Portaferry and North Lecale 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

• a spine of hills extending from Downpatrick to Portaferry which rise to over 100m; some with scrub and patches of trees giving diversity to the LCA
• lower ground in farmland, mainly pasture
• several demesnes, especially around the Strangford Lough shoreline where they give a wooded aspect.

Woodlands

Approximately 3% of this LCA is occupied by trees and woodland. The majority of the woodland is associated with demesnes (Lowland woodland pasture and parkland), particularly on either side of the Narrows; on the eastern side stretching from Portaferry House to Ballyherly and on the western from Castleward to Myra Castle. Although including specimen exotic trees and some conifer plantations, these demesne woodlands are dominated by broadleaves, in particular of oak, sycamore, beech, ash and elm (though some of the latter have been lost to Dutch elm disease). In the woodlands barn owl, song thrush and red squirrel have been recorded - all of which are priority species.

Grassland and Arable

Pasture is the dominant land cover in the LCA, accounting for approx. 65% of the area. In the lower parts of the LCA, pasture is relatively high-quality improved pasture (56% of LCA total), but in the higher areas tends to be of lower productivity permanent pasture, sometimes grading into semi-natural grasslands and heath. Arable fields are intermixed with pasture throughout the lower parts of the LCA both north and south of the central spine of hills. Extensive areas of arable are rare.

Heaths and Bogs

In the past there were some small bogs between hills in the LCA, but today, as a result of past cutting, none remain. The former bog sites are now in carr (wet woodland) or have been reclaimed for agriculture.

Wetlands

Eutrophic standing waters are highly productive because plant nutrients are plentiful either naturally or as a result of artificial enrichment. They can have a high biodiversity; planktonic algae and zooplankton are abundant, submerged vegetation is diverse and there are numerous species of invertebrates and fish. Great Dam (Tullyratty) is the only example in this LCA. It has been found to contain lesser bearded stonewort which is a priority species for Northern Ireland.

Marl lakes have a high base status, a specialised flora and are generally rare in Northern Ireland; two examples are found in the LCA - Ballyherly Lough and Loughkeelan which has also been found to contain lesser bearded stonewort. There are few rivers of note in the LCA.

Fens have developed through past peat cutting or infill of small lakes. Most are small but nevertheless can be part of a rich mosaic of habitats - fen, swamp, open water, wet woodland, scrub and semi-natural grassland - and some in this LCA are particularly important for species rare to Co. Down or to Northern Ireland. These include dioecious sedge-common butterwort wetland (a rare wetland type in Co. Down) at Ardmeen, which also has the blunt flowered rush and black bog-rush, both rare in Northern Ireland. The habitats also support Priority Species such as the reed bunting.

Coastal Communities

LCA 93 is also characterised by its coastal position and there are significant areas, at the mouth of Strangford Lough, with a relatively high faunal biodiversity such as Green Island, Audleys Castle Rocks, Chapel Island Causeway and Ballyhenry Bay. These areas are dominated by fucoids such as knotted wrack and feature excellent faunal diversity due mainly to underboulder habitats. Mud snails, which graze on microscopic algae and bacteria on the surface of the mudflats, are eaten by shelduck and other waterfowl. Lugworms, ragworms, catworms, tellin shells and burrowing amphipod 'shrimps' live within the sediment. These organisms exist in enormous numbers and form an important part of the diet of the 45,000 wading birds that winter on Strangford Lough. (Strangford Lough has been designated as Northern Ireland's first Marine Nature Reserve). Small areas of coastal saltmarsh are also found along the Strangford Lough shoreline. One of the more extensive is located on the southern side of Dickson's Island where there is a clear zonation from the edge of the lough. Species present in this saltmarsh include common saltmarsh-grass, sea lavender and sea aster. Maritime grassland is found as a narrow fringe to some saltmarsh patches.

The sheltered waters, rocks and islands attract seabirds, particularly terns, black-headed gulls, black guillemots and eider duck all of which breed and feed within and close to the Lough.

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: NI Priority Habitat Lowland woodland pasture and parkland with records of NI Priority Species barn owl, song thrush and red squirrel

Actions:

• enhance the biodiversity value of demesne woodlands by discouraging any further felling or pollarding; by retention of fallen and veteran trees (particularly for bryophytes, ferns, fungi and fauna); ensure that hazel scrub is not cleared
• enhance biodiversity through measures to improve and extend woodland cover such as The Woodland Grant Scheme or The Farm Woodland Premium Scheme; management plans for demesne woodland should be directed toward their survival, through natural regrowth or planting of native broadleaf species
• encourage control of grazing in demesne woodlands to foster herb layer and regeneration and if necessary, encourage replanting of canopy species
• 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

GRASSLAND AND ARABLE

Issue: intensively managed pasture and arable dominate land cover in this LCA, but are of low biodiversity value

Actions:

• encourage (through participation in Environmental Schemes) adoption/continuance of less intensive management of pastures to allow reversion to/continuance of more species-rich grassland
• maintain and enhance any damp grassland by where, possible, restricting field or arterial drainage
• maintain and improve field boundaries, especially hedgerows where they occur through adoption of correct cutting cycles; hedge laying and replanting where necessary; leave 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
• ensure that further clearance of boulders does not occur on pastoral or arable land

WETLANDS AND LAKES

Issue: this LCA features the NI Priority Habitats eutrophic standing waters (Great Dam), marl lakes (Ballyherly Lough and Loughkeelan) and fens which support NI Priority Species

Actions:

• promote and encourage adoption of Countryside Management guidelines so that eutrophic standing waters, marl lakes and fens are not polluted by releases from silage effluent, herbicides, pesticides, fertilisers or sheep dip; ensure that further eutrophication does not occur as a result of nutrient-rich surface waters from surrounding farmland
• monitor the nutrient status of eutrophic standing waters, Marl lakes and fens; monitor streams in relation to expansion of rural/urban housing and associated septic tanks/sewage treatment plants; monitor effects of recreation, including fishing, on shoreline communities (reedbeds, fens etc.)
• prevent further loss of fen through drainage, reclamation, land-fill, new woodland planting and encroachment by scrub woodland; prevent dumping and fly-tipping and encourage removal of rubbish; care should be taken to divert the flow of nutrient rich water from agricultural land away from fens, so that sites do not become damaged by a change in species composition
• carefully assess any proposals for arterial and field drainage near to fens so that the water table is not lowered to the extent that fens are affected

COASTAL COMMUNITIES

Issue: the entire coastline of this LCA lies within Strangford Lough, Northern Ireland's first Marine Nature Reserve and features areas of relatively high faunal biodiversity; these include the NI Priority Habitat coastal saltmarsh

Actions:

• protect rare coastal saltmarsh communities from sources of pollution and waste tipping, in addition to damaging activities such as land-fill and construction
• protect mudflats and mudflat communities such as lugworms, ragworms and amphipod shrimps, from potential impacts of nutrient enrichment, land claim, coastal defences, dredging and human disturbance
• ensure that NI Priority Species, rare plants and RSPB Red List Species are protected from factors such as new development, erosion, waste tipping and pollution

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