Fen Management Handbook - Scottish Natural Heritage

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Case Study 8.1
Fen Nutrient Management
– Large-scale turf stripping at Cors Geirch,
Lleyn Peninsula, North West Wales.
Cors Geirch is the largest of the Corsydd Llyn rich-fen SAC and comprises an
extensive valley-head fen system fed by groundwater discharge from adjacent
calcareous sands and gravels. The site supports a range of plant communities
referable to the Annex I types alkaline fen and calcareous fen with Cladium
mariscus and species of the Caricion davallianae. It is surrounded by improved
agricultural grassland, with some agricultural improvement spreading onto the
relatively shallow fen peats. In 1993 landscaping of a nearby refuse tip created
a demand for local top soil and thus an opportunity to strip peat from an enriched
rush-dominated pasture on modified fen peat which had been included in a recent
habitat restoration potential study (Shaw & Wheeler, 1992).
Peat removal at Cors
Geirch in 1993.
(Les Colley)
Over the course of two weeks, contractors removed the top 30 cm of the agriculturally
modified peat profile from an area of 5.5 ha and transported it from the fen basin to
the nearest highway using a specially constructed temporary mat and timber road.
The substantial volume of peat involved (c. 16,500 m3) would at the time have
been very difficult to re-use within the site (for example as part of ditch blocking or
bunding operations) and its use for nearby landscaping provided both the means for
its disposal and the actual funding for the project. Subsequently, a series of nearby
springs and seeps were diverted to flow onto the excavated surface. Vegetation
recovery has been monitored and showed the rapid disappearance of residual ryegrass
Lolium perenne and the development of a series of initially poor-fen communities
with elements of M29 and M9a with Carex lasiocarpa on the wetter soaks, mixed
fen–meadow on the drier peats and acid grassland and heath on the driest mineral
soils. The appearance of Drosera intermedia on exposed peat was unexpected and
may have been unintentionally introduced. Long term management of the scrape has
included control of invading willow and grazing. Jones & Colley (2004) provide a
detailed description of the project.