|Central coordinates||5o 27.00' East 52o 45.00' North|
|IBA criteria||A4i, A4iii, B1i, B2, C2, C3, C4, C6|
|Year of IBA assessment||2000|
Ornithological information Numbers are based on aerial counts, which tend to underestimate those species with a scattered occurrence. This is the main moulting area for subadult Cygnus olor in the Netherlands, and the main feeding area for Phalacrocorax carbo from Oostvaardersplassen (066), although the actual numbers are poorly represented by the aerial counts. The number of Chlidonias niger is based on numbers flying to roost at Balgzand (013). Other species which do not fulfil IBA criteria include non-breeding Larus minutus (5,100 in January 1983).
Site description Previously the Zuiderzee, this area is now a vast shallow freshwater lake, having been cut off from the Wadden Sea (001) by the Afsluitdijk (in 1932) and with 45% of its extent having been reclaimed. The original IJsselmeer was then bisected by a dyke in 1975, which separated it from the southern part now called Markermeer (038). This site adjoins three subsites 035, 036 and 037 (the figure for the area of this site excludes these subsites) which are located along the Frisian coast. The lake receives Rhine water through the IJssel river (046 and 047) via Lake Ketelmeer (039). The wetland habitat in the subsites is not included in the percentage cover for this site (to avoid overlap). Extraction of sand and water occurs, and natural-gas extraction is planned. Military training (artillery) occurs at Breezanddijk (Afsluitdijk). The lake has been locally deepened to over 25 m by sand extraction. This site, together with site 038, formed part of a single, larger site (former site NL030) in the previous pan-European IBA inventory (Grimmett and Jones 1989).
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Gadwall Anas strepera||non-breeding||1991||480 individuals||good||B1i, C3||Least Concern|
|Eurasian Wigeon Anas penelope||winter||1991||14,040 individuals||good||B1i, C3||Least Concern|
|Common Pochard Aythya ferina||non-breeding||1991||6,038 individuals||good||B1i, C3||Least Concern|
|Tufted Duck Aythya fuligula||non-breeding||1990||28,842 individuals||good||A4i, B1i, C3||Least Concern|
|Greater Scaup Aythya marila||winter||1991||134,121 individuals||good||A4i, B1i, B2, C3||Least Concern|
|Smew Mergellus albellus||winter||1990||361 individuals||good||B1i, C2, C6||Least Concern|
|Common Merganser Mergus merganser||winter||1991||5,524 individuals||good||A4i, B1i, C3||Least Concern|
|Great Crested Grebe Podiceps cristatus||non-breeding||1990||8,669 individuals||good||B1i, C3||Least Concern|
|Great Cormorant Phalacrocorax carbo||non-breeding||1990||10,438 individuals||good||A4i, B1i, C3||Least Concern|
|Common Coot Fulica atra||non-breeding||1991||15,378 individuals||good||B1i, C3||Least Concern|
|Black Tern Chlidonias niger||passage||1991||90,367 individuals||medium||A4i, B1i, C2, C6||Least Concern|
|A4iii Species group - waterbirds||non-breeding||1990-1991||-||unknown||A4iii, C4|
|A4iii Species group - waterbirds||passage||1991||-||unknown||A4iii, C4|
|A4iii Species group - waterbirds||winter||1990-1991||-||unknown||A4iii, C4|
|Protected area||Designation||Area (ha)||Relationship with IBA||Overlap with IBA (ha)|
|De Ven||Nature Conservation Law||17||protected area contained by site||45|
|De Ven||Nature Reserve||17||protected area contained by site||17|
|Friese IJsselmeerkust - NL1000002||Habitats Directive||2,526||protected area contained by site||2,526|
|Friese IJsselmeerkust I||Natural Monument||4,800||protected area overlaps with site||88|
|Friese IJsselmeerkust II||Natural Monument||120||protected area overlaps with site||12|
|IJsselmeer||Wetlands of International Importance (Ramsar)||108,000||protected area overlaps with site||108,000|
|IJsselmeer - NL9803028||Birds Directive||113,290||is identical to site||109,000|
|Onderdijken||Nature Reserve||100||protected area contained by site||100|
|Stoenckherne||Natural Monument||40||protected area contained by site||40|
|Stoenckherne II||Natural Monument||100||protected area contained by site||100|
|IUCN habitat||Habitat detail||Extent (% of site)|
|Wetlands (inland)||Standing freshwater||95%|
|Land-use||Extent (% of site)|
Management considerations The main problems are over-fishing, water management (level deliberately kept high during summer to supply water for farming), pollution by nutrients from the River Rhine/IJssel and by trace pollutants such as cadmium, mercury and DDT (`Other' threat, above), entanglement in fishing nets (involving thousands of birds), and recreation (leisure boating).
Protection status National Low International Low88 ha of IBA covered by Natural Monument (Friese IJsselmeerkust I, 4,800 ha). 12 ha of IBA covered by Natural Monument (Friese IJsselmeerkust II, 120 ha). 45 ha of IBA covered by Natural Monument (De Ven, 45 ha). 40 ha of IBA covered by Natural Monument (Stoenckherne, 40 ha). 100 ha of IBA covered by Natural Monument (Stoenckherne II, 100 ha). 17 ha of IBA covered by Nature Reserve (De Ven, 17 ha). 100 ha of IBA covered by Nature Reserve (Onderdijken, 100 ha). 240 ha of IBA covered by Special Protection Area (Friese IJsselmeerkust, 5,130 ha).
Contribute Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.
Recommended citation BirdLife International (2013) Important Bird Areas factsheet: Lake IJsselmeer. Downloaded from http://www.birdlife.org on 19/06/2013
To provide new information to update this factsheet or to correct any errors, please email BirdLife