IBA Justification

The site was identified as important in 2016 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species'):
Species Current IUCN Red List Category Season Year(s) Population estimate at site IBA criteria met
Tundra Swan Cygnus columbianus LC non-breeding 2011-2015 624-1,507 individuals B1i, C2, C6
Barnacle Goose Branta leucopsis LC non-breeding 2011-2015 13,624-23,215 individuals A4i, B1i, C2
Greater White-fronted Goose Anser albifrons LC non-breeding 2011-2015 31,500-38,446 individuals B1i, C3
Smew Mergellus albellus LC non-breeding 2011-2015 446-763 individuals B1i, C2, C6
Tufted Duck Aythya fuligula LC non-breeding 2011-2015 12,324-18,218 individuals B1i, C3
Gadwall Mareca strepera LC non-breeding 2011-2015 15,655 individuals B1i, C3
Eurasian Wigeon Mareca penelope LC non-breeding 2011-2015 26,045-45,519 individuals B1i, C3
Common Teal Anas crecca LC non-breeding 2011-2015 7,928-12,054 individuals B1i, C3
Common Coot Fulica atra LC winter 2011-2015 11,167-14,709 individuals B2
Black-crowned Night-heron Nycticorax nycticorax LC breeding 2011-2015 1 breeding pairs C6
Great White Egret Ardea alba LC non-breeding 2011-2015 453-961 individuals C6
Pied Avocet Recurvirostra avosetta LC breeding 2011-2015 192-408 breeding pairs C6
Black-tailed Godwit Limosa limosa NT non-breeding 2011-2015 2,517-4,196 individuals B1i, C3
Black-headed Gull Larus ridibundus LC non-breeding 2011-2015 81,530 individuals A4i, B1i, C3
Osprey Pandion haliaetus LC non-breeding 2011-2015 9-13 individuals C6
White-tailed Sea-eagle Haliaeetus albicilla LC breeding 2011-2015 1-2 breeding pairs C6
White-tailed Sea-eagle Haliaeetus albicilla LC non-breeding 2011-2015 4-6 individuals C6
Common Kingfisher Alcedo atthis LC breeding 2011-2015 22-33 breeding pairs B2, C6
Peregrine Falcon Falco peregrinus LC breeding 2011-2015 3-4 breeding pairs C6
Sedge Warbler Acrocephalus schoenobaenus LC breeding 2011-2015 1,024-1,313 breeding pairs B3
Savi's Warbler Locustella luscinioides LC breeding 2011-2015 57 breeding pairs B3
Bluethroat Luscinia svecica LC breeding 2011-2015 995-1,165 breeding pairs C6
A4iii Species group - waterbirds n/a non-breeding 2011-2015 113,256-225,739 individuals A4iii, C4

The current IUCN Red List category may differ from that which was valid at the time of IBA criteria assessment (2016).

IBA Conservation

IBA conservation assessment
Year of assessment (most recent) State (condition) Pressure (threat) Response (action)
2018 not assessed low medium
Was the whole site assessed? State assessed by Accuracy of information
no unset medium

Pressure (threats to the trigger species and/or their habitats)
Threat level 1 Threat level 2 Timing Scope Severity Result
Energy production and mining renewable energy happening now small area/few individuals (<10%) no or imperceptible deterioration low
Human intrusions and disturbance recreational activities happening now some of area/population (10-49%) no or imperceptible deterioration low

Response (conservation actions taken for the trigger species and/or their habitats)
Protected-area designation Management planning Other conservation action Result
Whole area of site (>90%) covered by appropriate conservation designation A comprehensive and appropriate management plan exists that aims to maintain or improve the populations of qualifying bird species Some limited conservation initiatives are in place medium
For more information about IBA conservation status, please click here

IBA Protection

Protected area (PA) PA designation PA area (ha) Relationship of PA with IBA Overlap of PA with IBA (ha)
Sliedrechtse Biesbosch Nature Reserve 797 protected area contained by site 797
Hollands Diep Ramsar Site, Wetland of International Importance 4,050 protected area is adjacent to site 0
Dordtse Biesbosch Nature Reserve 806 protected area contained by site 806
De Biesbosch Nationaal Park 8,980 protected area overlaps with site 0
De Biesbosch National Park 7,100 protected area contained by site 7,100
Brabantse Biesbosch Nature Conservation Law 1,500 protected area contained by site 2,691
Biesbosch Site of Community Importance (Habitats Directive) 9,640 is identical to site 9,050
Biesbosch Ramsar Site, Wetland of International Importance 1,700 protected area overlaps with site 1,700
Biesbosch Natuurbeschermingswet 9,640 is identical to site 0
Biesbosch Special Protection Area (Birds Directive) 9,478 is identical to site 8,522


Habitat (IUCN level 1) Habitat detail Extent (% of site)
Forest Alluvial and very wet forest -
Wetlands (inland) Standing freshwater, Rivers and streams, Water fringe vegetation -
Artificial/Terrestrial Highly improved re-seeded landscapes -
For more information about the IUCN Habitat classification, please click here.

Land use

Land-use Extent (% of site)
agriculture -
fisheries/aquaculture -
water management -
hunting -
nature conservation and research -
tourism/recreation -
urban/industrial/transport -
water management -
other -

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Biesbosch. Downloaded from on 04/10/2023.