Carrigatuke Hills 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
- extensive conifer plantations and residual blanket peat create a series of geometric blocks on the hills of the south-centre and west
- some planted, landscaped, deep wooded valleys
- many shelter-belts and small woodlands on lower hills
- fens and damp grasslands in hollows in the lowlands; fens probably of greatest interest to biodiversity in this LCA
Woodlands
Woodlands account for about 5% of the land cover of the LCA, the vast majority of which is coniferous forest located in the uplands of the south-centre and west. These forests have been planted predominantly on peat but extend onto peaty and gleyed soils. Sitka spruce is the dominant species with Norway spruce, lodgepole pine and Japanese larch also common. Coniferous forests, here as elsewhere, have low biodiversity because of their limited species and simple structure; however, red squirrel has been recorded in several of the forests.
Three forests have been centred on former estates, Drumbanagher, Carnagh and Ballymoyer Forests. Whereas conifers are dominant in these, at Drumbanagher there are intermixed areas of conifers with oak and sycamore, and in the southern tip of the forest a section of beech and oak. At Carnagh Forest (Carnagh FNR) there is a small area of estate woodland located around the hotel consisting of beech, ash and oak. The ground flora is limited because of colonisation by rhododendron and salmonberry, relics from the estate sporting interests. In addition, adjacent to the lakes there is an extensive natural mature birch woodland with willow scrub on the outermost edges. A few beech and oak trees are also present. Beneath the birch canopy the ground flora is purple moor grass dominated with areas of bilberry and bramble, Yorkshire fog and wood sorrel. The woodland is particularly good for epiphytic lichens and mosses.
Ballymoyer Forest is part of a former demesne; this wooded glen was one of the first properties to be donated to the National Trust. Today, Norway spruce and European larch dominate. Conifers are mixed with beech in the southern leg of forest, and sycamore and oak are located in pockets in the section of forest alongside the main road. Maytone House and Glen Anne provide another example of a wooded glen, planted in the nineteenth century, principally in mixed conifers and broadleaves. (Lowland woodland pasture and parkland). Wooded areas in other estates in the LCA have either been removed or have become very degraded, but there are several large gardens and small parks in the LCA, some with a diversity of tree species.
Much of the semi-natural woodland is sparse, degraded and in small patches on rocky hillsides, for example Ballintate Wood has oak and ash in an area of blackthorn and gorse scrub, but it is heavily grazed. The only other widespread woodland type is wet woodland, generally carr woodland of willow, sometimes with alder, that is colonising fen. This is found not only on the more extensive fens, but also on many of the small fen patches in hollows within and between rocky ridges, especially in the south of the LCA.
Small conifer plantations, less than 1ha and generally of Sitka spruce and larch, are common throughout the LCA. Shelterbelts around active and abandoned farms are also very common; sycamore, ash and Sitka spruce are the most frequent species.
Grassland and Arable
Grassland covers over 80% of the LCA, the vast majority in improved pastures. These have low biodiversity as a result of their intensive management, although the level of management changes through the LCA depending on factors of the physical environment as well as on practices of farmers. Land classed as arable (includes grass reseeding) is scattered throughout the lower parts of the LCA, but is nowhere extensive and is of low biodiversity interest. Field boundaries, which often have most of the biodiversity interest in areas of improved pastures and arable, are varied, with stone walls, hedges and fences, and most commonly, combinations of these. Generally, hedges are poorly managed, gappy and overgrown; nevertheless in places, for example at field corners and steep banks, shrubs and trees (predominantly ash) provide thickets which not only give a well-wooded appearance to the landscape but are valuable for birds and other wild life.
Rough grassland is common in the uplands of the south-centre and west of the LCA, surrounding the conifer forests. Soils are peaty or on steeper slopes are shallow with a thin organic surface layer; these rough grasslands tend to be acidic. Elsewhere, rough grasslands are found in damp hollows, often alongside fens or where fens have been drained. Some of these wet grasslands and fen meadows are species rich (lowland meadows) but are under threats from drainage, heavy grazing and eutrophication. Along with adjacent fens, these grasslands are home to waders, including curlew. Species-rich dry grasslands are found in the LCA, as for example on the northwest slopes of Black Hill, but some are also under threat from grazing pressures. Areas of both wet and dry rough grasslands are associated with heath, sometimes of gorse, but also of heather. The Irish Hare finds refuge in these less-managed grasslands.
Lowland, less-managed grasslands are relatively rare in Northern Ireland and in this LCA. It is important that they are not lost through reclamation and more intensive management, heavy grazing or eutrophication. Adoption of farming guidelines associated with ESA and other Countryside Management schemes should be encouraged. It should be noted also that land-fill and rubbish dumping affect not only fens but damp grasslands alongside, either directly or through leakage of nutrient rich waters.
Heaths and Bogs
Blanket bog is confined to uplands in the south-centre and west of the LCA; east of Tullyogallaghan the landscape changes as the rocky country associated with the northern edge of the ring-dyke is reached. There the rocky slopes have peaty soils with heather, gorse and bracken rather than peat vegetation; lowland peat is found in smaller patches in valleys between the hills.
Much of the blanket peatland has been forested and that unplanted has largely been cut-over. Former cut-over bogs have also been used as refuse tips. To the east of Newtownhamilton there is some intact bog at Cold Brae Bog and at Carrickacullion, set in extensive cut-over blanket bog. These have plant species typical of intact bog, including heather, deer and cotton sedges and the bog mosses.
There are no extensive examples of intact lowland raised bog in the LCA, all former bogs have been cut-over and are dominated by fen or carr woodland or have been reclaimed for pasture. At Crossdened the northern end of the cut-over bog has experienced recent peat extraction (milling) leaving large areas of bare or poorly vegetated peat. As with blanket bog, some areas of cut-over lowland bog are used as refuse tips. Fly-tipping is common, both of household goods and general rubble.
Intact peat bogs, whether lowland or blanket, are important European habitats, are relatively rare in Northern Ireland, and also very rare in this LCA. It is therefore essential that the few remnants should be retained, not only as rare habitats with specific plant associations, but for their fauna, including breeding waders such as snipe and curlew. State planting of these bogs is no longer an issue as the Forestry Service has a presumption against new planting, however new coniferous plantations limit biodiversity.
Cut-over bog can have great diversity of habitats as a result of the different depths of peat that are left and the differing water levels. For example, drier islands of deeper peat left uncut can become dominated by common heather whereas other wetter sites where the acid peat has been removed may develop into fen and carr. The biodiversity of sites - both of habitats and species - should be taken into account before they are used for peat extraction, refuse tips or other uses (see also wetlands below).
Wetlands and Lakes
Fens are frequent in this LCA and probably of greatest importance to its biodiversity. Most have a past history of cutting for fuel peat and draining for agriculture. As a result, water levels and acidity/alkalinity vary across the sites giving rise to diverse habitats and complicated mosaics of plant communities. Many of the fens are dominated by soft rush, but there are areas of floating mats of vegetation with bottle sedge and creeping bent, areas of sharp flowered rush that are generally species-poor, patches of drier acid peat with heather and acid grasses or with cotton sedge, scattered small pools with bog bean, and the edges may merge into wet rushy grassland grazed by cattle. Fens around lough margins may have common reed or reed canary grass. Where nutrient enrichment has taken place, reedmace may dominate; yet other areas may be colonised by willow.
This diversity of habitats and plant species has led to diversity of invertebrates; thus there are many species of dragonflies and damselflies, including the rare Irish damselfly, and butterflies - for example the marsh fritillary has been recorded at Drumcarn ASSI
There are a number of lakes in the LCA that are of importance to biodiversity, not only because of the mesotrophic lakes themselves, but because they form part of the diverse habitats found at a site. For example at both Crossbane Lough ASSI and Straghans Lough ASSI there are fens types, reed swamp and wet grasslands in addition to the open water and lough edge communities. Sites therefore have Priority Species associated with surrounding habitats rather than the loughs themselves, as for example the narrow-bordered hawk moth and marsh fritillary butterfly found at Straghans Lough ASSI.
Several of the lakes in the LCA have been classed as mesotrophic, that is, characterised by having a middle level of nutrients between nutrient poor (oligotrophic) and nutrient rich (eutrophic). Mesotrophic lakes 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.
Both the White Water and Cusher Rivers have river water-crowfoot and the otter is recorded in several rivers.
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 predominantly coniferous forests and poor biodiversity value; however this LCA also contains the NI Priority Habitats Lowland Woodland Pasture and Parkland and wet woodland
Actions:
- enhance the biodiversity value of broadleaved woodlands within Drumbanagher, Carnagh and Ballymoyer Forests by discouraging felling; by preventing loss of broadleaved woodlands; by retention of fallen and veteran trees (particularly for bryophytes, ferns, fungi and fauna); consider replanting of broadleaved species on felling of conifer plantations possibly through appropriate grant schemes - selective felling of conifers could leave the broadleaves in inter-mixed plantings
- encourage control of grazing in broadleaved woodlands to foster herb layer and regeneration and if necessary, encourage replanting of canopy species; remove rhododendron and salmonberry where colonisation has taken place but ensure that hazel scrub is not cleared
- further study of the history and ecology of broadleaved woodlands within the LCA, particularly any ancient and long-established, as a key to future management; monitor sites
- prevent loss of willow and alder carr woodlands through drainage, reclamation, landfill or dumping/tipping
GRASSLAND AND ARABLE
Issue: both grasslands and arable have low biodiversity value due to intensive management but include species-rich NI Priority Habitat lowland meadows
Actions:
- encourage (through participation in Environmental Schemes adoption/continuance of less intensive management of grasslands and arable to allow reversion to/continuance of more species-rich grassland and protect unsown areas including dry, calcareous grassland
- maintain and enhance less managed lowland grasslands by where, possible, restricting field or arterial drainage, reclamation, landfill and dumping, heavy grazing and eutrophication from surrounding agricultural land and farmsteads
- maintain and improve field boundaries, especially hedgerows where they occur through adoption of correct cutting cycles; hedge laying and replanting where necessary; leaving saplings uncut to develop into hedgerow trees; avoidance of spraying with fertilisers, slurry, herbicides; provision of wildlife strips and conservation headlands around fields; and limitation of field amalgamation
- leave stubble over winter, rather than autumn ploughing to increase food resources for farmland birds; spring-sown cereals are beneficial to farmland birds
HEATHS AND BOGS
Issue: this LCA contains rare examples of the NI Priority Habitats Blanket Bog and Lowland Raised Bog, with limited areas of intact bog at Cold Brae and Carrickacullion.
Actions:
- maintain the integrity of intact blanket and raised bogs by for example, preventing infilling, fly-tipping, fires, new drainage and mechanised peat cutting - applies particularly to intact bogs but cut-over bogs can provide important habitats for birds and invertebrates
- consider restoring peat bog habitats through appropriate water level management, removal of individual colonising trees and phasing out peat cutting - applies particularly to any areas of recent mechanical cutting
- prevent new private forestry planting or reclamation for pasture on former bog
- monitor the effects of drainage, fertiliser applications and felling on the water tables and nutrient levels of adjacent peatland; take full account of the biodiversity of peatland habitats and sites when considering new land use applications
WETLANDS AND LAKES
Issue: NI Priority Habitats fens and mesotrophic lakes are frequent in this LCA and contribute greatly to the area's biodiversity; a number of invertebrate NI Priority Species are present.
Actions:
- protect the water quality of fens, lakes and rivers through nutrient management and by reducing suspended sediments; prevent particles being released through peat cutting or forestry operations; install sediment traps at large extraction sites
- promote and encourage existing good farming practices so that wetlands, lakes and rivers are not polluted by releases from silage effluent, herbicides, pesticides, fertilisers or sheep dip; it is essential that nutrient enrichment of mesotrophic lakes from agricultural and other sources is prevented
- monitor the White Water and Cusher Rivers in relation to peat cutting (sediment load and deposition) - important for salmon that nursery and spawning beds are clear; monitor streams in relation to expansion of rural/urban housing and associated septic tanks/sewage treatment plants; recognise that monitoring of streams in relation to forestry and other operations upstream may also be important