| Location | Poland, podlaskie |
| Central coordinates | 22o 50.00' East 53o 30.00' North |
| IBA criteria | C1, C2, C3, C4, C6 |
| Area | 136,900 ha |
| Altitude | 100 - 125m |
| Year of IBA assessment | 2010 |
Ornithological information This is the most important breeding place in central and western Europe for some threatened or localized species such as Gallinago media, Crex crex, Porzana porzana, Aquila clanga and Chlidonias leucopterus, and is also an important site for migrating waders, ducks, geese and Grus grus. Breeding species of global conservation concern that do not meet IBA criteria: Aythya nyroca (1-3 pairs), Haliaeetus albicilla (four pairs), Crex crex (common).
Site description The site comprises the whole of the natural (unregulated) course of the Biebrza river (164 km long) and its valley, along the border of the buffer zone of Biebrza National Park. The valley can be divided into three parts (the upper, middle and lower basin), which differ in physiography, hydrography and ecological character. In the upper basin the river is small and cuts through peat deposits. This area has been partly drained and presently consists of bogs, pastures and meadows, with fragments of marshy pine Pinus forest and mixed forest of oak Quercus and Pinus. The middle basin is dominated by fens, being a mosaic of open and scrub-covered sedge-beds and meadows on alluvial soils. Here there are two extensive areas of natural birch Betula forest and some areas are covered with swampy alder Alnus forest (admixed with spruce Picea) and fragmented Pinus forest. The lower basin floods in spring, so is used for haymaking and non-intensive cattle- and horse-grazing. The lower basin is 30 km long and 5-12 km wide. Valley mires here (mainly fens) are natural and have not been modified by man. Along the river are extensive wet meadows (covering c.10% of the lower basin) and many oxbow lakes covered with reeds Phragmites. Areas which are regularly and extensively flooded each spring are dominated by sedge-beds. Unflooded areas are covered by variably dense forest of willow Salix and Betula, as well as sedge-beds. Scrub succession here is proceeding rapidly. Farther away from the river there are extensive young riverside forests Alnus in marshy areas and fragments of mixed forest Quercus/Pinus.
| Species | Season | Period | Population estimate | Quality of estimate | IBA Criteria | IUCN Category |
|---|---|---|---|---|---|---|
| Black Grouse Tetrao tetrix | breeding | 2008 | 107 males only | good | C6 | Least Concern |
| Greater White-fronted Goose Anser albifrons | passage | 2007-2010 | 50,000 individuals | poor | C3 | Least Concern |
| Tundra Swan Cygnus columbianus | passage | 2007-2010 | 300 individuals | poor | C2 | Least Concern |
| Eurasian Wigeon Anas penelope | passage | 2007-2010 | 25,000 individuals | poor | C3 | Least Concern |
| Northern Pintail Anas acuta | passage | 2007-2010 | 10,000 individuals | poor | C3 | Least Concern |
| Black Stork Ciconia nigra | breeding | 1990-1992 | 24-26 breeding pairs | - | C6 | Least Concern |
| White Stork Ciconia ciconia | breeding | 2009 | 300-400 breeding pairs | unknown | C6 | Least Concern |
| Great Bittern Botaurus stellaris | breeding | 1991-2000 | 27-120 males only | unknown | C2, C6 | Least Concern |
| Great Egret Casmerodius albus | breeding | 2008-2009 | 10 breeding pairs | good | C6 | Least Concern |
| White-tailed Eagle Haliaeetus albicilla | breeding | 2005-2009 | 12-13 breeding pairs | good | C6 | Least Concern |
| Western Marsh-harrier Circus aeruginosus | breeding | 1991-1997 | 170-296 breeding pairs | - | C6 | Least Concern |
| Montagu's Harrier Circus pygargus | breeding | 1997 | 97 breeding pairs | - | C6 | Least Concern |
| Lesser Spotted Eagle Aquila pomarina | breeding | 2005-2009 | 34-35 breeding pairs | good | C6 | Least Concern |
| Greater Spotted Eagle Aquila clanga | breeding | 2005-2009 | 21-23 breeding pairs | good | C1, C6 | Vulnerable |
| Corncrake Crex crex | breeding | 2006 | 700 males only | poor | C1, C6 | Least Concern |
| Little Crake Porzana parva | breeding | 1991-1997 | 27-80 males only | - | C6 | Least Concern |
| Spotted Crake Porzana porzana | breeding | 1991-1997 | 300-1,500 males only | - | C6 | Least Concern |
| Common Crane Grus grus | passage | 2009 | 1,900 individuals | good | C2 | Least Concern |
| Common Crane Grus grus | breeding | 2009 | 600 breeding pairs | medium | C6 | Least Concern |
| Great Snipe Gallinago media | breeding | 1991-1997 | 400-480 males only | - | C1, C2, C6 | Near Threatened |
| Common Snipe Gallinago gallinago | breeding | 2006 | 2,500 breeding pairs | unknown | Least Concern | |
| Black-tailed Godwit Limosa limosa | breeding | 2007-2010 | 200 breeding pairs | poor | C1 | Near Threatened |
| Eurasian Curlew Numenius arquata | breeding | 2007-2010 | 50 breeding pairs | poor | C1 | Near Threatened |
| Ruff Philomachus pugnax | passage | 2007-2010 | 20,000 individuals | poor | C2 | Least Concern |
| Whiskered Tern Chlidonias hybrida | breeding | 1991-2000 | 1-150 breeding pairs | medium | C6 | Least Concern |
| Black Tern Chlidonias niger | breeding | 1991-1997 | 200-700 breeding pairs | - | C2, C6 | Least Concern |
| Eurasian Eagle-owl Bubo bubo | breeding | 2005-2009 | 34-35 breeding pairs | good | C6 | Least Concern |
| Short-eared Owl Asio flammeus | breeding | 2008-2009 | 4 breeding pairs | poor | C6 | Least Concern |
| White-backed Woodpecker Dendrocopos leucotos | breeding | 2005-2009 | 100 breeding pairs | medium | C6 | Least Concern |
| Grey-faced Woodpecker Picus canus | breeding | 1990-1997 | 70-80 breeding pairs | - | C6 | Least Concern |
| Aquatic Warbler Acrocephalus paludicola | breeding | 2009 | 2,528 males only | good | C1, C6 | Vulnerable |
| Bluethroat Luscinia svecica | breeding | 2006 | 100 breeding pairs | poor | C6 | Least Concern |
| Ficedula parva | breeding | 1991-1997 | 250-350 breeding pairs | unknown | C6 | Not Recognised |
| A4iii Species group - waterbirds | passage | 2007-2010 | 100,000 individuals | poor | C4 |
| IUCN habitat | Habitat detail | Extent (% of site) |
|---|---|---|
| Forest | Alluvial and very wet forest; Broadleaved deciduous woodland; Mixed woodland; Native coniferous woodland | 26% |
| Other | 1% | |
| Grassland | Humid grasslands | 27% |
| Wetlands (inland) | Fens, transition mires and springs; Raised bogs; Rivers and streams; Water fringe vegetation | 31% |
| Artificial landscapes (terrestrial) | Highly improved re-seeded landscapes; Other urban and industrial areas; Ruderal land | 15% |
| Land-use | Extent (% of site) |
|---|---|
| agriculture | 26% |
| forestry | 28% |
| not utilised | 43% |
| nature conservation and research | 47% |
| hunting | - |
Management considerations Unsustainable exploitation of birds is high. In the upper basin, local people propose further drainage of bogs, and illegal fires are set by land-owners every year. The middle basin was partly drained in the nineteenth century. Fishermen and tourists cause some disturbance to birds. The part of the IBA outside the National Park comprises the buffer zone to the park. The site is an amalgamation of three sites (the former `PL100'-`PL102') identified in the previous pan-European IBA inventory (Grimmett and Jones 1989).
Protection status National Partial International Partial59,223 ha of IBA covered by National Park (Biebrzañski, 59,223 ha). 59,223 ha of IBA covered by Ramsar Site (Biebrzañski, 59,223 ha).
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Recommended citation BirdLife International (2013) Important Bird Areas factsheet: Biebrza river valley. Downloaded from http://www.birdlife.org on 26/05/2013
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