Eastern Mournes ASSI

Protected area type: Areas of Special Scientific Interest
Feature type: 
  • Species
  • Earth Science
  • Down
Council: Newry, Mourne and Down
Guidance and literature: Eastern Mournes ASSI

The area is of special scientific interest because of its geological and physiographical features, its heathland and upland flora and fauna. The Mourne Mountains consists of a compact range of mountains forming the highest ground in Northern Ireland with twelve summits extending over 600m and Slieve Donard rising to 852m. The Mourne Mountains are significant as they are the largest outcrop of tertiary granites and associated series in the British Isles, covering some 150 km2 and contains classic features of upland glaciation. The area supports the most extensive heathland in Northern Ireland.

Biological interest of the site relates to the size, quality and diversity of the habitats within the area and the presence of particular plant and animal species. The area supports extensive tracts of heather, which is a scarce and scattered resource in Northern Ireland. The dwarf shrub communities are highly variable, reflecting a range of environmental conditions, supporting an array of associated flora and fauna. Blanket bog and grassland communities are also well represented, producing a varied and diverse range of habitats. This diverse range of habitats exhibits a well defined altitudinal sequence. A number of rare plants including bryophytes are associated with these habitats.

Below the level of 250m, along the Eastern coastal margins of the area, the heath is often characterised by the abundance of Western gorse. This type of vegetation is generally restricted to the warm, oceanic regions of lowland Britain, and its extensive occurrence so far north is notable. This vegetation gives way up slope to vegetation in which heather and bell heather are the dominant species, forming the most widespread heath community in the Mournes.

At higher altitudes, transitional communities, containing species such as bilberry and crowberry, are occasionally present, although these are generally restricted to the cooler shaded slopes. More commonly, the dwarf-shrub heaths pass directly into montane summit heaths, often dominated by grasses such as sheep's-fescue and the bents Agrostis spp, with the moss Racomitrium lanuginosum. Bryophryte-dominated Racomitrium heath is present on the highest north facing scree slopes. This is a scarce vegetation type in Northern Ireland and is generally confined to the north of the British Isles.

On the lower north facing slopes, the damp microclimate allows wet heaths to develop. This community is characterised by the prominence of cross-leaved heath and is noted for the abundance of the rare northern Atlantic moss Campylopus setifolius.

There are a number of upland lakes and reservoirs in the area. These include Binnian Lough and Blue Lough which are categorised by the rare association of quilwort and water lobelia indicative of oligotrophic waters.(a body of water deficient in nutrients for supporting plant life)

In addition to those plants already mentioned, a number of rare and notable plants have been recorded in the area. These include Irish lady's tresses, parsley fern, beech fern, Alpine clubmoss and stiff sedge. Rare bryophytes also found include mosses Rhabdoweissia crenulata and Glyphomitrium daviesii, and the liverworts Bazzania tricrenata, Lepidozia pearsonii, Harpalejeunea ovata and Sphenolobsis pearsonii.

Notable breeding bird species in the area include; red grouse and a few ring ouzel. High cliffs with ledges hold breeding peregrine falcons and ravens.

The heathlands of the Mournes support a variety of invertebrate communities. Individual species include the heteropteran Alydus calcaratus at its only Irish site. The summit heaths support one of the largest assemblages of specialist montane invertebrates so far recorded in Ireland. Species of note include the predatory ground beetles Notiophilus aesthuans and Miscodera arctica and the dwarf willow-feeding Sawfly (Pontania crassipes). The summit of Slieve Donard is the only known Irish site for these three species. 

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