Derry Slopes 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

• woodlands account for less than 1% of the land cover, almost entirely associated with estate lands
• grassland covers about 62% of the land, lower than the percentage for Northern Ireland as a whole (c. 71%) as a result of the large area occupied by the city of Derry
• around two-thirds of the grassland is improved pasture - generally of low biodiversitysmall amount of upland heathland, a declining habitat in the UK and Ireland
• River Foyle of national and international importance for Atlantic salmon

Woodlands

Woodlands account for less than 1% of the land cover, almost entirely associated with estate lands that include Mullenan House, Spring Grove, Creevagh House, and the concentration that extends from the northeast of the city along the lough shore and encompasses Brook Hall, Thornhill College and Ballynagard House (lowland woodland pasture and parkland). Almost all of these estate woodlands were present in 1831, so that they are at least 'long-established' and may therefore contain species of the herb layer and of mosses and lichens that are not common in more recent woodlands. Trees are typical of estate woods, including beech, sycamore ash and some elm. Brook Hall is the centre of a bio-energy project based on coppiced willow. Other woodlands in the LCA are very small and confined to steep slopes alongside small streams as below Nixon's Corner.

The Woodland Trust has recently established small woodlands around Derry that may help to increase future biodiversity, especially of the urban area. Examples are Southway Community Woodland - planted with oak, ash, rowan and cherry - and Ballyarnet oak/wet woodland, where species include oak, ash, alder and birch.

Grassland and Arable

Grassland covers about 62% of the land, lower than the percentage for Northern Ireland as a whole (c. 71%) as a result of the large area occupied by the city of Derry. Around two-thirds of the grassland is improved pasture. This 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. Arable land is about 10% of the land cover and is concentrated on flatter land in the south and the north where the soils are predominantly well-drained brown earths.

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 however, the farmland is relatively open, with only occasional hedgerow trees; broken stone walls as well as hedgerows surround many of the fields, particularly to the north of the Skeoge valley.

Rough grassland is common on the outskirts of Derry, possibly as a result of urban blight whereby land becomes unmanaged with the prospect of further urban expansion. Rough pastures and acid grassland is also common on the gentle slopes of Minkey Hill and Ballymagrorty where field size is much smaller than on the low flat lands in the south and north. These fields are generally of low biodiversity, often with a high cover of rushes, but have some importance for wetland birds - snipe have been recorded in this part of the LCA. The mix of improved grasslands and a small amount of arable with these damp grasslands has also provided habitats for linnet, yellowhammer, song thrush and skylark.

Heaths and Bogs

Blanket bog is virtually absent from the LCA with the uplands of Holywell Hill and Minkey Hill covered by thin peat and peaty soils with boulders; upland heathland, dominated by common heather occupies these hills. Upland heathland is a declining habitat in Ireland and in the UK, partly due to overgrazing in the recent past as well as to lack of active management to encourage heather regeneration.

Wetlands and Lakes

There are no significant fens or reed beds in the LCA and none of the lakes examined by the Northern Ireland Lake Survey were of high interest for conservation. The R. Foyle is an important river for Atlantic salmon.

Coastal

The narrow shore of the River Foyle is very sheltered and has a limited amount of saltmarsh, but it is of low species diversity. There are also some small patches of coastal mudflat.

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 and ecology 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 along streams to foster regeneration and if necessary, encourage replanting of canopy species
• encourage planting of native broadleaved woodland through appropriate grant schemes

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 less intensive management of pastures to allow reversion to more species-rich grassland and protect unsown areas - wet grasslands on hills may be poor in plant diversity but can be habitats for wetland birds
• 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: loss of upland heathland and decline in its biodiversity

Actions:

• promote membership of 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
• control gazing intensity on some upland grassland to promote return to heathland
• discourage 'reclamation' to pasture fields around the heathland margins
• discourage afforestation

WETLANDS

Issue: important river - R. Foyle - particularly for Atlantic salmon

Actions:

• protect water quality of rivers, 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
• encourage existing cross-border links to ensure maintenance of water quality and management of the Foyle system

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