Fen Management Handbook - Scottish Natural Heritage

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Case Study 6.5
Fen Vegetation Management
– Anglesey Fens
The Anglesey Fens SAC is a complex of six basin and valley-head rich-fen systems
located in the Carboniferous Limestone Region of central Anglesey. The component
sites range in size from a few ha to over 250 ha and support 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, as well as areas of
base-enriched fen meadow referable to the Eu-Molinion (NVC community M24)
and other calcareous types (notably M22). Of particular importance is the quality
and range of M13 seepage communities dominated by black bog-rush (Schoenus
nigricans); other key features include areas of open sedge- and brown-mossrich
vegetation, sometimes with great fen-sedge (Cladium mariscus), and less
base-enriched vegetation dominated by Cladium with purple moor-grass (Molinia
caerulea), blunt-flowered rush (Juncus subnodulosus), bog myrtle (Myrica gale)
and a range of ericoids referable to the non-NVC Cladio-Molinietum.
Cors Goch, Anglesey, the
most intact of the Anglesey
Fens (Pete Jones).
Past management
Little detail is known about the past management of the Anglesey Fens, but it’s
certain that all were utilised much more extensively in the past than has been the
case during the last three decades. All of the larger sites have been heavily cutover
for peat and it is likely that this has resulted in the loss of ombrogenous or
near-ombrogenous surfaces on at least one site and also expanded the influence
of calcareous seepage water across all sites. All sites would have been utilised for
grazing, mainly in the summer, and winter/spring burns were frequent to provide a
seasonal bite of vegetation. Extensive drainage was also undertaken, especially in
the case of the larger sites and was sufficiently intensive to allow some conversion
of habitat to agricultural grassland. After designation as SSSI, three sites were
acquired by conservation bodies (CCW and the North Wales Wildlife Trust) and
designated as NNR. The initial emphasis was on repairing the worst effects of
drainage. Efforts to secure effective grazing proved much less successful away
from the NNRs and management neglect has been a dominant feature of the site
series. Together with the rich-fens of the Lleyn Peninsula, restoration work on the