Cuilcagh and Marlbank Biodiversity Profile
Key Characteristics
- contains some of the most important native woodlands in Northern Ireland, particularly types of hazel scrub/woodland and upland ashwoods
- unusually for Northern Ireland, this LCA has little improved grassland, a product of its upland character
- because of the changing geology and topography, there is a diversity of semi-natural and unimproved grassland types, including upland calcareous grassland, limestone pavements and acid, heathy grassland on sandstone areas
- one of the most extensive areas of upland blanket bog in Northern Ireland, with intact bog and complexes of pools and hummocks; important breeding sites for wetland birds including golden plover
- rare plants in summit and rocky areas - rare habitats in Northern Ireland
Woodlands
This LCA contains some of the most important native woodlands in Northern Ireland, particularly types of hazel scrub/woodland and upland ashwoods. The native woodlands of the Marlbank upland are confined to the scarp slopes and the steeply sided gorges, many of which are in this LCA. In general, these woods are examples of wet ashwoods, although the wetness varies through the woods. Ash is dominant or co-dominant throughout, although locally planted beech, oak, wych elm and conifers replace it. Beech is regenerating successfully, but few oak saplings are present under the planted stands. There is no evidence of conifer regeneration as ash is establishing in clearings created by fallen conifers. Sycamore, although scarce at present is spreading successfully in several woods and if left unchecked, could become a major component of the canopy.
The woodlands show a diversity relative to location on slopes, thus on the scarp limestone cliffs there is only sparse vegetation but with occasional yew and juniper. On the scree slopes below, mature ash dominates with birch, holly and hawthorn although there are parts where hazel forms the dominant canopy cover. The best examples of these mature ashwoods are at Marble Arch and Hanging Rock (Hanging Rock and Rossaa Forest NNR, Marble Arch NNR) although parts were planted in the middle of the nineteenth century and other parts are even-aged following felling during the Second World War. These damp scree slopes have a well-developed herb layer that includes pignut, bluebell, meadowsweet, bugle and angelica. Locally, wood rush is abundant with herb robert, primrose and wood sorrel. At the foot of the scree slopes most of the former woodland has been cleared, but there are patches of ash-alder scrub and woodland with grasses (including false oat-grass, cocksfoot, tufted hair grass) and woodland species (wood sorrel, twayblade, primrose, wood violet).
The woodlands are further diversified by the presence of flushes, where yellow flag iris, soft rush and hard rush dominate with meadowsweet and great horsetail. Throughout, the woodlands are rich in mosses and lichens.
Glen Wood FNR appears to be unusual in the LCA because it is dominated by oak. However, this upland oakwood probably derives from planting in the eighteenth century. While not of natural origin it has been in existence sufficiently long to establish an associated ground flora similar to that which a natural oakwood would have on this type of site. The Forest at Florence Court also contains other areas of oak, mostly of modern planted origin.
Most of the demesne of Florence Court (National Trust) is now under mixed forest with only limited parkland remaining around the house (lowland woodland pasture and parkland). Narrow fringes of semi-natural ancient woodlands survive around the margins and form part of the more extensive areas of rich woodland lying outside the property. The most interesting areas of woodland on the Trust land are the small area of semi-natural, probably ancient woodland, in the south-western corner and the southern edge of Bogavenue Wood, which also has a relatively semi-natural composition. These areas support a moderately diverse woodland ground flora, which includes broad-leaved helleborine. Of particular note are records for bird's-nest orchid, an uncommon species in Ireland. The rest of the woodland on the Trust land is mixed broadleaved woodland with a greater proportion of non-native trees, although there are also a good number of large oak and ash.
Florence Court Forest is dominated by Sitka spruce with compartments of Norway spruce and other conifers; however, broadleaved compartments are common, especially of oak but also including some of beech, of alder, of mixed hardwoods and some scrub. The forest at Doohatty Glebe is almost entirely of Sitka and Norway spruce.
Grassland and Arable
Unusually for Northern Ireland, this LCA has little improved grassland, a product of its upland character. However, because of the changing geology and topography, there is a diversity of semi-natural and unimproved grassland types. Above the limestone cliffs and where the grass is not grazed, the rank grassland is characterized by sweet vernal grass, cocksfoot, lady's bedstraw, yarrow and black knapweed, and where the limestone outcrops blue moor-grass, thyme and harebell also occur. Kilnameel ASSI is particularly important because of the extent of species-rich dry grassland present on the site. Species-rich dry grassland is a particularly rare resource in Northern Ireland and is usually not found in large field parcels. Several field units are managed for hay and are dominated by grasses, notably yellow oat-grass and downy oat-grass. Associated herbs typical of unimproved grasslands, such as common knapweed, ox-eye daisy and eyebright are also present. Some of the banks within the site, where the limestone is very locally exposed, are exceptionally species-rich. These swards are characterised by numerous orchids e.g. twayblade and the notable frog orchid. Lady's bedstraw and yellow-rattle are common with the notable adder's-tongue and mountain everlasting (upland calcareous grasslands).
Killykeeghan and Crossmurrin NNR also shows a rich variety of herbs and grasses on the thin limestone soils. Sheep grazing allows herbs like thyme, harebell and bird's-foot trefoil to flower and set seed. These herbs in turn provide food for insects such as the common blue and peacock butterflies.
The limestone uplands also have areas of limestone pavement. The grikes (weathered joints) provide a niche for a varied assemblage of ferns and higher plants whilst the clint surfaces (the limestone blocks or pavement) support typical calcareous grassland. However, there are several parts where organic soils overlie the limestone pavement and here the grasslands are not calcareous, indeed they contain species of more acid heathland and grassland.
The southern two-thirds of the LCA, culminating in Cuilcagh Mt. is predominantly of sandstones and shales in a sequence of steep slopes and more gently sloping shelves. On the latter, deeper blanket bog is extensive, whereas on the steeper slopes the blanket bog is thinner and merges into acid and heathy grasslands.
Heaths and Bogs
Blanket bog is confined in Europe to the northwest margins of the continent, so that Northern Ireland contains not only a large proportion of the UK's and of Ireland's total area of blanket bog, but also is of major importance at a European scale. Blanket bog, and particularly intact blanket bog, in any LCA is therefore of national and international significance. It is home to plant species adapted to the acidic, low nutrient conditions - including common heather, cross-leaved heath, cotton sedges, bog asphodel, deer sedge, bog mosses (Sphagnum species) and sundews. Some of the best examples of blanket bog, particularly those in the northwest of Britain and Ireland, have micro-topographic features such as pools and hummocks that provide micro-habitats for flora and fauna. Blanket bog is also important for over-wintering birds and for breeding birds, including waders. It is a significant store for carbon and a repository of information on past environments.
Cuilcagh Mountain SAC (also Cuilcagh Mountain ASSI and Cuilcagh Ramsar site) comprises one of the most extensive areas of upland blanket bog in Northern Ireland. The area is situated at a relatively high altitude in a high rainfall area and has a wide range of features, including well-developed pool, hummock and lawn complexes, acid flushes and bog bursts. The site contains a mixture of cross-leaved heath with the bog moss Sphagnum papillosum and extensive areas of deer sedge and hare's-tail cotton sedge; there is a generally low cover of dwarf-shrubs. The nationally relatively rare bog mosses Sphagnum fuscum and S. imbricatum are present.
Cuilcagh Mountain is one of the most important upland breeding sites in Northern Ireland for the golden plover, an Irish Red Data Book species; the merlin also occurs and the bog is occasionally used for feeding by Greenland white-fronted geese.
The site also contains transitions to montane (including montane heath which is a rare and declining habitat in Northern Ireland), rock and lake habitats and it is in these that some of the rarest plants are found, particularly bryophytes. These rare plants include dwarf willow, starry saxifrage, stiff sedge, green spleenwort, Tunbridge filmy fern and club-mosses. Bryophytes include the mosses Dicranodontium asperulum and Dicranum scottianum, and the liverworts Herbertus aduncus ssp. hutchinsiae, Bazzania tricrenata, Anastrepta orcadensis, Marsupela sphacelata and Gymnomitrion crenulatum.
Parts of the deep blanket peat have been cut-over in the past and there has also been some modern mechanical extraction. However, in recent times there have been community efforts not only to limit extraction but also to restore these areas of modern cutting.
Wetlands and Lakes
Lough Atona is the only significant lake in the LCA. This is a high altitude lake within the blanket peat and has been classed by the Northern Ireland Lake Survey as a bryophyte lake of low pH, with a high level of peat stain and unproductive. There are, however, some notable aquatic invertebrates recorded within the Cuilcagh ASSI, including several alpine species such as the water beetle Dytiscus lapponicus and the water boatman Glaenocorisa propinqua.
Key Issues
General actions for UK and NI Priority Habitats and Priority Species are detailed in the Habitat Action Plans and Species Action Plans.
WOODLANDS
Issue: low woodland cover, but significant example of upland mixed ashwoods and hazel woods/scrub
Actions:
- promote actions with National Trust and Forest Sevice to enhance the biodiversity value of demesne/parkland woodland by encouraging planting of native standard trees; by preventing further loss of parkland; by retention of fallen and veteran trees (particularly for bryophytes, ferns, fungi and fauna)
- further study of the history of demesne and other broadleaved woodlands particularly any ancient and long-established, as a key to future management
- encourage control of grazing in broadleaved woodlands to foster regeneration and if necessary, encourage replanting of canopy species
GRASSLAND AND ARABLE
Issue: excellent examples of semi-natural dry grassland, including upland calcareous grasslands
Actions:
- encourage (through participation in Environmental Schemes) adoption of less intensive management of pastures to allow reversion to more species-rich grassland and protect unsown areas of species-rich grassland; ensure that there is sufficient grazing to maintain diversity of plant species
- protect limestone pavement against clearance
HEATH AND BOGS
Issue: the upland blanket bogs of Cuilcagh are of national and international importance; also important montane communities
Actions:
- maintain the integrity of existing bogs by for example, preventing, fires, new drainage and new peat cutting
- restore bog habitats through appropriate water level management and phasing out peat cutting
- continued encouragement to local community groups to work with the 'Mountain Park'
- ensure preservation of montane communities, monitoring effects of recreational use of the mountain summit
