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Location Poland, podlaskie
Central coordinates 23o 40.00' East  53o 4.00' North
IBA criteria C1, C6
Area 5,168 ha
Altitude 146 - 160m
Year of IBA assessment 2010

Ogólnopolskie Towarzystwo Ochrony Ptaków

Site description The site consists of a large basin covered by a thick layer of peat. The basin drains into the upper course of the Supraœl river, which traverses the northern part of the site. Most of the area has been drained by man, but in many places there are still mires. The central part of the basin is occupied by fens (mainly sedge-beds, occasionally reedbeds Phragmites), while the southern part is raised bog, with marshy forest and a variety of bog mosses. There are two small lakes, Gorbacz and Wiejki. The marshy forest is dominated by birch Betula and pine Pinus, with alder Alnus scrub also common.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Corncrake Crex crex breeding  2009  200-270 males only  medium  C1  Least Concern 
Great Snipe Gallinago media breeding  1989-2002  9-17 males only  C6  Near Threatened 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Gorbacz Nature Reserve 114 unknown 114  
Gorbacz NR (Peatbog Reserve) Nature Reserve 114 protected area contained by site 114  
Ostoja Knyszynska - PLH200006 Habitats Directive 136,084 protected area overlaps with site 4,361  
Park Krajobrazowy Puszczy Knyszyñskiej Landscape Park 73,094 unknown 0  
Puszcza Knyszynska - PLB200003 Birds Directive 139,590 protected area contains site 5,168  


IUCN habitat Habitat detail Extent (% of site)
Forest Alluvial and very wet forest; Broadleaved deciduous woodland; Mixed woodland  15%
Grassland Humid grasslands; Mesophile grasslands  50%
Wetlands (inland) Fens, transition mires and springs; Raised bogs; Rivers and streams; Standing freshwater  30%
Artificial - terrestrial Arable land; Highly improved re-seeded landscapes  5%

Land use

Land-use Extent (% of site)
agriculture 55%
forestry 5%
not utilised 40%
hunting -

Protection status National Low International None114 ha of IBA covered by Nature Reserve (Gorbacz [Peatbog Reserve], 114 ha).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Gródek-Michalowo basin. Downloaded from on 25/10/2014

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