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The site was identified as important in 2010 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species') at the site:

Species	Red List1	Season	Year(s)	Size	IBA criteria
Bean Goose Anser fabalis	LC	passage	2004-2008	7,000-8,000 individuals	C3
Common Little Bittern Ixobrychus minutus	LC	breeding	2004-2009	23-34 breeding pairs	C6
A4iii Species group - waterbirds	n/a	passage	2004-2008	18,000-22,000 individuals	C4

1. The current IUCN Red List category. The category at the time of the IBA criteria assessment (2010) may differ.

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2010. The most recent assessment (2010) is shown below.

State (condition of the trigger species' populations)
Species	Reference	Actual	Units	% remaining	Result
Ixobrychus minutus	25	25	breeding pairs	100	favourable

State (condition of the trigger species' habitats)
Habitat	Quantity (% remaining)	Quality (% carrying capacity)	Result
Wetlands (inland)	-	good (> 90%)	favourable

Pressure (threats to the trigger species and/or their habitats)
Threat	Timing	Scope	Severity	Result
Natural system modifications	happening now	majority/most of area/population (50-90%)	very rapid to severe deterioration	very high
Agricultural expansion and intensification	happening now	majority/most of area/population (50-90%)	very rapid to severe deterioration	very high
Residential and commercial development	likely in short term (within 4 years)	majority/most of area/population (50-90%)	moderate to rapid deterioration	high
Biological resource use	likely in short term (within 4 years)	majority/most of area/population (50-90%)	moderate to rapid deterioration	high
Human intrusions and disturbance	likely in short term (within 4 years)	majority/most of area/population (50-90%)	moderate to rapid deterioration	high

Response (conservation actions taken for the trigger species and/or their habitats)
Protected areas	Management plan	Other action	Result
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

Year	Protected Area	Designation	% overlap with IBA
1974	Ostoja żółwia błotnego	Rezerwat Przyrody	<1
1989	OChK Pojezierze Krzywinsko - Osieckie w woj. Wielkopolskim	Protected Landscape Area	100
1992	Krzywińsko-Osiecki wraz z zadrzewieniami generała Dezyderego Chłapowskiego i kompleksem leśnym Osieczna-Góra	Obszar Chronionego Krajobrazu	100
2001	Zachodnie Pojezierze Krzywińskie	Site of Community Importance (Habitats Directive)	35
2004	Zbiornik Wonieść	Special Protection Area (Birds Directive)	92

Habitat1	Habitat detail	% of IBA
Artificial/Terrestrial	Highly improved re-seeded landscapes, Arable land, Ruderal land	35
Grassland	Mesophile grasslands	24
Wetlands (inland)	Standing freshwater, Water fringe vegetation	21
Forest	Broadleaved deciduous woodland, Native coniferous woodland, Mixed woodland, Alluvial and very wet forest	18
Other		2

1. IUCN Habitat classification.

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

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Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Woniesc reservoir (Poland). Downloaded from https://datazone.birdlife.org/site/factsheet/woniesc-reservoir-iba-poland on 22/11/2024.