Omagh Farmland Biodiversity Profile
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
- only one large State Forest, Seskinore, which although dominated by conifers has compartments of mixed and broadleaved woodland of greater biodiversity
- outside of Seskinore Forest, broadleaved and mixed woodland is of two main types, that in parkland and that on cut-over bog - the latter is frequently of almost pure birch wood, but around the wetter edges alder-willow wet woodland is common
- LCA dominated by improved pastures generally of low biodiversity, but level of improvement varies (some reversion to rushes) and locally flushed pockets of more diverse marshy grassland and fen
- large amount of lowland raised bog and whilst most has been cut-over and much is now colonised by birch woodland, there are significant areas of intact bog with diversity of structural features and bog flora
- rivers with Priority Species and which are important to the Foyle System as a whole
Woodlands
Seskinore Forest is the only large area of coniferous forest, with Sitka and Norway spruce dominant. However, Seskinore also contains compartments of mixed broadleaves that include oak, beech and ash, as well as compartments of pure oak and stands of old broadleaves. Some of the edge planting in the east of the forest and around the former Seskinore Lodge was present in 1833, and although most of the trees have been replaced by modern planting, the site is 'long-established' and could contain species not found in more recent woodland. Mountjoy Forest, to the north of Rash House, has a plantation of larch and Sitka spruce planted on peat and organic alluvium. Red squirrel is recorded from both Seskinore Forest and Mountjoy.
Broadleaved and mixed woodland is of two main types, that in parkland and that on cut-over bog. Woodland at Rash House (lowland woodland pasture and parkland) was present in the 1830s and can therefore be classed as 'long-established'; however, there has been heavy grazing and the herb layer is generally species-poor. The tree species are diverse; beech and sycamore are dominant, with oak, wych elm, ash and birch frequent. There is also a range of conifers that includes Wellingtonia and silver fir. At Old Mountjoy, beech and sycamore are also dominant and it also has a diversity of trees. Birch-alder woodland has developed on cut-over peat which has also been planted with conifers. Much of Ecclesville is now under conifers and some of the former parkland has been taken into the golf course and equestrian centre, but broadleaved woodland remains around the edge and includes beech, birch, oak and sycamore.
Woodland on cut-over bog is widespread in the LCA; it is dominated by birch which often forms almost pure woodland on the drier deeper peat left by cutting. Around the edge and where more peat has been removed, the ground is often wetter with more minerotrophic ground-water - willow and alder wet woodland is common. Examples of woodland on and around cut-over bogs include those at Mountjoy Forest, Old Mountjoy and Tattraconnaghty in the north and Tullyrush in the south.
Grassland and Arable
Improved grassland is the dominant land cover of the LCA. This is generally of low biodiversity because many grasslands are sown pastures (ryegrass and few other species), fertilizers and slurry are applied together with herbicides, and there is either repeated cutting for silage or heavy grazing. There is, however, variation in the level of improvement; some improved pastures are being colonized by rushes, both in drained fields in the lower lying land between drumlins, and on the drumlins themselves where there is impeded drainage.
In wetter low-lying land, where there has not been intensive drainage and where peat bogs have either not formed or have been removed by cutting, there is acid grassland dominated by rushes; it is generally of low biodiversity. Locally, flushing can lead to more species diversity in pockets of marshy grassland or fen.
Although there is little arable in the LCA and hedgerows are generally poorly managed and gappy, there is a diversity of farmland birds recorded in the LCA - probably because of the intermix of small areas of various land cover types. Priority Species recorded include bullfinch, reed bunting, skylark, song thrush, spotted flycatcher and yellowhammer.
Heaths and Bogs
This LCA contains a large amount of lowland raised bog and whilst most of it has been cut-over and much is now colonised by birch woodland, there are significant areas of intact bog. Lowland raised bog is a rare habitat in the UK, and Northern Ireland has a large proportion of that remaining; in particular it has much of the intact lowland bog. In the best examples there is a diversity of structural features including hummocks and hollows and pools that give rise to micro-habitats related especially to the height of the water table. The plant species are adapted not only to the generally waterlogged, acid and low nutrient conditions, but also to these small-scale variations in topography and water level. Typical plant species include bog mosses, deer sedge, cotton sedges, bog asphodel, sundews, cross-leaved heath and common heather.
In the northwest of the LCA, is the eastern end of the concentration of lowland raised bogs in the Fairy Water Valley (see LCA 21). The once extensive intact bog at Garvaghullion has been degraded in recent times through machine cutting and little of the intact surface remains. A poor hummock/hollow and pool complex is present and, considering the degradation, there is a good diversity of bog mosses (Sphagnum species). Tully Bog ASSI is the most easterly of the bogs in the Fairy Water valley. It is compact, relatively undisturbed and among the most intact examples in the west of Northern Ireland. The intact bog surface exhibits a well-defined dome with characteristic vegetation and structural features, including hummock and lawn complexes and small shallow pools. Sphagnum species are well represented. The cut-over surrounds have a mosaic of habitats that includes mature wet woodland, scrub, acid grasslands and regenerating bog vegetation.
In the south of the LCA, the Cranny Bogs ASSI comprises three inter-drumlin lowland raised bogs which are remarkably intact and are also among the best remaining examples in the west of Northern Ireland. The intact domes have characteristic vegetation and structural features, including small shallow pools. Notable species include the rare hummock forming mosses, Sphagnum imbricatum and Sphagnum fuscum, together with the nationally rare Sphagnum pulchrum. The woolly hair moss forms scattered hummocks over the bog and the distinctive liverwort Pleurozia purpurea is present, which is indicative of western, more oceanic bogs.
To the west of Beragh is another concentration of inter-drumlin bogs that, despite mechanical extraction, retain intact centres. The most extensive of these is at Annaghagh where a ridge across the middle divides the bog in two. The southern part is dry, with poor bog moss cover, short common heather, deer sedge, cross-leaved heath and Cladonia lichens. To the north, hummocks of the bog mosses Sphagnum papillosum and Sphagnum magellanicum are more frequent, with some wet lawns of white beak sedge and bog asphodel. These wet parts have limited amounts of Sphagnum cuspidatum and Sphagnum pulchrum.
Apart from the concentrations highlighted above, remaining intact bogs are small, not only because of the long history of past cutting, but also because modern mechanical extraction of peat has been widespread and intense. Although mechanical extraction for fuel has declined in recent years, recovery of the vegetation is slow in general and the rate of recovery of individual species varies; because cotton sedge and deer sedge recover more quickly than other species they are often dominant, indeed there is frequently little else. Species diversity has been considerably reduced.
Despite disturbance from cutting, the lowland bogs are important for breeding waders - lapwing, snipe and curlew have been recorded.
None of the lakes examined by the Northern Ireland Lake Survey were regarded as a priority for biological interest. Fen is of limited occurrence in the LCA, generally confined to narrow strips around some of the loughs. For example, Loughnagin has a fringe of bottle sedge and soft rush fen together with some reedmace and bog bean in the water's edge. Lough Muck also has some reedbed and fen. The Fairy Water, Owenreagh River, Strule River, Camowen River, Drumragh River and Quiggery Water have river water crowfoot: the otter is widespread. Several rivers are part of the Foyle system and their water quality not only affects their fish stocks, but has importance for the Foyle - particularly in relation to 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:
- enhance the biodiversity value of demesne/parkland woodland through control of grazing and felling; by encouraging planting of saplings of the 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
- encourage planting of broadleaved plantations, through appropriate grant schemes, rather than the small conifer plantations which are of poor biodiversity and landscape value
- retain wet woodlands and birch woodlands where established on cut-over bog
GRASSLAND AND ARABLE
Issue: poor biodiversity of farmland
Actions:
- maintain and improve field boundaries especially hedgerows; 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 appropriate management of pastures to allow development of more species-rich grassland and protect any unsown areas of species-rich grassland
- further survey of grasslands to ascertain better information on biodiversity - of both habitats and species
- 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: raised bogs of national and international importance
Actions:
- maintain the integrity of existing lowland raised bogs by for example, preventing infilling, fly-tipping, fires, new drainage and new peat cutting
- consider restoration of raised bog habitats through appropriate water level management, removal of individual colonizing trees and phasing out peat cutting
- prevent new forest planting/small conifer plantations on raised bog
WETLANDS
Issue: important rivers both to the LCA and in relation to the Foyle system
Actions:
- protect water quality of lakes and rivers through nutrient management and by reducing suspended sediments, 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
- monitor streams in relation to expansion of rural/urban housing and associated septic tanks/sewage treatment plants
- monitor the effects of peat cutting with regard to sediment load and deposition and pH, and its effects on fish and other aquatic life
