õhukese turbakihiga (≥ 30cm) liigniiske tasandik, mis on üleminekuvorm madalsoost rabaks, toitub mineraalaineterikkast pinnaveest ja osalt sademeteveest; iseloomulik on madalsoo liigirikas taimestik ja kõrgematel mätastel raba taimestik, transitional type of mire between fen and bog; is a flat wet terrain with a thin (≥ 30cm) peat (deposit of dead plants) cover getting its water from both rainfall and surface water and having both diverse plant community characteristic to fens and on higher hummocks typical bog assemblage which have adapted to the low-nutrient conditions like Sphagnum moss.