The area covers the Ponor Mountain with altitude of 900 to 1,400 m, situated some 50 km north-west of the capital city of Sofia. It is part of the Western Stara Planina (Balkan Mountain Range). About 60% of the territory of the massif is covered by grassland communities a unique mosaic of mountainous pastures, hay meadows with calciphyle and mesophyte grass vegetation, calcareous cliffs and pastoral patches. The grasslands are surrounded by broadleaved forests of Fagus moesiaca above 1,000 m a.s.l., at places mixed with Carpinus betulus (Bondev, 1991), oak forests up to 600 m a.s.l., mixed oak hornbeam forests between 600 and 1,000 m a.s.l., as well as rocky crests and stony karst terrain and, to a lesser extent, agricultural plots. Ponor Mountain is formed by limestone and dolomites and represents one of the biggest and most characteristic Karst areas in Bulgaria. About 60% of the territory of the massif is covered by grassland communities - a unique mosaic of mountainous pastures, hay meadows, calcareous cliffs and pastoral patches.