Fens are low to moderately fertile wetlands supporting sedge species such as Schoenus and Baumea and also manuka (Leptospermum sp.). They are fed by both groundwater and surface runoff and often occur on gently sloping ground such as the toes of hillsides. They are characterised by having the water table close to the surface which makes fens very wet but with limited water movement. Another charcteristic feature is that the water table of a fen does not fluctuate much throughout the year. Because they occur on slightly sloping ground, fens are more fertile than bogs (although they often share similar features) and they often grade into more fertile swamps. Within fens there is generally a build-up of peat from the breakdown of dead plant matter.
For more information see*:
Fen factsheet - Northland Regional Council
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