Garron Plateau 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 12% of the LCA, more than double the Northern Ireland average
• almost all the woodland is in coniferous forest planted on former peatland
• grassland accounts for c. 45% of the land cover, almost all in upland and acid grassland - but percentage of the land cover difficult to ascertain because it grades into peatland
• one of the most extensive areas in Northern Ireland of blanket peatland generally unaffected by human activity; of national and international significance

Woodlands

Woodlands cover more than 12% of the LCA, just more than double the average for Northern Ireland. However, except for a few broadleaves in the upper part of Glenariff Glen (oak, hazel, ash and willow), small portions of Longmore Wood (see LCA 117) and of Drumnasole woods (see LCA 123), and scattered clumps of mixed hardwoods in the Breckagh headwaters of Cleggan Forest, all the woodland on the plateau is coniferous and State Forest.

In both the portion of Genariff Forest that is in LCA122 and in Cleggan Forest, Sitka spruce is overwhelmingly dominant; there is some lodgepole pine and hybrid larch. The biodiversity of these forests is low - much lower than the peatlands they have replaced; red squirrel in Glenarrif Forest is the only recorded Priority Species.

Grassland and Arable

Grassland accounts for around 45% of the land cover; however, this percentage is uncertain because marginal and upland acid grassland grades into peatland. The marginal upland grassland is generally of low biodiversity, but at Gortnagory ASSI there is a colony of the nationally rare orchid Irish lady's tresses - its only high altitude (upland grassland) site in Northern Ireland.

About 5% of the land cover is classed as improved grassland; this occurs principally along the southern and eastern edges of the LCA, but this too is difficult to classify because it overlaps with productive semi-natural grassland on base-rich soils.

Heaths and Bogs

The Garron Plateau cSAC (also Garron Plateau ASSI and Ramsar site) is the most extensive area of intact upland blanket bog in Northern Ireland. Blanket bog is confined in Europe to its north-western margins so that Northern Ireland examples, and particularly those that are relatively undisturbed, are of international importance. The plateau is a mosaic of raised bogs, between which there are flushed areas, drier and thinner blanket peat, and wet heath and acid grassland. There are also oligotrophic lakes.

The raised bogs have well-developed pool and hummock complexes with some large open pools in which the only plants are bog bean; other pools have a sequence of bog mosses (Sphagnum species) related to their height above the water table. Some high hummocks are dominated by woolly hair moss. The vegetation of the general bog surface is typical of upland blanket bog and includes cross-leaved heath, common cotton sedge, bog asphodel, common heather, deer sedge and hare's-tail cotton sedge; there is high cover of Sphagnum papillosum, S. fuscum and S. imbricatum. In addition to typical species, these deeper peat areas of Garron are the main Irish location for both few-flowered sedge and tall bog-sedge.

The areas of flushed peat (less acidic and more-available nutrients) are characterised by dioecious sedge and common butterwort, and are generally species-rich with a range of small sedges, including flea sedge, tawny sedge and yellow-sedge and a relatively rare easterly location for black bog-rush. Herbs include eyebright, marsh lousewort and devil's-bit scabious. Lesser clubmoss is present and there is generally a high diversity of mosses. Garron Plateau is the only locality for yellow marsh saxifrage and bog orchid in Northern Ireland. Alongside streams, purple moor grass may become dominant.

On the steeper slopes of hills within the plateau, peat becomes thinner, dominated by common heather and merges into wet heath (upland heathland); examples include the Mid Hill - Collin Top ridge. (Accidental fires have spread into this area in the past which serve to increase the dominance of heather.) There are also examples on the steeper slopes and summits of peat erosion, both with haggs - as on Mid Hill - and with gullies - e.g. on Crockraver.

Irish Red Data Book bird species associated with the blanket bog include breeding red grouse, golden plover, dunlin, merlin, and hen harrier. The site also supports a diversity of scarce insect species including the rare ground beetle Bembidion geniculatum, which is recorded for only one other location in Ireland.

Peat cutting is not presently a problem in this LCA, largely due to its inaccessibility. In the past, however, there was extensive cutting of peat near the Cranny Water, above Carnlough, for chemical extraction. This has healed, but has left a large area dominated by heather.

Wetlands and Lakes

Several types of upland and base poor lakes occur on the plateau. The most common lake types are characterised either by the association of yellow water-lily with white water-lily or by an association in which water lobelia is prominent. Loughnabrick and Natullig Lough have been classified as type 3 (Mesotrophic lakes) in the Northern Ireland Lake Survey, which are natural lakes, unenriched and characterised by Isoetes-Lobelia and rare in Northern Ireland. Loughnatrosk is a mid altitude lake which contains the rare opposite-leaved pondweed. The marginal lake vegetation around most of the lakes tends to be sparse, but around the three small lakes that comprise the Glenariff Lakes FNR, sedges are common, including the rare few flowered sedge. Mallard, teal and redshank use these lakes during the nesting season and tufted duck and pochard are present in winter.

Fens are small and scattered - see under 'flushed areas' above. Although there are many rivers rising in the plateau, there are no records of Priority Species; nevertheless several form the headwaters of salmonid 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: there are no issues relating to woodlands in this LCA

GRASSLAND AND ARABLE

Issue: there are no significant areas of farmland in the LCA

HEATH AND BOGS

Issue: potential damage to upland heathland and 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 afforestation

Issue: blanket bogs of national and international importance

Actions:

• maintain the integrity of existing blanket bog - in this area potential threats from accidental fires spreading into the area
• prevent further new forest planting on blanket bog

WETLANDS

Issue: maintain river water quality

Actions:

• present farming practices (extensive sheep grazing) should continue as these should not affect water quality
• forestry operations could lead to damage of water quality, particularly of sediment loads; operations, including planting and felling, need to be aware of their potential threat to water quality and wildlife.

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