Site description (2002 baseline):

Site location and context
The site is a large complex of lakes, forests, and transition and bog mires. The core of the IBA is Osveia Lake which defines much of the hydrology and climate of northern Belarus.

Key biodiversity
A total of 164 breeding bird species have been recorded, including 36 species listed in the National Red Data Book. Osveia Lake is one of the largest breeding and post-breeding grounds in Belarus for numerous huntable waterbird species: Mallard Anas platyrhynchos, Pochard Aythya ferina, and Coot Fulica atra. The Lake and the surrounding areas have a high value for large concentrations of waterbirds during spring and autumn migration.

Non-bird biodiversity: A total of 16 National Red Data Book plant species have been recorded. Some rare plants include hybrids of Black Alder and Grey Alder (Alnus glutinosa and A. incana), tall-stalk forms of Betula pendula var. carelica, a large population of Yellow Pondlily Nuphar pumila, as well as a rare insectivorous plant Waterwheel Aldrovanda vesiculosa.Four mammal species found on the site are listed in the National Red Data Book of Belarus.

Habitat and land use
The surface of the largest Belarusian eutrophic lake Osveia becomes rapidly overgrown with surface vegetation. Most of the IBA is covered by bogs and transition mires, mixed with pinewoods, birch, and black alder forests. A few mineral islands are scattered across the mires. Forest vegetation covers about 30% of the IBA's overall area, shrubs 4%, meadows 6%. There are few fens. Peat extraction, commercial and amateur fishing, limited forestry, commercial and amateur collection of mushrooms and berries, as well as regulated hunting are the main economic uses. Osveia Lake has outstanding sapropel reserves which can exploited and mined.

Pressure/threats to key biodiversity
Human-caused eutrophication of the lake caused by discharge of waste waters and nutrients from agricultural fields and peat extraction sites, municipal facilities, husbandry farms, as well as by atmospheric precipitation.Disturbances in the hydrological regime caused by peat extraction. Declining water levels in the lake results in a poorer water quality, rapid overgrowth of the lake, shrinking fish resources, and less value for waterbirds. Commercial fishing could be reducing fish resources in the lake.

Protected areas
National Conservation Status: A national landscape zakaznik was established in 2000 on the basis of the former hunting zakaznik.International Conservation Status: An IBA was established in 1998 (code BY001, criteria Â2, Â3).Ramsar site (criterion 1, 5, 6).

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Asvieja. Downloaded from on 25/09/2023.