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Location Netherlands, Zeeland,Zuid-Holland
Central coordinates 4o 0.00' East  51o 45.00' North
IBA criteria A4i, A4iii, B1i, B2, B3, C2, C3, C4, C6
Area 13,900 ha
Year of IBA assessment 2000

Vogelbescherming Nederland

Site description A former estuary, 18 km in length, which was closed from the sea in 1971. It is now a stagnant saline lake, mostly bordered by dykes with islets, sand-dunes and wet meadows. It adjoins the Voordelta (020) to the west, and Lake Volkerak (026) and Oosterschelde (028) to the east. Hunting does not include waterbirds.

Key Biodiversity This clear, saline lake is especially attractive to piscivorous waterbirds, and the grassland bordering the northern shores (Slikken van Flakkee) is one of the main feeding sites of Branta leucopsis in south-west Netherlands. The site holds important roosts of geese. The mean total number of waterbirds in January exceeds 20,000.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Northern Pintail Anas acuta non-breeding  1987-1991  1,635 individuals  good  B1i, C3  Least Concern 
Barnacle Goose Branta leucopsis winter  1988-1991  11,053 individuals  good  A4i, B1i, B2, C2, C6  Least Concern 
Brent Goose Branta bernicla non-breeding  1988-1991  3,752 individuals  good  A4i, B1i, C3  Least Concern 
Tundra Swan Cygnus columbianus winter  1988-1991  222 individuals  good  A4i, B1i, B2, C2  Least Concern 
Common Goldeneye Bucephala clangula winter  1988-1991  4,823 individuals  good  A4i, B1i, C3  Least Concern 
Red-breasted Merganser Mergus serrator winter  1987-1990  3,883 individuals  good  A4i, B1i, C3  Least Concern 
Eurasian Spoonbill Platalea leucorodia non-breeding  1989-1993  34 individuals  good  B1i, C2  Least Concern 
Great Cormorant Phalacrocorax carbo non-breeding  1987-1990  3,013 individuals  good  B1i, C3  Least Concern 
Pied Avocet Recurvirostra avosetta breeding  1987-1991  420 breeding pairs  good  A4i, B1i, B3, C2, C6  Least Concern 
Charadrius alexandrinus breeding  1987-1991  103 breeding pairs  good  B2  Not Recognised 
Sandwich Tern Thalasseus sandvicensis breeding  1987-1991  2,850 breeding pairs  good  A4i, B1i, B2, C2, C6  Least Concern 
A4iii Species group - waterbirds winter  1991  20,000 individuals  unknown  A4iii, C4   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Grevelingen Wetlands of International Importance (Ramsar) 13,900 protected area overlaps with site 13,900  


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Standing brackish and salt water  80%
Artificial - terrestrial Highly improved re-seeded landscapes  20%

Land use

Land-use Extent (% of site)
fisheries/aquaculture 80%
water management 100%
hunting 20%
nature conservation and research 100%
tourism/recreation 90%
agriculture 5%

Protection status National None International None

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Grevelingen. Downloaded from on 26/10/2016

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