Fen Management Handbook - Scottish Natural Heritage

Estimates of the original coverage of fen are based on the extent of deep peat
soils that consist of plant remains, formed under the fen. Surviving peat deposits
show how the type of fen found at a particular location can change over time. Fens
can also yield valuable palaeo-ecological evidence, such as pollen, artefacts such
as tools, weapons and implements, or even human bodies. Some of the best
preserved pre-historic archaeological remains have been recovered from fen sites
such as Flag Fen in Cambridgeshire, Star Carr in Yorkshire and the Sweet Track
at Shapwick Heath in Somerset. Such finds can help reconstruct aspects of the
history of fens, and our ancestors. Further information on archaeology is found in
Section 11.
1.3 Understanding fens
Deciding how best to manage and create fens depends on understanding how
fens work, how fens relate to the wider landscape, and how past management has
influenced fens and the wildlife they support.
Topography, hydrology and geology all play important roles in determining how a fen
develops and is maintained. It is not only the geographical location of a fen which
matters but also the type of rock and the way land is managed elsewhere in the
catchment through which water feeding the fen has passed. The different types
of fen are manifest in terms of the mix of plant species and how these interact with
each other, to provide structural niches in which other wildlife such as dragonflies
and birds can flourish.
Fens can be classified in a variety of ways, including the height and/or type of
dominant plant species, for example short sedge fens and tall reed fens, but the
type and stature of vegetation is intrinsically linked to other environmental factors.
Fens are therefore most commonly defined by their association with particular
landscape features, and according to the source of water which feeds the fen.
Section 3: Understanding Fen Hydrology explains more about fen hydrology and
different types of fen. Section 4: Understanding Fen Nutrients explains about the
different types and sources of nutrient critical to fens and how the nutrient status of
individual fens can be assessed.
9