|IPA Factsheet - Strangford Lough|
Site Description Strangford Lough is one of the largest sea Loughs in Northern Ireland. The sea inlet is made up of a drowned drumlin field, with raised beach terraces shaped by Quaternary glaciation. The drumlins display stages of wave erosion, with a number reduced to rocky islands or 'pladdies'. The Lough is a Earth Science Conservation Review Site (ESCR) because of its coastal processes (contemporary processes at Bar Hall Bay, Gransha Point, Youran, Narrows, Dorn and Northern Mudflats). There are 120 islands within the Lough and 150 miles of coastline. Intertidal deposits cover some 50km2 and the diversity of marine habitats is internationally renowned. Ten intertidal habitats have been identified on the basis of substrate and wave exposure, each having a characteristic range of species. No comparable area has so wide a range of species or habitats in Northern Ireland. The site is also the most important Irish breeding location for the common seal. There are a number of species of interest because they are near the northern or southern extremes of their ranges. The richness of the marine flora and fauna can largely be attributed to physiographical features resulting in the immense tidal flow through The Narrows, the range and timing of the tidal variations in the Lough and the wide variety of substrates which occur. Apart from the intertidal communities the site has adjoining habitats which include transitions from salt to freshwater and habitat mosaics. In addition the shoreline habitat incorporates vast areas of mud flats. Of particular note in the Lough are internationally and nationally important populations of waders and wintering waterfowl. (North Ireland Environment Agency)
Botanical Significance Noted for marine algae interest. The Strangford Lough includes extensive mudflats and also sandflats, saltmarsh and rocky intertidal habitat. The mudflats support luxuriant beds of eelgrass: Zostera noltii, Zostera angustifolia, Zostera marina and Ruppia maritima are all present, with the latter widespread but quite local in its distribution. Such extensive beds, are rare in the British Isles. Biological interest is associated with the intertidal communities and the unusual juxtaposition of habitats, ranging from splash zone, saltmarsh and strandline vegetation, to actively developing foredune, species-rich calcareous dune grassland, maritime grassland and maritime heath. This has resulted in a diverse range of plant communities. This site is an exeptionally rich littoral community, with species of both sheltered and exposed shores. It’s the second most diverse rocky shore known in Northern Ireland, and is particularly rich in seaweeds, or marine algae. Over 90 species of Green, Red and Brown algae have benn recorded. The upper shore is dominated by the lichen Verrucaria maura. Channelled Wrack Pelvetia canaliculata grades downshore into Spiral Wrack Fucus spiralis, and there are successive bands of Knotted Wrack Ascophyllum nodosum, Batters Frond Gigartina stellata and Oarweed Laminaria digitata towards low tide. The rocks have an extensive splash zone with a well-developed zonation of characteristic maritime lichens. Saltmarsh is developed in sheltered bays. The saltmarsh consists of a matriz of Sea-milkwort Glaux maritima, Common Saltmarsh-grass Puccinellia maritime, tall clumps of Red Fescue Festuca rubra and Saltmarsh-grass Puccinellia maritiam, tall clumps of Red Fescue Festuca rubra and Saltmarsh Rush Juncus gerardii, and occasionally Sea Plantain Plantago maritime, Sea Rush Juncus maritimus and Common Couch Elytrigia repens. Smaill stands of beach-head saltmarsh are present. These are dominated by sedhes, such as Distant Sedge Carex distans, Long-bracted Sedge C. extensa and Saltmarsh Flat-sedge Blysmus rufus, and spike-rushes, suchs as Few-flowered Spike-rush Eleocharis quinqueflora and Slender Spike-rush Eleocharis uniqlumis. Coast is well endowed with strandline vegetation, generally dominated by Sea Mayweed Tripleurospermum maritimum and Cleavers Galium aparine. The dunes along the shore have a narrow foredune formed by tussocky Marram Ammophila arenaria and small amounts of Sand Couch Elytrigia junce. The bacj of the foredunes is covered by a rather open grassland, dominate by Marram Ammophila arenaria and Red Fescue Festuca rubra, wich gradually becomes more species-rich and includes such plants as Lady’s Bedstraw Galium verum and Field Wood-rush Luzula campestris. This is interspersed with areas in wich Red Fescue Festuca rubra, Yorkshire Fog Holeus lanatus and Yarrow Achillea millefolium are the dominant species. The dry areas are dominated by fine grasses and Wild Thyme Thymus polytrichus. Common Bird’s foot trefoil Lotus Corniculatus, Common Whitlowgrass Erophila verna, Marram Ammophila arenaria, Common Centuary Centaurium erythraea, the moss Torula ruralis and the lichen Cladonia portentosa. This dry grassland extends up onto the coastal plateau, where increasing frequencies of Downy oat-grass Helictotrichon pubeacens and Quaking-grass Briza media are found. The bryophyte cover is dominated by Rythydiadelphus trigetrus and Pseudoscleropodium purum. (North Ireland Environment Agency)
General Habitat Description Strangord Lough is on of the largest sea-loughs in Northern Ireland, and possesses a landscape of drowned drumlins and raised beach terraceswich have been shaped by the Quaternary glaciation. The drumlins display various stages of wave erosion, with a number of them reduced to rocky islets and reefs, know locally as “pladdies”. The intertidal zone covers approximately 50km2 and the diversity of the marine habitats is internationally renowned. The many different intertidal habitats are identifiable on the basis of substrate type and wave exposure with each one supporting a characteristic range of species; no comparable area in Northern Ireland has so wide range of either habitats or species. The richness of the marine flora can largely be attributed to physiographical features resulting in the inmense tidal flow through The Narrows, the range and timing of the tidal variations in the Lough and the wide variety of substrates wich occur. The Lough as a whole represents a unique and extremely complex, integrated system.
Conservation Issues Mudflats: • Discourage disposal of dredge or other material • Encourage sympathetic use of the habitat to ensure that disturbance and physical damage to the intertidal habitats and communities are minimised • Minimise the removal of species through unregulated bait digging and shellfish gathering wich can lead to damage to, or a loss of, communities and habitat. • Management should aim to maintain good water and sediment quality whilst the sediment budget within the estuarine or coastal system should no be restricted by anthropogenic influences Seagrass beds (Zoostera): • Maintain good water and sediment quality, as seegrass beds are sensitive to excessive nutrient enrichment wich can lead outbreaks of the ephemeral algae Enteromorpha that can subsequentlu smother the seagrass • Encourage the sympathetic use of the habitat to ensure that disturbance and physical damage to the seagrass is minimised. • Ensure that the sediment budget within the estuarine or coastal system is not restricted by anthropogenic influences. Construction, such as causeways and seawalls, can alter the sedimentary regime wich may in turn impact seagrass beds as they are sensitive to such changes Coastal saltmarsh: • On sites where have traditionally been grazed, encourage the continuation of this practice. Overgrazing should be avoided as it may result in a reduction in species diversity and cause poaching. • Encourage management wich favours the natural processes of sediment movement and the dynamics of saltmarsh succession. • Maintain the diversity and quality of the saltmarsh by ensuring that there is no application of fertiliser, slurry or herbicide. Intertidal rock: • Encourage the maintenance of goo water quality through the contrl of polluton as this may affect reef communities, particularly due to increased turbidity (wich may reduce algal communities) or siltation (wich may smother animal communities). • Discourage the unregulated removal of species through bait digging, shellfish gathering and seaweed harvesting wich can lead to damage to, or loss of, coastal communities and habitat • Encourage management wich favours the natural processes of sediment movement. • Encourage sustainable fishing practices and, where appropriate, the development of non disturbance zones. (North Ireland Environment Agency)