Laimdota Truus, Mati Ilomets, Raimo Pajula, Kairi Sepp
Proceedings of the 14th International Peat Congress
afforestation, fragmentation, low-intensity-drainage, mire-water, vegetation-change
Theme I. Inventory, stratigraphy and conservation of mires and peatlands
In Estonia, agricultural management and afforestation lead to disappearance of extensive areas of fen ecosystems. Some 10 – 20% of fens area remained, either too small or too far for be profitable to drain. Great part of them are subject to weak but long-lasting influence of drainage that lead to vegetation change, especially through afforestation.
We studied plant cover and mire water and upper peat properties on some 60 open fen sites still possessing the near-natural state over Estonia. In the five main plant assamblages distiguished the peat water pH was about 6 – 7, electrical conductivity varied between 80 to 700 μS cm-1, and Ca content from 10 to 260 mg l-1. We concluded that (1) fens that have been remained open are quite similar in their plant cover and water conditions; (2) because of fragmentation and undirect drainage impact many sites are impoverished in their species composition and are increasingly