Background The Sonian Forest (Forêt des Soignes/Zoniënwoud) is a 4 421-ha forest in Belgium that is primarily within the administrative region of Vlaams Brabant (Flanders), as well as covering parts of south-east Brussels and Brabant Wallon (Wallonia). Roads and railways, however, run through the forest dividing wildlife populations. Monitoring of road kill of the most common species (e.g. roe deer and red foxes) shows that more 50 individuals die every year. Several protected species are found in the area: Daubenton's bat (Myotis daubentonii), Leisler's bat (Nyctalus leisleri), the European pine marten (Martes martes), ground beetle (Carabus coriaceus), palmate newt (Lissotriton helveticus) and Eurasian beaver (Castor fiber). Populations of critically-endangered species can be maintained or improved by using defragmentation techniques to restore their habitats. Objectives The project aims to connect areas of the Sonian Forest with high ecological value by constructing wildlife crossings (such as underpasses, viaducts and culverts) and erecting fences to impede the access of wild animals to roads and rail lines. It also aims to protect forest biodiversity through nature-friendly and adapted forest management (e.g. the restoration of forest edges along the Brussels ring and the creation of open areas) and by redirecting recreation activities to less sensitive areas. The project site covers 2 761 ha. The necessary measures have been or will be included in a new forest management plan. To achieve this objective, a partnership between the agency for nature and forests, the agency for roads and traffic, the Brussels Institute for Environmental Management, the department of environment and energy and the local government of Overijse and Hoeilaart has been formed. Expected results: The project expects to achieve the following results: Restoration and reconnection of relevant habitats by reinstalling ecological corridors to counteract the fragmentation of the Sonian Forest. This will enable movement between isolated patches of vulnerable species; Extension of the populations of typical species of this forest; At least a 90% reduction in road kill; and Involvement of local residents in the conservation of Sonian Forest and its valuable European habitats and species.