Nature-conservancy evaluation of the birds of Medvedce reservoir (NE Slovenia), and the existing threat factors

Nature-conservancy evaluation of the birds of Medvedce reservoir has been implemented on the basis of ornithological data gathered during the 2002-2009 period and through application of eight different conservation categories. Two of them provide for the legal protection of birds, four apply to breeding birds with unfavourable conservation status, and two to breeding birds with populations of national concern. Threat factors to the birds of this area have also been defined, as well as their relative significance and extent of impact assessed with the aid of two different methods. In the study area, 57 species were confirmed to breed or probably bred there, 34 (or 59.6%) of which were of conservation importance, and 12 (21.1%) of the greatest conservation importance. Three species met the criteria for their inclusion among the IBA qualifying species: Little Bittern Ixobrychus minutus, Ferruginous Duck Aythya nyroca, and Spotted Crake Porzana porzana. For these species, the area has been denoted as IBA SI027 Črete. In the study area, the Ferruginous Duck is the only breeding bird of global conservation concern. In 20 species, the breeding population size exceeds 5% of Slovenian population, while in 6 species at least a half of the entire national population breeds here. Two species, i.e. Purple Heron Ardea purpurea and Marsh Harrier Circus aeruginosus, are known to breed only at Medvedce reservoir. In Slovenia, this area is the most important for the breeding of at least four species: Gadwall Anas strepera, Pochard Aythya ferina, Ferruginous Duck and Tufted Duck A. fuligula. Seven threat factors have been identified, six of which have a negative impact on at least one of the species of the greatest conservation importance. The factors with the greatest negative impact on the birds of Medvedce reservoir are hunting (currently practiced) and fish farming (potential).