Lake Cerknica is situated on the largest polje (karst field) in Slovenia. A temporary eutrophic lake which is usually totally dry in summer and late winter, but with an area of 2,600 ha when full in spring and autumn. There are huge expanses of reed, sedge and wet grasslands. On the eastern border of the lake, there are remnants of a raised bog. The habitats have been little affected by man. There are a few settlements along the border of the IBA, especially to the north and east, the largest being Cerknica town with 3,000 inhabitants. The lake is historically famous for its underground water system, first described in 1689.
Important numbers of the globally threatened Crex crex breed. Other species of global conservation concern that do not meet IBA criteria: Aythya nyroca (1-5 pairs, the most important breeding site in Slovenia; 10-25 birds on passage), Haliaeetus albicilla (2-5 birds feed in the area but do not breed). A total of 230 bird species have been recorded so far, of which 94 species have bred. Besides its international importance, the site has great value for nationally rare breeding species and nationally important numbers of waterbirds in winter and on passage.
Pressure/threats to key biodiversity
Wind-surfing, boating and angling cause disturbance to birds. To improve conservation of the lake, legal protection should be enforced, hunting on the lake should be completely banned, angling should be allowed only in certain areas, and planned tourism developments should be nature-friendly. Abandonment of extensive farming would lead to loss of wet grasslands and may be a problem in future, thus involvement of (and support for) local people is necessary. DOPPS founded a local group in 1995 to promote conservation in the area, and DOPPS has gathered and publicized information and proposals that justify the inclusion of Lake Cerknica in a proposed Regional Park, with support from SEN (Euronatur). Field surveys are ongoing, including annual nocturnal counting of Crex crex over the whole area.
National None International None
BirdLife International (2020) Important Bird Areas factsheet: Lake Cerknica. Downloaded from
http://www.birdlife.org on 21/10/2020.