Year of compilation: 2000

Site description
A former tidal estuary in the Rhine/Maas river system, sealed off from the sea in 1970 (see Haringvliet, 024) and no longer subject to marine influence. The site consists of a flood-plain, polders, marshland and swamp-forest, and is intersected by many formerly tidal creeks. The site is adjacent to Hollands Diep (025) in the west; it does not include three drinking-water reservoirs within its boundary. Human activities include reed-harvesting (`Other' land-use, below).

Key biodiversity
An important roost for geese Anser which come from surrounding feeding areas, but counts underestimate actual numbers. The mean total number of waterbirds in January exceeds 20,000.

Pressure/threats to key biodiversity
The main threats are the pollution of bottom sediments by industrial chemicals, and recreation. Clay extraction will result in marsh restoration in the north of the area.

Protected areas
National High International High2,691 ha of IBA covered by Nature Reserve (Brabantse Biesbosch, 2,691 ha). 806 ha of IBA covered by Nature Reserve (Dordtse Biesbosch, 806 ha). 797 ha of IBA covered by Nature Reserve (Sliedrechtse Biesbosch, 797 ha). 7,100 ha of IBA covered by National Park (De Biesbosch, 7,100 ha). 8,850 ha of IBA covered by Special Protection Area (De Biesbosch, 8,850 ha). 1,700 ha of IBA covered by Ramsar Site (De Biesbosch Zuidwaard, 1,700 ha).

Recommended citation
BirdLife International (2022) Important Bird Areas factsheet: Biesbosch. Downloaded from on 29/01/2022.