmental policy, including biodiversity policy is a regional competence in Belgium and therefore the regional governments play a major role in the conservation of species and habitats.
There are nine Members of IUCN in Belgium: The Agency for Nature and Forest (ANB), Brussels Environment, Directorate-General for Agriculture, Natural Resources and the Environment, Institute of Zoology - Department of Science and Environmental Management - University of Liège, Antwerp Zoo, Belgian Science Policy Office (Belspo), the Regional Landscape Kempen and Maasland, the Federal Public Service Health Food Chain Safety and Environment, and WWF Belgium.
In addition, Belgium also hosts four international members of IUCN: Confederation of European Forest Owners, European Bureau for Conservation and Development, European Federation of Associations for Hunting and Conservation (FACE) , and International Association for Falconry and Conservation of Birds of Prey.