Sheephaven Bay is a north-facing bay, situated on the north-west coast of Co. Donegal in north-west Ireland. The site occupies the entire inner part of the bay and includes the intertidal area at Carrickgart. The site's bedrock geology is quite varied, with schists (at least two types), quartzites, and metadolerites present. Several rivers, notably the Lackagh River, the Duntally River, the Faymore River and the Carrownamaddy River flow through the SAC. The site contains a diversity of habitats ranging from intertidal flats, mudflats and sand dunes, to lakes, rivers, heaths, scrublands and woodlands.
The site is a SAC selected for the following habitats and/or species from Annexes I/II of Directive 92/43/EEC (priority types are indicated with an asterisk, the area in hectares is shown in parentheses):
1140 Tidal Mudflats and Sandflats (765,7412)
1310 Salicornia Mud (21.5)
1330 Atlantic Salt Meadows (49.05055)
1410 Mediterranean Salt Meadows (17.25065)
2120 Marram Dunes (White Dunes)( 5.4639)
*2130 Fixed Dunes (Grey Dunes) (257.8871)
2190 Humid Dune Slacks (3,191)
*21A0 Machairs (55.26)
91A0 Old Oak Woodlands (4.0894)
1395 Petalwort (Petalophyllum ralfsii)
1065 Marsh Fritillary (Euphydryas aurinia)
Extensive areas of intertidal sands and muds occur in the Back Strand, Ards Strand, Doo Castle Strand, and at Carrickgart. Marble Hill Strand is a northeast-facing beach on the west side of the bay. The sediment here is fine, well-stratified sand, and the communities present are representative of shorelines moderately exposed to or protected from wave action.
The rare hermit crab Diogenes pugilator is present at its northernmost recorded locality in Ireland.
The site is particularly notable in a national context due to its highly vegetated intertidal zone. The Sand Flats support one of the largest areas in Ireland with annual vegetation dominated by Salicornia europaea and is the largest known area of habitat that is not affected by Spartina townsendii, an invasive species that threatens this habitat. There are also excellent examples of unmodified areas of pioneer vegetation and upper salt marsh communities. The site is undergoing active recovery and this is having a positive influence on the site.
Large areas of sand dunes are present at Rosapenna and Marble Hill. The white dunes are dominated by Ammophila arenaria, with abundant red fescue (Festuca rubra), and Geranium molle grasses and clover (Trifolium spp.) found on the fixed dunes behind. Some sand dune areas in Rosapenna have been damaged by agricultural improvements and golf course development has also had an impact on the site. Moist dune depressions are present in Rosapenna, both in the far south (Glenree / Magheramagorgan) in the larger area of unmodified dunes, as well as in the far north where there is an interesting co-existence of xerophytic dune grasslands, peat ecosystems, and dune vegetation. moist dune depressions.
A small intradune depression is present at Marble Hill, in the fixed dunes that slope down to the rear at Clonmass. The intradunar depression contains stagnant waters into which the waters that drain from the adjoining lands flow. The intradune depression is dominated by the typical species Carex nigra, Cola de Caballo spp. (Equisetum spp.), Hydrocotyle vulgaris, Mentha aquatic, Potentilla anserina and the moss Calliergonella cuspidata.
A relatively small area of Machairs lies on flat to gently rolling terrain behind the dune system, northwest of the village of Carrigart. Typical species such as red fescue, plantain (Plantago lanceolata), Lotus corniculatus and daisy (Bellis perennis) are present. The machair shows an interesting gradation to the vegetation of the marshes.
An extensive area of saltmarsh is found in the Back Strand, with additional areas in Ards Strand and to the west of the village of Carrigart. A variety of rushes (Carex spp., Juncus spp.), including Carex distans and Juncus maritimus, are found, along with Armeria maritima and Aster tripolium.
The site includes several areas of tree formations. Creeslough Wood is home to a variety of deciduous trees, including oak (Quercus sp.), holly (Ilex aquifolium), and hazel (Corylus avellana), but birch (Betula pubescens) is also a common tree. Ards Forest Park includes areas of deciduous forest and coniferous plantations. The rhododendron (Rhododendron ponticum) is widespread in parts of the woodland. Two rare species of Myxomycetes fungi have been recorded in Ards: Cribraria rufa and Stemonitopsis hyperopta.
A rare liverwort, Petalophyllum ralfsii, a species listed in Annex II of Directive 92/43/EEC, has been recorded on this site.
Euphydryas aurinia, a butterfly listed in Annex II of Directive 92/43/EEC and on the Red List, is known from its suitable habitat (machair and dunes with Succisa pratensis) in Ards and Carrigart and may be present elsewhere. The Ards habitats are home to a remarkable assemblage of butterflies, including one of the northernmost localities for Leptidea juvernica in Ireland. In total, 21 species are known, including the red-listed and near-threatened species Cupido minimu), Argynnis aglaja, Hipparchia semele, and Coenonympha pamphilus. The following red-listed Near Threatened terrestrial molluscs are also known from the SAC: Pupilla muscorum, Helicella itala, Leiostyla anglica, Vertigo antivertigo, Vertigo pygmaea, and Vertigo substriata.
Intertidal sand-mud flats support moderate numbers of waterfowl in fall and winter. These include Tadorna tadorna (75), Anas Penelope (414), Anas crecca (129), Anas platyrhynchos (117), Haematopus ostralegus (155), Charadrius hiaticula (48), Calidris alpina (107), and Numenius arquata (86) ( data from the period 1984 / 85-86 / 87). The site is sometimes used by the population of Branta leucopsis which is concentrated in New Lake (Dunfanaghy), with flocks numbering 300. Branta leucopsis is listed in Annex I of Directive 2009/147/EC. Other Annex I species associated with the site include choughs (Pyrrhocorax pyrrhocorax) (2 possible breeding pairs), the occasional visitor peregrine falcon (Falco peregrinus), and common tern (Sterna hirundo). Terns have not been recorded to breed in recent years, although suitable habitat exists. Part of the site is a wild bird sanctuary.
The site is of particular importance for conservation due to the presence of good examples of several habitats listed in Annex I of Directive 92/43/EEC and because of the important bird populations it hosts.