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Upper Lough Erne Biodiversity Profile

Last updated: 25 January 2010
 

In the following account it should be noted that for consistency, the biodiversity section follows a 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

Woodlands cover around 13% of the LCA, which is double the percentage for Northern Ireland as a whole (5.6%); broadleaved and mixed woodlands account for most of the woodland, which is also unusual for Northern Ireland. Both of these differences may be explained by the presence of large estates, in particular the Crom Castle estate, the large amount of wet woodland around the shores of Upper Lough Erne, and the high number of wooded islands. Coniferous forest is restricted to Naan Island, although here there are compartments of oak and of ash in addition to those of Sitka spruce, and plantations within the Crom estate.

The woodland at Crom Castle is of high scientific and conservation value. The ancient origin, degree of naturalness and extent of semi-natural woodland makes it one of the most important and largest blocks of mature broadleaved semi-natural woodland in Northern Ireland and in Ireland as a whole. The woods, wood pasture and parkland habitats (lowland woodland pasture and parkland) are important in an Irish contest for their epiphytic lichens and saproxylic (of dead wood) invertebrate communities.

picture of Parkland trees at Crom estateMost of the woodland at Crom (a National Trust property and also Crom ASSI) contains variable densities of mature oaks, which appear to have been planted for timber and landscape purposes on ancient woodland sites. Ash, sycamore, beech, lime, Scots pine and grand fir are amongst the range of trees that occur. Ancient woodland sites pre-date 1600 AD and are significant because they may contain species less common in more recent woods. Amongst the mature trees there is frequently dense growth of young trees, usually ash, but often with sycamore and others intermingled. Alder and willow can be found in poorly drained areas.

The Crom woodlands and parkland contain many vascular plants with a restricted distribution in the British Isles. In addition they are notable for mammals, particularly bats, and the wide variety of habitats gives rise to a range of bird species including snipe, heron and garden warbler. The invertebrate fauna is also of particular importance and the area is known to support many rare Irish species.

Several of the surrounding islands were also planted under the management of the Crom estate, for example, the Reilly & Gole Woods NNR. Reilly Wood has old oak trees planted some 150 years ago; they are evenly spaced with bilberry and wood sorrel beneath. Rhododendron, originally planted as shelter for game, encroached into the woodland but through careful management has now been removed, allowing heather and native trees, especially birch and holly, to grow. Gole Wood is recovering from felling during World War II; there are now many young oak, alder, birch, ash and willow trees. Inishfendra Wood, on an island to the southeast of the estate, is of dry oak wood and wet alder-ash.

In the north of the lough, many of the islands are wooded and typically with ash and oak, but here too there is evidence of planting with conifers and beech intermingled, especially on those islands offshore of the Belle Isle and Corrard House estates where the woodlands are of similar species.

Wet woodland is common around the shores of the lough, typically of alder carr with willow, and ash and birch in the drier parts. It is often associated with swamp and fen (see below). At Crom, almost all of the carr has developed in recent decades on the former lake bed and is not of high nature conservation interest. Birch woodland is found on some of the cut-over peat, but is not extensive.

Whereas most of the drumlins and low hills in the LCA are covered by surface water gleys (soils with impeded drainage) derived from calp till, in the northwest Knockninny Hill is an outcrop of limestone with thin, rocky soils. On the steeper slopes hazel scrub and upland mixed ashwood have developed. The calcicolous (favouring lime) herb layer is of moderate diversity, although the scrub and woodland is grazed, and supports a number of notable species such as columbine, stone bramble and includes the yellow bird's-nest, which is very rare in Northern Ireland.

Grassland and Arable

picture of a dense flowered orchid © Robert ThompsonAround 64% of the LCA, excluding open water, is in grassland and most of this has been classed as improved pasture. However, the degree of improvement varies from those fields that are intensively managed (and of low biodiversity), to those in which rushes have re-colonized (also generally of low biodiversity). Not only are the drumlin soils of poor internal drainage, but between them there are extensive flat, low-lying areas across which rivers and streams meander; maintaining productive pasture in these wet soils is difficult. In some parts, fields have not been intensively managed, indeed they have continued to be used for low intensity grazing and hay. Examples of such fields are located in the Belle Isle ASSI, Killymackan ASSI, Inishroosk ASSI, Trannish ASSI and Galloon ASSI among others; most have base-rich gleyed soils that give species-rich grasslands, often referred to as 'fen meadows' (purple moor grass and rush pastures). These not only have species that are locally and nationally rare, but are also habitats for rare invertebrates and important for breeding waders, including lapwing, snipe, redshank and curlew. These wet grasslands often merge into fens and with wet grasslands on the lakeshore.

Knockninny Hill ASSI, a limestone hill with predominantly thin soils, has dry grassland - upland calcareous grassland - characterised by a short, tightly grazed sward. A number of notable species have been recorded including a diverse orchid population. Dense flowered orchid is present, one of only two known Northern Ireland locations. A series of old meadows occur on the deeper, heavier clay soils around the lower slopes of the hill. The area is also important for butterflies and moths and several other notable invertebrates have been recorded.

In the more improved pastures, hedgerows often contain most of the biodiversity, as habitats for plants that enjoy the partial shade, for invertebrates, mammals and birds. In this LCA the hedges are generally well-maintained, although where the grasslands become less-productive the small fields tend to be surrounded by more overgrown and gappy hedges that may not have the varied habitats to give high biodiversity.

Despite the dominance in the farmland of land cover of generally low biodiversity, there is sufficient variation in the farmland (with woods, wet grasslands, fens, hedges) to provide habitats for several bird Priority Species - spotted flycatcher, song thrush, skylark, reed bunting and bullfinch have been recorded in the LCA.

Heaths and Bogs

Although peat is extensive around the lough shores and in the floodplains, especially in the east and south, lowland raised bogs are rare. Of those few remaining, all have been cut-over and are generally small. The largest area of bog is Monelegny Bog, but this is almost completely cut-over, has drains, and tracks through it that have facilitated recent mechanical extraction. Although the bogs do not have features of intact bogs that make them of high value to biodiversity, the presence of pools from cutting, banks of peat left by cutting, and colonization by trees does provide a diversity of habitats and species; for example, the pools provide habitats for dragonflies and the general bog surface is a habitat for wetland birds, including waders.

Wetlands and Lakes

Upper Lough Erne (Upper Lough Erne SAC, Upper Lough Erne SPA, Upper Lough Erne Ramsar) is an example of a northern or western eutrophic lake of glacial origin in Northern Ireland. The lake has a very long shoreline and numerous associated satellite lakes, many of which are included in the SAC. Aquatic vegetation is extensively developed; both club-rush - common reed, and reed canary-grass - shoreweed - spike-rush associations are well developed on the shore. There are transitions from open water to reedbeds and fen vegetation that can be seen around many of the islands and inlets of the loughs, including several of the ASSIs - for example, Corraslough Point ASSI, Killymackan Lough ASSI. There is transition to fen-meadows and other wet grasslands at many of these sites.

picture of a lunar hornet moth © Robert ThompsonThe Lough and its environs support several rare, vulnerable or endangered species or sub-species of plant and animal. Plant species in published or draft Irish Red Data Books include, fen violet, Irish lady's tresses orchid, pointed stonewort and the moss Fissidens monguillonii. Vertebrate species in the Irish Vertebrate Red Data Book include whiskered bat, shoveler, pochard and brook lamprey. Rare or vulnerable invertebrate species include white-clawed crayfish, lunar hornet moth, a pondskater Limnoporus rufoscutellatus, the water beetles, Donacia aquatica, Donacia bicolora, Gyrinus distinctus, Gyrinus natator and Hydroporus glabriusculus and the carabid Lebia cruxminor.

Upper Lough Erne qualifies as an SPA by regularly supporting internationally important numbers of wintering whooper swan. It provides a core protected area in Northern Ireland, there being interchange between the swans using the protected area and those ranging more widely on surrounding farmland. Upper Lough Erne also supports regionally important numbers of the Greenland white-fronted goose and an important assemblage of breeding birds that includes common tern. Other migratory breeding birds present include great crested grebe and important concentrations of three species of waders, which are declining elsewhere, curlew, snipe and redshank (see grasslands and bogs above).

Northern Ireland holds one of the strongest populations of the otter in the UK and Upper Lough Erne holds a dense and large population.

Several of the lakes are included within the designated areas above, but the LCA has a wealth of lakes. The Northern Ireland Lake Survey classified some as of low or no priority for conservation because the nutrient status has been increased through input of water from agricultural land that has had applications of fertilizers and slurry. The majority of lakes classified were eutrophic standing water - Northern Ireland has a large proportion of the UK resource - including some of the Nuphar/Elodea/Hydrocharis type that is confined to the southern Erne system. Frogbit is a local species found in three main areas: Lough Erne, the southeast of Lough Neagh and the southern end of the Ards Peninsula. A few lakes were classed as marl lakes, including Lough Garrow that belongs to the type (Nuphar/Elodea/Hippuris) that is the cleanest, clearest, hard water lake type with the highest base status and most specialised flora.

The Cladagh (Cladagh (Swanlinbar) River ASSI) rises high on Cuilcagh Mountain, flowing steeply downslope before widening as it enters Upper Lough Erne. Trees line the lower half of the river where it is slow-flowing, deep and eutrophic and the plants are typical of waters rich in nutrients. Vascular plants are dominant and include stands of broad-leaved pondweed and yellow water-lily. The Cladagh (Swanlinbar) and the Colebrooke Rivers have river water crowfoot, but their location is not specific and may be outside the LCA.

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: high woodland cover with high biodiversity of both habitats and species

Actions:

GRASSLAND AND ARABLE

Issue: poor biodiversity of improved farmland, but significant wet and species-rich grasslands

Actions:

HEATH AND BOGS

Issue: no intact raised bogs, but cut-over offer habitats for wetland birds, invertebrates

Actions:

WETLANDS

Issue: fens in Northern Ireland are a large proportion of the UK resource, Lower Lough Erne has a significant part of this resource

Actions:

Issue: internationally important lakes and rivers - significant not only for their flora (very rare eutrophic and marl lakes), but also for their fauna, including wetland birds

Actions:

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