Background The Alde Feanen is a Natura 2000 site and a national park located in the northern part of the Netherlands. This 2140 ha area is one of the most extensive fenland areas in the Netherlands (and Western Europe). ‘Booming business’, the title of this project, refers to the booming sound of the Bittern (Botaurus stellaris), which occurs in a number of vulnerable wetlands in the area. It also refers to the excellent opportunities for sustainable conservation actions to restore the wetland’s key processes, thus protecting and regenerating the large biodiversity of the Alde Feanen. This biodiversity is currently threatened by the: Strong decline in water reed beds, caused by the disappearance of water level dynamics; Strong decline in submerged water plants, due to high levels of phosphates; Decline of floating fens, caused by ongoing ageing and scrub encroachment; and Decline of fen meadows, caused by ongoing acidification. Objectives The project’s main objective is to improve the functionality and long-term nature prospects for Alde Feanen. Specifically, the project aims to: Restore a large area of water reed beds: in parts of the area, water level dynamics will be restored, albeit not to a natural water dynamics, due to the many conflicting interests. However, there is a unique opportunity to restore water reed beds on a considerable scale, by the flooding of polders, combined with the protection of pond banks; Restore a large area of submerged water plants: growing conditions for submerged water plants in small isolated peat ponds can be greatly improved by a combination of dredging of phosphate rich sediment, the removal of fish stocks that feed on the organisms living in the pond bed (which causes extra turbidity and as a consequence the release of phosphates), flushing the ponds with less phosphate rich water in summer, and local reintroduction of disappeared water plant species; Restore and regenerate floating fens: transition mires and reed lands with encroachment of scrubs and/or tall herbaceous species will be rejuvenated by topsoil removal, and by improvement of the local hydrology; Preserve an important area of fen meadows: in the western part of the Alde Feanen, a large area of Molinia fen meadows is flooded annually. To facilitate this, an existing but currently poorly functioning filter (which filters out excess nutrients) will be restored and extended, and will be used to reduce nutrient loading of the water used for flooding. The project will give a strong ‘boost’ to the Alde Feanen’s water system, and several Natura 2000 habitat types and species will benefit, including the priority habitat type Bog woodland (H91D0) and the priority species Root Vole (H1340). At the same time, the actions proposed will increase the recreational value of the area. Expected results: The project measures will result in the following outcomes. Water reed beds: Restoring a sustainable water reed surface of 55 ha. This will improve water quality and create breeding, foraging and living habitats for many of the Natura 2000 species; Water plants: Strong, long-term expansion of submerged water vegetation (especially H3150 with Water Soldier and pondweeds). Measures will be taken in 80 ha of isolated peat ponds, including the removal of 72 000 m3 phosphate rich sediment, fish stock management on 70 ha, nutrient removal by summer flushing on 38 ha, and small scale reintroduction of aquatic plants, supported by the removal of 125 000 m3 of phosphate rich sediment from the non-isolated parts of the area; Floating fens: Topsoil removal from 25 ha of transition mires and reed lands that have become overgrown, combined with hydrological improvements, will lead to the formation of new habitat type 7140 Transition mires and quaking bogs. This measure is expected to be effective for at least 25 years; Fen meadows: Restoration and extension of an existing filter will allow for the supply of good quality water for flooding. This will facilitate the long-term survival of 30 ha flooded fen meadows (H6410); The perceived spatial quality of the area will increase, and, as a consequence, its socio-economic value. The relevant authorities will include all necessary further conservation actions in their management plans for the area after the project.