A transition mire is an intermediate stage of a fen developing into an active raised bog. While the plants growing between the clods and beds still extract most of the nutrients from groundwater, plants growing on the clods and beds no longer reach the groundwater with their roots and feed mainly on the nutrients from rainwater. Therefore, sedges and other herbaceous plants characteristic of fens grow between the clods, while, in addition to peat mosses, prostrate shrubs with woody stems grow on the clods, as they do in the active raised bogs.
A quaking bog is formed due to the overgrowing of water bodies. A layer of slurry mud or water remains under the floating mat, which is intertwined with the roots and stems of the plants and has partially turned to peat. Fen plants predominantly grow on the floating mat.
Both transition mires and quaking bogs can be found all across Estonia: transition mires are often located on the edges of bogs, while quaking bogs can be found on overgrown water bodies or on the banks of paludifying water bodies.
Includes the habitat type 3113 (minerotrophic quagmire site type) and the habitat type group 312 (mixotrophic fens) according to Paal.