Bessy Bell and Gortin Biodiversity Profile

Last updated: 8 February 2010
 

In the following account it should be noted that for consistency, the biodiversity section follows the standard order for all LCAs even though some of the communities discussed later may have more importance for biodiversity than those discussed earlier

Key Characteristics Woodlands

Woodlands are about 12% of the land cover, almost twice the percentage for Northern Ireland as a whole (c.5.6%); the majority is coniferous woodland established on the high ground to both the east and west of the Strule valley. Gortin Glen Forest in the east is dominated by Sitka spruce with lodgepole pine, Japanese larch and Norway spruce generally in large compartments, but in the centre compartments become small, highly varied and include some hardwoods. Broadleaved trees and scrub are also included along some of the rivers, for example the Glengawna Burn. These small patches add some biodiversity to the forest that as a whole is of low biodiversity. Interest is also increased by a wildfowl area and a small herd of Sitka deer. In the southeast, Killens Forest is also mainly Sitka spruce and lodgepole pine with hybrid larch at the lowest tip of the forest.

To the west, State coniferous forest is found on the western slopes of Bessy Bell, on Mullaghcroy and to the west of the Barons Court estate; Sitka spruce dominates. Much of the Barons Court estate is in conifers, but there are also extensive mature and young broadleaved and mixed woodlands together with parkland (lowland woodland pasture and parkland). Trees include oaks, beech, sycamore, lime, ash and birch with hazel, rhododendron and cherry laurel in the understorey.

At Old Mountjoy, beech and sycamore are dominant in a diversity of trees. Birch-alder woodland has developed on cut-over peat which has also been planted with conifers. Mountfield Lodge has little parkland remaining, apart from around the house most of the land has been planted and joins with Killins Wood. Larch, beech and Sitka spruce are the most abundant species but there is a very wide range of tree species, both conifers and broadleaves.

Small conifer plantations of around 1ha or less are widely scattered through the LCA; they have no biodiversity value.

Broadleaved woodland accounts for only a fifth of the total woodland, nevertheless, in addition to estate woodland, it includes some important and quite large sites. In the north, to the west of Gortin, is a group of woodlands centred on Birch Bank, Lecky Burn and Rylands Burn. These woodlands are dominated by oak (upland oakwood) but with abundant birch; the presence of beech, larch and other conifers indicate that the woodlands have been 'landscaped'. In general the woodlands are heavily grazed and the herb layer is poor in consequence or dominated by grasses. However, along the Lecky Burn the herb layer is diverse, in part depending on the soil conditions, and includes woodrush, bluebell, oxalis, wood anemone, pignut and a wide range of ferns. Epiphytic mosses and lichens are abundant in most of these woodland patches. All of these woodlands were present in 1830, so that they are at least 'long-established' and may be 'ancient'; such woodlands are thought to be rare in Northern Ireland and may contain species not found in more recent woods.

East of Gortin there is another group of small upland oak woodlands alongside streams and also Boorin Wood. Although as a whole the wood is an upland oakwood, only the southern, uppermost part falls within this LCA. In this part the wood is extending into the heath developed over the sands and gravels of the moraine and is principally of birch with heather beneath (Boorin Wood NNR).

Birch woodland is common in the LCA, sometimes mixed with hazel or with oak on steep valley sides, at other places in association with willow and alder, and also as almost pure communities on cut-over bog. The steep sides of the Glensawisk Burn are an example of hazel-birch woodland and scrub and demonstrate its variability; in parts the herb layer is poor and grass dominated, but in others, where the mineral soils are more base-rich, it is diverse. The Gortin Burn is similar whereas at Carrigans on the flat land beside the R. Strule, the wet mineral soils have given rise to woodland of birch, mountain ash and alder. Examples of almost pure birch woodland on cut-over bog can be seen east of the R. Strule in the Tantramurry-Tattynure-Golan area.

Upland mixed ashwoods are localised, generally mixed with hazel and sometimes with oak. That along the Cappagh Burn is one of the largest (10ha) and displays a range of trees including some beech that indicates a degree of planting, although the woodland was present in 1830. The varied ground conditions, with wetter parts, give rise to a diverse herb layer although the total cover is relatively low as a result of grazing. Woodland along the Glengowna Burn is similar but with the addition of oak to the canopy.

Hazel is a common constituent of many of the woodland types in this LCA, not only birch woodlands and ash woodland, but also in association with oak as at Altdoghal Burn. It also forms almost pure stands - usually as small patches on steep slopes, at the sides of streams or on meander scars. Grange Wood ASSI has a range of woodland types and in consequence has one of the richest plant assemblages in the LCA. The wood occurs on the north-eastern flank of Bessy Bell Mountain and partially lies over an isolated outcrop of Dungiven limestone. This gives it a calcareous nature that is more characteristic of County Fermanagh. The wood is largely comprised of a low, multi-stooled hazel canopy with occasional ash standards over a diverse base-rich ground flora. Frequent exposed rocky outcrops and boulders are covered by a luxuriant growth of mosses, particularly on the upper slopes. The lower slopes are waterlogged with extensive flushing and in these areas willow and alder predominate in wet woodland.

Grassland and Arable

Grassland accounts for about 67% of the land cover, slightly less than the percentage for Northern Ireland as a whole. Around two-thirds of the grassland is improved pastures. These have generally low biodiversity as a result of relatively intensive management. Some of the pastures are sown grasslands dominated by ryegrass and few other species - low biodiversity is in-built. Other grasslands have been converted to improved pastures through management. High levels of grazing or repeated cutting for silage, high inputs of fertilizers and slurry, and selective herbicides serve to reduce diversity of both flora and fauna. Arable land is less than 3% of the LCA and tends to concentrate along the Strule valley where soils are better drained, especially in the narrower section between Bessy Bell to the west and Deers Leap to the east.

Biodiversity in areas of improved pastures and arable is often concentrated in hedgerows. Indeed, they may be the most significant wildlife habitat over much of lowland Northern Ireland, especially where there are few semi-natural habitats. Hedgerows are a refuge for many woodland and farmland plants and animals. In the lowland parts of this LCA field boundaries include hedgerows and wire fences; although often heavily treed, many hedgerows are poorly managed and have become overgrown and gappy. In other parts they have been severely cut and sometimes removed, to be replaced by wire. However, there are stretches of well-maintained hedges where the dense cover provides habitats for farmland birds and plants that thrive in the semi-shade.

picture of a yellowhammerThe foothills of the mountains and the lower hills, where not occupied by forest, are generally in rough grassland that is dominated by rushes and is of low biodiversity. This changes upslope into acid grassland and heath. The slopes of the mountains in this LCA are steep and this has prevented the accumulation of deep peat; in addition, where peat occurs most has been cut-over, large expanses have been drained, notably the southeast slopes of Mullaghcarn, and there has been variation in the level of grazing with some areas carrying a heavy stocking rate. Typical blanket peat vegetation is therefore limited on the slopes (see below); acid grassland dominates, with some heather where grazing intensity has not been so high.

Despite the dominance of improved pastures, the mosaic of land cover types within the lowlands - rough grassland, arable, woods, heath, hedgerows - has led to the presence of many of the bird Priority Species. Bullfinch, linnet, reed bunting, skylark, song thrush, spotted fly-catcher and yellowhammer are recorded.

Heaths and Bogs

In several parts of the mountains, steep slopes have prevented the development of deep peat and they have become dominated by common heather. Some of the heather areas are upland heathland, but they grade into areas where the peat, although relatively shallow, is more than 50cm in depth, the maximum depth for an area to be classed as upland heathland. A large part of the summit ridge extending from Liscabble Mt. to Curraghchoslay Mt. is dominated by heather, as are large parts of the north slopes of Mullaghcarn, and the upper parts of Bessy Bell. Other steep slopes have patches of gorse heath.

The Gortin moraine at Boorin is covered by a mosaic of bog, flushes, acid grassland and heath (Boorin NNR). The well-drained parts are dominated by common heather whereas the lower lying wetter sections have purple moor grass; wet hollows have bog, but most has been cut-over, and flushes can be recognized by the presence of soft rush. The heath has probably been maintained in the past by burning to promote red grouse; this relatively rare species occurs in areas of upland heath in the LCA including on Mullaghcarn. Upland heathland has been a declining habitat in Northern Ireland, Ireland and the UK as a result of afforestation, reclamation to pasture and overgrazing so that example in this LCA are of national significance.

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. It is also important for over-wintering birds and for breeding birds, including waders. Blanket peat is also significant as a store for carbon and as a repository of information on past environments.

picture of a snipeIn the LCA blanket peat tends to be relatively shallow because of the steep slopes and past cutting. Almost all of the blanket peat has been cut-over in the past and large areas on the east of Mullaghcarn have also been drained. Modern compact-harvester cutting has been widespread, particularly along the slopes overlooking the Glensawisk Burn and also has occurred near to Boorin NNR. The only sizeable areas of intact bog occur on high spurs above Upper Magheraliss, but there are no extensive pool or hummock complexes and much of the peat is relatively dry and dominated by common heather.

There is no intact lowland raised bog in the LCA; the small bogs have all been cut-over in the past (some with modern mechanical extraction too). Several have been colonized by birch and some have small conifer plantations. However, these small bogs and the wet pastures that adjoin them are important for waders - curlew, lapwing and snipe have been recorded.

Wetlands and Lakes

Of the seven lakes examined by the Northern Ireland Lake Survey, two were classed as mesotorphic lakes, but of a low priority type with silty sediments and moderately enriched. Both of these lakes, Fanny Lough and Lough Catherine, have associated fen and reedbed communities present. Oak Lough (Boorin) is a peaty, low pH lake with bryophytes and is typical of lakes occurring in peatlands. The Strule River has river water crowfoot and as part of the Foyle system, is important for Atlantic salmon.

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 of variable biodiversity value

Actions:

GRASSLAND AND ARABLE

Issue: poor biodiversity of farmland

Actions:

HEATH AND BOGS

Issue: loss of upland heathland and decline in its biodiversity

Actions:

Issue: blanket bogs are of national and international importance

Actions:

WETLANDS

Issue: mesotrophic lakes present, a declining lake type due to enrichment, and rivers with Priority Species and salmon

Actions:

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