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Location Poland, wielkopolskie
Central coordinates 16o 44.00' East  51o 59.00' North
IBA criteria C3, C4, C6
Area 2,738 ha
Altitude 100 m
Year of IBA assessment 2010

Ogólnopolskie Towarzystwo Ochrony Ptaków

Site description A storage reservoir (777 ha) on the Samica river, connected by the Wonieœæ channel to the Obra river. The reservoir comprises five former lakes (Drzeczkowskie, Witos³awskie, Wojnowskie, Jezierzyckie, Wonieœæ), connected by a narrow channel (c.13 km long, 200-1,300 m wide), with meadows between them. A dam and sluice divide the upper part of the reservoir, where aquatic vegetation is well-developed, from the lower, where such vegetation is very localized. Adjacent there are fish-ponds, forests, meadows and cultivated fields. The reservoir stores water for agriculture and fire-fighting.

Key Biodiversity The globally threatened Aythya nyroca has not bred here since 1995, but the habitat remains and it is believed there is a good chance that it could breed here again, therefore criterion B2 is still applied. Breeding species of global conservation concern that do not meet IBA criteria: Haliaeetus albicilla (one pair). Other notable breeding species include Anas strepera (22 pairs) and Chlidonias niger (20-60 pairs).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Bean Goose Anser fabalis passage  2004-2008  7,000-8,000 individuals  good  C3  Least Concern 
Ixobrychus minutus breeding  2004-2009  23-34 breeding pairs  good  C6  Not Recognised 
A4iii Species group - waterbirds passage  2004-2008  18,000-22,000 individuals  good  C4   

IBA Monitoring

2010 very high favourable low
Medium - based upon reliable but incomplete / partially representative data

Agricultural expansion and intensification marine and freshwater aquaculture - subsistence/artisinal aquaculture happening now majority/most of area/population (50-90%) very rapid to severe deterioration very high
Human intrusions and disturbance recreational activities likely in short term (within 4 years) majority/most of area/population (50-90%) moderate to rapid deterioration high
Over-exploitation, persecution and control of species direct mortality of trigger species - hunting and trapping likely in short term (within 4 years) majority/most of area/population (50-90%) moderate to rapid deterioration high
Residential and commercial development tourism and recreation areas likely in short term (within 4 years) majority/most of area/population (50-90%) moderate to rapid deterioration high

Wetlands (inland) Standing freshwater  777 777 100 good (> 90%) favourable

Ixobrychus minutus 25 25 breeding pairs 100 favourable

Whole area of site (>90%) covered by appropriate conservation designation  Not assessed  Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
OChK Pojezierze Krzywinsko - Osieckie w woj. Wielkopolskim Protected Landscape Area 51,065 protected area contains site 900  
Zachodnie Pojezierze Krzywinskie - PLH300014 Habitats Directive 5,495 protected area overlaps with site 953  
Zbiornik Woniesc - PLB300005 Birds Directive 2,802 protected area overlaps with site 2,517  


IUCN habitat Habitat detail Extent (% of site)
Forest Alluvial and very wet forest; Broadleaved deciduous woodland; Mixed woodland; Native coniferous woodland  18%
Grassland Mesophile grasslands  24%
Wetlands (inland) Standing freshwater; Water fringe vegetation  21%
Artificial - terrestrial Arable land; Highly improved re-seeded landscapes; Ruderal land  35%
Other   2%

Land use

Land-use Extent (% of site)
agriculture 10%
fisheries/aquaculture 75%
forestry 5%
tourism/recreation 15%
water management 40%
hunting -

Protection status National High International None900 ha of IBA covered by Protected Landscape Area (Krzywiñsko-Osiecki, 71,425 ha).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Woniesc reservoir. Downloaded from on 27/11/2014

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