Fen Management Handbook - Scottish Natural Heritage

174
Limitations / less
appropriate sites
Appropriate sites
Effectiveness /
strengths
Action Timing
Rationale for
use
Technique
Wet /soft sites may only
be possible by hand.
Firmer / seasonally drier
sites where machinery
can be used to aid
cost effectiveness – i.e.
floodplain fens, fen
meadows, some valley
and basin fens.
Usually very effective. Also
removes dominant elements
of the vegetation, thus
aiding growth/recovery
of low growing/light
demanding species.
Late summer (July to
September)
Cut vegetation by hand or
machine (flail or swipe mounted
on tractor or tracked specialist
machine). Removal of cut
material strongly recommended
- heap as biomass piles at
edge of site or remove for
composting.
Mowing and litter
removal
Most site types Expensive.
Difficult over large areas
(e.g. > 0.5 ha) due
to volume of resulting
material and possible
wave action effects
reducing recolonisation.
Very effective for removing
acutely enriched soils which
no other technique can
easily address. Also can be
used to achieve re-wetting
by bringing the ground
surface closer to the water
level.
Any-time when
ground conditions
allow, but preferably
avoiding breeding bird
season. Undertake on
rotation to allow some
undisturbed habitat to
remain.
Hand or more usually machine
stripping, the latter ideally with
a 12T or lighter 360 degree
excavator. Excavated material
should be removed off-site or
better still re-used on-site for
making peat dams and bunds
or infilling ditches.
Removes
accumulated pool
of nutrients in
soil/peat. These
are typically
concentrated in
the top 30 cm of
the profile.
Turf removal and
soil stripping
All site types May result in pulse of
nutrients, but this is
generally short-term.
Usually effective, though
not often in isolation on
enriched sites.
Usually August to
March
Ditch blocking (dams) or
complete infill.
Keeping soils
wet prevents
enrichment
through
mineralisation.
Hydrological
management can
also be used to
stop enriched
water reaching the
surface of the fen.
Rewetting/water
management
Routing enriched water through
constructed wetlands.
Rewetting will usually be
undertaken to rewet soils
rather than as a specific
nutrient reduction
measure.
Use of clean water from an
alternative source