Fen Management Handbook - Scottish Natural Heritage

variability and how these relate to areas supporting particular features or habitats of
interest. An informed walk-over survey (preferably with hydrologist and ecologist) is
the best starting point.
Make sure you understand how the fen works hydrologically (i.e. how water enters,
moves through and leaves a fen and its chemistry and quality), how it has changed
in the past, or might change in future. Don’t forget man-made structures such as
ditches and work out how they affect the fen. The next step is to consider the ecohydrology,
i.e. how the hydrology interacts with the fen flora and fauna.
Newbald Becksies is a spring-fed fen on the edge of the chalk of the
Yorkshire Wolds. It once supported plants typical of rich fen, such
as butterwort, Grass of Parnassus and mosses such as Scorpidium
cossonii. Investigations are underway to find out whether abstractions
from the chalk aquifer have starved the rich fen of lime-rich water, or
whether it is ‘simply’ that quantities of agricultural fertiliser have entered
the aquifer which has encouraged stronger plants around the springheads.
A more detailed case study of this site is included at the end of
this section (5.1)
5.6 Identify past and future changes
Past changes in presence and population of key species, extent and condition
of habitat, hydrological and nutrient regime should all be identified. Changes in
hydrology or nutrients and how these might have affected fen flora and fauna, or
how they might affect it in future, should be considered. Interest features may be
in very poor condition, or even absent from a site, because of historical changes in
the hydrological regime or other factors. Under these circumstances, other forms
of evidence, including field observations (e.g. landscape situation, presence and
type of peat or recent alluvial sediments), historical maps or aerial photographs,
anecdotal evidence or old photographs can be used to identify the fen’s potential.
Predictions for climate change are for drier, hotter summers and wetter, warmer
winters which would have implications for the sustainability of wetlands, should
be taken into account in setting management objectives. However, unlike rain-fed
bogs, fens are dependent on the behaviour of water after it has run over the soil,
infiltrated it and emerged again as groundwater. The effect on fens of seasonal
changes in precipitation patterns may be even more difficult to predict.
Biglands Bog, Cumbria
This 12 ha mixed valley and basin fen historically supported a small
raised bog, base-rich seepage and floodplain fen. More recently the
flow characteristics of the input stream have changed, depositing much
silt and spreading nutrients into all but the raised bog, which probably
floats. Management must address factors upstream of the fen, such as
changes in agriculture and nutrient-rich discharges. For more about this
site see Case Study 4.1.
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