Slievemore Biodiversity Profile
In the following account of this LCA 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 cover about 6% of the LCA, slightly above the percentage for Northern Ireland as a whole
- almost all is in coniferous State Forest of low biodiversity
- grassland covers c.76% of the LCA, around 5% more than the percentage for Northern Ireland as a whole; three-quarters is improved pasture that generally has low biodiversity
- blanket bog, a European Priority Habitat, is extensive on the spinal plateau, but a considerable proportion has been cut-over, much has been afforested and intact bog has been reduced in recent times by mechanical extraction
- upland heathland is scattered, but not extensive
- low presence of wetlands, but possible opportunities for creation of wetland habitats in worked-out sand and gravel quarries
Woodlands
Woodlands cover about 6% of the LCA, slightly above the percentage for Northern Ireland as a whole. Almost all is in coniferous State Forest, Pomeroy, Altmore and Dunmoyle Forests, planted on blanket peat and peaty soils. These forests are dominated by Sitka spruce with lodgepole pine, Japanses larch and Norway spruce and generally have low biodiversity - and may be lower than some of the blanket peatland they have replaced. There are small mixed and broadleaved patches; some are modern planting, some are from semi-natural scrub alongside streams and others are from earlier planting around small estates and hunting lodges. However, in Pomeroy Forest the contribution of broadleaves is greater; here there are modern broadleaved compartments but also the Pomeroy FNR. This consists of two woodland types - old estate woodland planted between 1780 and 1830 composed of mixed deciduous woodland and virtually pure Scots pine (lowland woodland pasture and parkland), and birch and willow scrub that has colonised a former cut-over bog (wet woodland)
The only other broadleaved woodland of note in the LCA is Glenmore Wood ASSI an acid, but in parts flushed, woodland on slopes of the deeply incised Glenmore Valley. The wood merges into scrub and acid grassland on the north side of the valley. The acid woodland is dominated by sessile oak with downy birch as its main associate species in the canopy (upland oakwood). The understorey is mainly hazel and the herb layer is dominated by greater wood-rush; the presence of bilberry in parts emphasises the acidic nature of the soils. Where the woodland is flushed, that is there is mobile, mineral-rich water, ash, alder and willows are characteristic and the herb layer is more diverse, including wood anemone, opposite-leaved golden saxifrage, bugle and lesser celandine.
Small pockets of scrub and low woodland are scattered through the LCA where former small cut-over bogs have become colonised by birch and where there are short steep slopes alongside streams. Although of little interest individually, these pockets in addition to adding plant species diversity to the countryside generally, provide habitats for mammals, birds and insects.
Grassland and Arable
Grassland covers c.76% of the LCA, around 5% more than the percentage for Northern Ireland as a whole. Of this three-quarters is improved pasture that generally has 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. In this LCA, the degree of improvement and intensity of management varies so that although low, there is some variation in the biodiversity. Arable land is insignificant in the LCA.
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 this LCA, hedges are confined to the lower land with improved pastures, but even here they are not maintained well and are gappy. With increase in altitude hawthorn gives way to gorse and fence-and-wire.
Despite the dominance of improved pastures in the lower lands it is intermixed with hedges, small woodland patches, occasional arable fields and pockets of damp grassland so that there are habitats for several Priority Species - including song thrush, yellowhammer, linnet, skylark, reed bunting, spotted flycatcher and curlew.
Almost all the rough grassland in the LCA is acid grassland on cut-over peatland or on wet soils derived from acid tills. These grasslands are not usually diverse in plant species although in cut-over areas changes in peat depth can lead to small-scale variation in habitats and greater species diversity with bog plants and heath plants on wetter and drier sites. Although some of the acid grasslands are found on small cut-over bogs in the lowlands, most are on the margins of the spinal upland plateau that trends from southwest to northeast. Breeding waders, lapwing, curlew and snipe, have been recorded from these upland grasslands.
Heaths and Bogs
Blanket bog is extensive on the spinal plateau, but a considerable proportion has been cut-over and much has been afforested. The former Gortfinbar Bog was described in the mid-1950s as an area of about 1600 acres (650ha) of virgin bog. Today it is mainly occupied by Altmore Forest with intact bog surviving only to the northeast and northwest of the forest, apart from small patches isolated in an expanse of cut-over on the south side.
To the west of Altmore and extending to Slievemore and Slievedivina is a vast area of cut-over bog with scattered small intact remnants. The only relatively large intact area (c.27ha) was, until the 1980s, to the west of Black Lough, but since that time it has been lost to extensive machine cutting. Machine cutting is distributed throughout the blanket bog and several of the incidences have been large. The biodiversity of the blanket bog has been reduced considerably by loss of both species and habitats.
In Europe, blanket bogs are confined to the northwest margins of the continent so that the blanket bogs of Ireland and of Northern Ireland are of international importance, and particularly those bogs that are intact. Losses from forestry and modern cutting, especially on the scale that has occurred in this LCA, are therefore particularly regrettable.
Lowland raised bog occurs to the north of the Altanagh River, although the boundary between blanket and raised bog is difficult to draw because the cut-over blanket bog merges with the lowlands. An example is the bog to the north of Shane Barnagh's Sentry Box which had the appearance of raised bog although situated on a shelf above 200m in altitude. That site, like others with an intact core, has largely been lost to machine extraction.
Upland heathland is scattered, but not extensive, through the upland margins either where drier sites have been left in cut-over bog or on slopes too steep for peat to accumulate. Common heather dominates.
Wetlands and Lakes
Cavanacaw Lake has been classified as a mesotrophic lake. Mesotrophic lakes, that is, characterised by having a middle level of nutrients between nutrient poor (oligotrophic) and nutrient rich (eutrophic), potentially have the highest macrophyte diversity of any lake type. Furthermore, relative to other lake types, they contain a higher proportion of nationally scarce and rare aquatic plants. This is an increasingly rare type of lake in Northern Ireland because the nutrient status of many is being increased through input of water from agricultural land that has had applications of fertilizers and slurry. However, within this type, Cavanacaw is regarded as of low priority. None of the other lakes in the LCA have been classified as of importance to biodiversity.
Altmore Lower Reservoir and Cavanacaw Lake have associated fen communities.
Apart from the otter, which is widespread, there are no records of other Priority Species in the rivers and streams.
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 native broadleaved woodland cover
Action:
- encourage planting of native broadleaved woodlands, through appropriate grant schemes, rather than conifer plantations which are of poor biodiversity and landscape value.
GRASSLAND AND ARABLE
Issue: poor biodiversity of farmland
Actions:
- maintain and improve field boundaries especially hedgerows - where traditional in the landscape. This may be achieved through adoption of correct cutting cycles; hedge laying and replanting where necessary; leaving saplings uncut to develop into hedgerow trees; avoidance of spraying with fertilizers, slurry, herbicides; provision of wildlife strips and conservation headlands around fields; and limitation of field amalgamation
- 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
- promote research into grasslands to locate any areas of species-rich grassland
- maintain and enhance damp lowland grassland by restricting field or arterial drainage
- leave stubble over winter, rather than autumn ploughing, to increase food resources for farmland birds; spring sown cereals are beneficial to breeding farmland birds.
HEATH AND BOGS
Issue: need to preserve upland heathland and halt decline in its biodiversity
Actions:
- promote membership of ESA and other environmental schemes through consultation with farmers and thereby
- control grazing intensity on existing heathland to encourage development of heathland and of heather of different ages
- discourage 'reclamation' to pasture fields around the heathland margins
- discourage afforestation
Issue: raised bogs/blanket bogs are of national and international importance, particularly any remaining intact bog
Actions:
- maintain the integrity of existing intact lowland raised bogs and blanket bogs by for example, preventing infilling, fly-tipping, fires, new drainage and new peat cutting
- restore raised bog habitats through appropriate water level management, tree removal (individual colonisers) and phasing out peat cutting
- restore examples of blanket bog through similar measures
- prevent new forest planting on raised/blanket bog
WETLANDS
Issue: continued need to protect rivers and lakes from eutrophication and excessive sediment deposition
Actions:
- protect water quality of lakes and rivers through nutrient management and by ensuring that suspended sediment load and deposition does not affect plant and animal life, thus
- promote and encourage existing good farming practices so that streams are not polluted by run-off from agricultural land or seepage from silage pits
- continued monitoring of streams below industrial plants and sand quarries
- monitor effects of peat cutting on sediment loads and deposition
- monitor streams in relation to expansion of rural/urban housing and associated septic tanks/sewage treatment plants
Issue: very little fen or reedbed in the LCA
Action:
- many sand and gravel quarries in the area which, upon completion of working life, could be considered as sites to create wetland environments - suitable grading of depths could give open water, reedbeds, fen and wet woodland.
