Annex 3 – DfI_9782_61981_Omagh Bio Audit
A5WTC-2019-TR-019 DfI Roads Theme Rpt_Priority Habitats v1.0 Annex 3 – DfI_9782_61981_Omagh Bio Audit
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A5WTC-2019-TR-019 DfI Roads Theme Rpt_Priority Habitats v1.0
Biodiversity Audit of Omagh district
Omagh Local Biodiversity Action Plan
Contents
Page No. Habitat Audit – Introduction 3
1. Bogs 6 a. Lowland raised bog 7 b. Blanket bog 10 2. Boundary and linear features 13 a. Ancient and/or species rich hedgerows 14 3. Broadleaved, mixed and yew woodland 16 a. Parkland 17 b. Mixed ashwoods 19 c. Oakwood 21 d. Wet woodland 24 4. Dwarf shrub heath 26 a. Upland heathland 27 5. Fen, marsh and swamp 30 a. Fens 31 b. Purple moor-grass and rush pasture 33 c. Reedbeds 35 6. Improved grassland 37 a. Coastal and floodplain grazing marsh 38 7. Neutral grassland 40 a. Lowland meadows 41 8. Standing open water and canals 43 a. Eutrophic standing waters 44 b. Mesotrophic lakes 47
Species Audit – Introduction 49
Priority Species 51 Species of Conservation Concern 71
Locally Important Habitats and Species 76
References and Bibliography 81
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Habitat Audit - Introduction
In order to produce a Biodiversity Action Plan that aims to conserve and enhance the existing biodiversity of Omagh, a biodiversity audit first needs to be carried out to identify what important habitats and species occur in the Omagh district.
A habitat is where a plant or animal lives, providing them with food, shelter and protection. 44 priority habitats were identified in the document, ‘Biodiversity: the UK Steering Group Report – Volume 2: Action Plans’, as those that merited extra conservation action. These priority habitats were selected using one or more of the criteria outlined below.
Selection criteria for United Kingdom (UK) Priority habitats:
Habitats for which the UK has international obligations.
Habitats at risk, such as those with a high rate of decline, especially over the last 20 years.
Habitats which are rare.
Habitats which possess critical roles in supporting mobile or key species.
Of the 44 priority habitats identified using this criteria, 37 are found in Northern Ireland. These 37 UK priority habitats were automatically adopted as Northern Ireland priority habitats. However, in order to select additional priority habitats, three criteria were adopted and any habitat satisfying at least one of these three criteria qualifies as a Northern Ireland priority habitat as outlined below.
Selection criteria for Northern Ireland (NI) priority habitats:
Habitats at risk in NI or Republic of Ireland (RoI) generally, because of either rarity or a high rate of decline.
Habitats for which NI has a large part of either the UK or Island of Ireland (IoI) total (10% of UK or 50% of IoI)
Habitats of particular importance for priority species
Applying these criteria led to the selection of three additional priority habitats in NI; Marl lakes, crowfoot rivers and montane heaths. The ‘Biodiversity in Northern Ireland: Recommendations to Government for a Biodiversity Strategy’ document
3 lists the 40 priority habitats and their associated broad habitat types, which are present in NI. Table 1 lists the NI broad and priority habitat types and indicates which priority habitats occur in Omagh District. Of the 40 NI priority habitats, 15 occur in the Omagh District.
Table 1: Northern Ireland Priority Habitats occurring in Omagh District
BROAD HABITAT PRIORITY HABITAT PRESENCE IN OMAGH DISTRICT Acid Grasslands Lowland dry acid grassland Arable and Horticulture Cereal field margins Bogs Lowland raised bog * Blanket bog * Boundary and linear Ancient and/or species-rich * features hedgerows Bracken Broadleaved, mixed and Parkland * yew woodland Mixed ashwoods * Oakwood * Wet woodland * Built up areas and gardens Calcareous grassland Calcareous grassland Coniferous woodland Continential shelf slope Dwarf shrub heath Lowland heathland Upland heathland * Fen, marsh and swamp Fens * Purple moor-grass and * rush pasture Reedbeds * Improved grassland Coastal and floodplain * grazing marsh Inland rock Limestone pavement Inshore sublittoral rock Littoral and sublittoral chalk Modiolus beds Sabellaria spinulosa reefs Tidal rapids Inshore sublitoral sediment Maerl beds Mud habitats in deep water Saline lagoons Seagrass beds
4 Sublittoral sands and gravels Littoral rock Littoral and sublittoral chalk Sabellaria alveolata reefs Littoral sediment Coastal saltmarsh Mudflats Seagrass Sheltered muddy gravels Montane habitats Montane heath Neutral grassland Lowland meadows * Offshore shelfrock Offshore shelf sediment Rivers and streams Crowfoot rivers Standing open water and Aquifer fed naturally canals fluctuating water bodies Eutrophic standing waters * Mesotrophic lakes * Marl lakes Supralittoral rock Maritime cliff and slopes Supralittoral sediment Coastal sand dunes Coastal vegetated shingle Urban
Broad habitats:
The broad habitat types comprehensively cover, and should encompass all the habitat types that occur in NI.
Priority habitats:
Priority habitats form a selected list of habitats defined as being of the highest conservation concern on the basis of expert judgement.
Data availability and limitations
Current extent, status and distribution: This section outlines the extent and distribution of the habitat within the district and set within the NI context, based on the most up to date available data. Where possible, the current status of the habitat is indicated.
Significance for species:
5 This section discusses the importance of the priority habitat for local species and where possible priority species is outlined.
1. Broad Habitat: Bogs
The cool, wet climate of Island of Ireland (IoI) is ideal for producing peat, so peatlands form a characteristic part of the Irish landscape (EHS, 2004) Peatlands or bogs are found where peat has accumulated to form a deep layer. There are three types of peatlands in NI; lowland raised bog, blanket bog and fens. The main difference between these is that lowland raised bog and blanket bog receive nutrients only through precipitation (ombrotrophic) whereas fens receive nutrients via precipitation and groundwater (minerotrophic). Lowland raised bog and blanket bog are identified as priority habitats in NI as explained further below. Fens are explored under the broad habitat of fen, marsh and swamp.
NI contains a significant proportion of the remaining bog resource in Europe and therefore the importance of these bogs cannot be over-emphasised. Across Europe, bogs have been destroyed or changed significantly through drainage, reclamation and peat-cutting (EHS, 2004). The Northern Ireland Countryside Survey (NICS) monitored changes in land cover from 1991 to 1998. It estimated that there was an overall decline of wet bog in NI by 21%. Within the Sperrin Area of Outstanding Natural Beauty (AONB) lowlands area, there was a 9% decline, which can be used as a representative pattern of decline for the Omagh district area (Cooper and McCann, 2002 and Cooper et al, 2002)
Due to the sensitive nature of bogs and their recent rates of decline, many bogs have been designated as parts of Ramsar sites, Special Areas of Conservation (SAC) and Areas of Special Scientific Interest (ASSI) (Such areas in Omagh include Fairy Water Bogs and Black Bog, both Ramsar sites, SAC’s and ASSI’s. Other SAC’s include Deroran Bog, Cranny Bogs, Tully Bog and Tonnagh Beg Bog, which are also ASSI’s). Although these sites are protected under legislation, they represent only a small proportion of bogs within Omagh. Therefore, it is important that as priority habitats, the associated habitat action plan that aims to conserve the overall distribution of bog currently in favourable condition is carried out.
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Priority Habitat 1a: Lowland raised bog
Summary Table:
Priority Habitat Lowland raised bog Extent and Distribution Area present 690.46 Ha * Main locations Fairy Water Valley Omagh farmland Patches of the Murrins Associated Priority Wet woodland Habitats Fen Purple moorgrass and rush pasture Associated Priority Curlew Species Red grouse Grasshopper warbler Irish hare Main threats/local Peat cutting issues/comments Drainage Agricultural improvement Inappropriate grazing regimes Scrub encroachment * estimated figure calculated from area of lowland raised bog within Forest Service Northern Ireland landholdings and area of lowland raised bog entered into the 2005/2006 Countryside Management Scheme, DARD, therefore not a total figure.
What is lowland raised bog?
Lowland raised bogs are peatland ecosystems that are found in lowland areas generally below 150m. In NI they are typically found in wide river valleys or between glacial hilly drumlins. The waterlogged soils here provide the ideal anaerobic conditions required for the accumulation of dead organic matter and the formation of peat. Their name is derived from the classic dome shape that forms as the bog develops and they can often reach over 12 metres in depth (EHS, 2003).
Similar to blanket bogs, the surface of an intact lowland raised bog is waterlogged, acidic and deficient in nutrients. Therefore, only a limited number of specialised plants can tolerate these harsh conditions such as cotton grasses, bog asphodel, cross leaved heath, sundews, bilberry and the increasingly scarcer cranberry. The main building block of peat is bog mosses. These mosses hold water like a sponge contributing to the waterlogged, acidic conditions (EHS, 2003).
7 Lowland raised bogs often form mosaics of pools, hummocks and lawns. They also form larger mosaics with adjacent habitats of purple moor grass and rush pasture and wet woodland, both priority habitats. Current extent, status and distribution
Since the 1800’s there has been a dramatic decline in the extent of lowland raised bog in NI and across the rest of north-west Europe. It is estimated that NI has lost 92% of its undisturbed lowland raised bog falling from 25000 ha to 2000 ha (EHS, 2003). The Northern Ireland Peatland Survey (NIPS) carried out by Queen’s University of Belfast (Cruishank & Tomlinson) commissioned by Environment and Heritage Service (EHS) in 1988 assessed the distribution and condition of NI bogs. It estimated that only 9% of the original lowland raised bogs were still intact. More recently, the NICS (Cooper, McCann & Meharg, 2002) which aimed to monitor land use change, shows a significant decrease of 8% in wet bog vegetation in the lowlands (<150m) between 1992 and 1998.
Within the Omagh area, lowland raised bogs are relatively widespread, found in most of the landscape character areas. Naturally, they develop along low-lying river valleys (Fairy Water Bogs Ramsar, SAC and ASSI) and in inter-drumlin hollows (Cranny Bogs SAC/ASSI and Tully Bog SAC/ASSI). They can also develop from old loughs or fens.
Cruishank and Tomlinson surveyed the mid-Tyrone area in 1988 as part of the NIPS. They described the area as having “hills that are not generally high, nor lowlands below 100m and slopes are rarely steep”. Due to the westerly location and higher rainfall, peatland is extensive in both uplands and lowlands. Therefore, the defining boundary between blanket bog and lowland raised bog is sometimes difficult (Cruishank & Tomlinson, 1988). These examples shown represent the best quality lowland raised bogs identified by survey and designated accordingly in Omagh. However, there are many more examples throughout Omagh that are in less favourable condition, but are still significant and provide valuable habitats for many local species. Such areas identified locally west of Dromore and Donaghanie, where cut over raised bog areas have been left to regenerate and are now dominated by mature heather, mosses and vascular plants such as bilberry and cross-leaved heath. The DARD Environmentally Sensitive Area/Countryside Management Scheme 2005/2006 figures show that 672.46 Ha of lowland raised bog within the Omagh district is under an agri-environment scheme and being managed for lowland raised bog conservation. Although this figure represents only the land owned by farmers in the scheme, it gives an indication of the extent of lowland raised bog in Omagh.
Significance for species
8 A limited range of specialist plant species occur on this habitat type due to the acidic, waterlogged and low nutrient conditions which prevail. Bog mosses are the keystone species and these give a bog its characteristic spongy surface. Vascular plants such as heather, cross-leaved heath, bilberry, bog asphodel and cotton-grasses are common. Other higher plants such as bog sedge and long- leaved sundew are rarer. The rare purple liverwort, which is restricted to the western bogs, is found in some lowland raised bogs in Omagh including Cranny Bogs (EHS, 1997) and Deroran Bog (EHS, 1994).
Invertebrates found in lowland raised bogs include many species of dragonflies and damselflies, where bog pools occur, butterflies such as the large heath and many micro-moths. Birds typical of lowland raised bog and of Omagh include snipe and grasshopper warbler, found in the Fairy Water Bogs.
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Priority Habitat 1b: Blanket bog
Summary Table:
Priority Habitat Blanket Bog Extent and Distribution Area present 1594.55 Ha* Main locations South Sperrins Brougher Mountain, Mullaghcarn Lough Bradan The Murrins Black Bog Associated Priority Upland heathland Habitats Fen Purple moorgrass and rush pasture Associated Priority Curlew Species Red grouse Hen harrier Skylark Irish hare Main threats/local Peat cutting issues/comments Drainage Agricultural improvement Inappropriate grazing regimes Windfarm developments * estimated figure calculated from area of blanket bog within Forest Service Northern Ireland landholdings and area of blanket bog entered into the 2005/2006 Countryside Management Scheme, DARD, therefore not a total figure.
What is blanket bog?
Blanket bog generally occurs in higher altitudes of around 200m or more and is a layer of peat and associated vegetation of an average depth of 0.5 – 3m covering the land like a ‘blanket’. It is globally restricted to cool, wet climates like UK and RoI and is one of the most extensive semi-natural habitats in NI due to the high annual rainfall, topography and glacial soils. It builds up slowly as the vegetation dies back and decomposes, accumulating to form peat under waterlogged conditions. However, it can also form on steeper slopes where drainage is freer (EHS, 2003). Similar to lowland raised bogs, the surface of an intact blanket bog is waterlogged, acidic and deficient in plant nutrients. There are only a limited number of plants that can tolerate these harsh conditions growing on blanket
10 bogs. The main building block of peat is bog mosses. These mosses hold water like a sponge contributing to the waterlogged, acidic conditions. Other associated bog plant species include heather, cottongrasses, deergrass and liverworts, with the latter more typical of western bogs. It is worth noting here that blanket bogs and other similar habitats such as wet upland heath and purple moorgrass and rush pasture, often form mosaics over the landscape and the boundaries between the habitats is difficult to distinguish.
Current status, extent and distribution
There are relatively few sources of information useful for documenting the status, extent and distribution of blanket bog in the Omagh area but there is general information for NI. The Blanket Bog Northern Ireland Habitat Action Plan (HAP) summarises that the most extensive tracts of blanket bog tend to occur at altitudes in excess of 200m and are concentrated on the Antrim Plateau, the Sperrin Mountains and in County Fermanagh (EHS, 2003). The Sperrin AONB extends south into the northern part of Omagh district, however using other sources, blanket bog can be found in the lower lying lands to the west and south of Omagh town. As the rainfall in the north and west of NI is higher, there are more occurrences of blanket bog below the normal altitude of 200m with some as low as 90m (EHS, 2003).
The mid-Tyrone survey area in 1988 as part of the NIPS was described as having “hills that are not generally high, nor lowlands below 100m and slopes are rarely steep”. Due to the westerly location and higher rainfall, peatland is extensive in both uplands and lowlands. Therefore the defining boundary between blanket bog and lowland raised bog is sometimes difficult (Cruishank & Tomlinson, 1988).
Within the Omagh district blanket bog is found mainly on the higher slopes within the landscape character areas of Carrickmore Hills, South Sperrin, Bessy Bell and Gortin, Slievemore, Brougher Mountain and Lough Bradan. As highlighted in the summary table, blanket bog and heathlands often form a complex mosaic of landscapes. An example of this is the Murrins Nature Reserve, known locally as the Seven Sisters, which is a glacial complex that supports “rich heath vegetation”. As described by EHS, the area is comprised of dry ridges, bogland and kettle-hole lakes (EHS, 2006). The DARD Environmentally Sensitive Area/Countryside Management Scheme 2005/2006 figures show that 1412.55 Ha of heather moorland blanket bog within the Omagh district is under an agri- environment scheme and being managed for blanket bog conservation. Although this figure represents only the land owned by farmers in the scheme, it gives an indication of the extent of blanket bog in Omagh. However there has been an increase in area being managed for conservation from 2004/2005 to 2005/2006, rising dramatically from 46.99 Ha to 1412.55 Ha.
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On the whole, blanket bog in the area has suffered from peat cutting, drainage and overgrazing in the last few decades. Quite large areas of bog are described as in unfavourable condition due to these factors. However, a recent survey has shown there still remains some excellent examples of blanket bog habitat, aside from those already protected e.g. on Slievedivena an extensive area of cut-over blanket bog is regenerating well with over 80% heather cover. Other areas of important blanket bog were identified at Bessy Bell, Creggan and Tappaghan Mountain (EHS, 2006).
Significance for species.
A limited range of specialist plant species occur on this habitat type due to the acidic, waterlogged and low nutrient conditions which prevail. Bog mosses are the keystone species and these give a bog its characteristically spongy surface. Again heather, cross-leaved heath, bilberry, cotton-grasses and sedges are common in blanket bogs with cranberry and crowberry much rarer. Blanket bogs provide both breeding habitats for birds such as red grouse and skylark and feeding grounds for buzzards, peregrine falcons and more recently the golden eagle which was reintroduced to the RoI at Glenveagh National Park, Co. Donegal in 2000. The key mammal priority species found in Omagh’s blanket bogs is the Irish hare.
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Broad Habitat 2: Boundary and linear features
Boundary and linear features such as hedges, banks and ditches are characteristic of the traditional NI farming landscape (NIBG, 2000). They are important for biodiversity as provide a habitat in sometimes a rather sterile farmland setting or act as wildlife corridors between woodland pockets and other semi-natural habitats. Hedgerows are important, as they resemble woodlands in their species assemblage and structure. In NI, species rich or ancient hedgerows are a priority habitat.
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Priority Habitat 2a: Ancient and/or species rich hedgerows
Summary table
Priority Type Ancient and/or species rich hedgerows Extent & Area present Has not been surveyed or quantified Distribution Main locations Found locally adjacent to semi-natural habitats and low intensity farmland Associated Priority Lowland meadow Habitats Purple moor grass and rush pasture Mixed ashwoods Oakwood Wet woodland Parkland Associated Priority Irish hare Species All bat species Bullfinch Song thrush Barn owl Main threats/Local Historical farming practice –removal of hedgerows to Issues/Comments increase field size Neglect Over-cutting Lack or tree replacement Nutrient enrichment caused diversity reduction Removal due to many factors including development
What are ancient and/or species rich hedgerows?
Hedges are defined as linear boundaries, comprised of planted shrubs (Murray et al, 1992). The UK HAP defines species-rich hedgerows as those which contain five or more native woody species on average in a 30 metre length, however in NI they are taken as those that have six or more woody species. If a hedge has fewer than six woody species but a rich basal flora of herbaceous plants such as primrose, wood anemone, common dog-violet, bluebell, herb-robert etc, they are still classified as species rich (EHS, 2003).
Current extent, status and distribution
NI has the highest density of field boundaries in the UK with an average of 17km per km2 (Cooper et al, 2002) totalling to approximately 119,000km of hedgerows.
14 The NICS 2000 gathered a large amount of information on hedgerows. It is estimated that 37% (44,000 km) of NI hedges are species-rich. The condition of hedgerows within NI is recorded by the amount of species-rich hedgerows, however each length needs to be assessed on its own value for wildlife by surveying the shape and structure as well as the richness of the associated ground flora (EHS, 2003). Although most hedgerows will not qualify as ‘species-rich’, they still hold a very important resource for local wildlife and should not be discounted.
Species-rich hedgerows tend to occur adjacent to less intensively managed farmland in low-lying areas. These hedges tend to be tall, wide, unmanaged, and are concentrated in Co. Fermanagh. However, where the conditions are right in the Omagh district, species-rich hedgerows may occur. In NI, unmanaged, dense hedges (with less than 10% gaps) are the most species-rich. However, if left unmanaged, hedgerows can become ‘gappy’ and loose their biodiversity value (EHS, 2003).
Significance for species
Hedgerows are rich habitats for wildlife, including vascular plants, birds, mammals and insects. For birds, they provide valuable nesting habitats, shelter, berries and song posts. The structure of hedgerows is important as various birds prefer different structures. Most birds prefer tall hedges with many trees, although the dunnock and willow warbler prefer fewer trees. The linnet prefers shorter hedges with fewer trees.
Mammals in NI that rely on hedgerows for habitat, shelter or as a wildlife corridor from one habitat to another include woodmice, foxes, badgers, rabbits, hedgehogs, Irish hares and bats. Bats in particular rely on hedgerows for flight lines from freshwater bodies to wooded areas whilst feeding at dusk.
Many butterflies are associated with hedgerows as their food plants often grow in the herbaceous layer including the peacock and small tortoiseshell butterfly that rely on nettles to host their larvae.
Of the current NI priority species associated with hedgerows the linnet, barn owl, Irish hare, red squirrel and many bat species occur in Omagh.
15 Broad Habitat 3: Broadleaved, mixed and yew woodland
After the last ice age approximately 10,000 years ago, forests, first of birch, Scot’s pine and hazel, then of oak and ash, began to cover most lowland areas of the IoI. However, as humans have settled over the years, they have cleared these woods for harvesting and to create farmland. Consequently, there is now only 6% of woodland in NI, well below the European Union average of 31% (NIBG, 2000).
Woodland is the climax vegetation of IoI meaning that if all habitats were left to progress with no interference from man, some form of woodland would develop. There is a wide range of woodland types, all dependant on location, geology and climatic conditions. However, these can be broadly split into two types; coniferous woodlands and broadleaved/mixed woodlands. Coniferous woodlands in NI are predominantly conifer plantations of sitka spruce, Norway spruce and lodgepole pine, which are not native to UK and RoI. These were mainly planted in upland areas, as they were well suited to the mild, wet climate. Although they have commercial value, they support little biodiversity due to their simple woodland structure and because they are not native. However, they do have value for the native red squirrel, which in recent years has become more dependant on coniferous forests (NIBG, 2000).
Broadleaved/mixed woodlands include both woodlands that have been planted and semi-natural woodlands. These are of highest importance for a number of species, from birds and mammals through to the less conspicuous inhabitants of invertebrates, mosses, lichens and fungi. All of these species play an integral part in woodland ecosystems. As the wood matures, the biodiversity increases as the structure becomes more complex (NIBG, 2000). Within the category, four priority habitats occur both in NI and within the Omagh district; parkland, mixed ashwoods, oak woods and wet woodland.
16 Priority Habitat 3a: Parkland
Summary table
Priority Type Parkland Extent & Distribution Area Present 23.28 Ha Main Locations Beltrim Castle Dromore Rectory Ecclesville Demesne Seskinore Forest Associated Priority Acid grassland Habitats Lowland meadows Oakwoods Mixed ashwoods Associated Priority . Red squirrel Species . Common pipistrelle bat . Natterer’s bat . Song thursh . Starling Main threats/Local . Loss of veteran trees – ageing population. Issues/Comments . Competition with younger trees . Loss of deadwood . Damage to tree roots – poaching from livestock, eutrophication . Development . Disease
What is parkland?
Parkland is a special type of woodland that is generally not common in NI (NIBG, 2000). They are designed landscapes associated with significant houses or demesnes. There is generally a mosaic of habitats including open grown ancient trees set in pasture or heathland, specimen trees, boundary features, woodland blocks, streams, rivers and natural or constructed lakes (EHS, 2005). For the purpose of the NI HAP, parkland includes lands with “old veteran trees often associated with long-established woodland sites or sites that have been converted to other land uses such as arable farming, commercial forestry and amenity land, but where the surviving trees are of nature conservation interest” (EHS, 2005). Parklands are important for a wide variety of wildlife from vascular plants, mammals, birds and insects.
17 Current extent, status and distribution
The UK Biodiversity Steering Group estimate that there is between 10,000 ha and 20,000 ha of parkland in the UK. Within NI, there are varying estimates. Based on Graham, 1975, EHS have estimated there are approximately 1100 ha however according to the NICS 2000 there are approximately 383 ha in NI (Cooper et al, 2002). Due to the difficulties in defining this habitat, no total estimate is accurate and therefore should be taken as an under-estimate. However the portions that are defined as parkland have not been accurately surveyed for their condition, therefore little is known on their importance for biodiversity. Each site carries its own merits depending on past management regimes and potential nature conservation value. Some prime examples have been identified for reference by the NIBG namely Crom, Florence Court, Castle Coole, Belvoir Park and Lagan Valley Regional Park.
There are a few local examples of parkland within Omagh. Beltrim Castle estate in Gortin is home to a working farm and dwelling with mixed woodlands bordering the estate. These have a wide range of species including larch, beech, sycamore, Scots pine, oak and elm. Such mixed planting is common around Gortin and indeed occasional conifers have been planted in several streamside and riverside locations in the area as part of nineteenth century ‘landscaping’ (ERM, 1999). Derrybard near Fintona is extensive and is largely broadleaved, including ash, beech and oak, but there are some intermixed conifers. In parts, cherry laurel and snowberry dominate the understorey with a relatively poor herb layer, but where these shrubs are absent, it is more diverse and ferns and bryophytes are abundant. Many parklands have now lost some of their value and are being managed for other landuses such as Mountfield Lodge and Ecclesville Demesne. Other parklands within Omagh include Termon (Athenree), Lough Macrory Lodge, Church Hill in Gortin, Lisnamallard House and Seskinore Forest.
Significance for species
Parkland holds importance for local wildlife as has acted as a long standing refuge within a changing landscape and as stepping stones to other associated habitats such as heathland, meadows, oakwoods and mixed ashwoods. They are important for a wide variety of species from lower plants and invertebrates to birds, bats and mammals. Several NI priority species inhabit parklands including the red squirrel, several bat species, song thrush, starling and the barn owl. In addition, parklands in the west such as in Omagh support valuable communities of rare oceanic lichens (EHS, 2005).
18 Priority Habitat 3b: Mixed ashwoods
Summary table
Priority Type Mixed ashwoods Extent & Distribution Area Present 25.54 ha identified to date (EHS HST) Main Locations Dunaree Hill Willmount Glen Sloughan Glen Drummenagh Wood Associated Priority Purple moor-grass and rush pasture Habitats Calcareous grassland Lowland meadow Oakwood Wet woodland Associated Priority Bullfinch Species Starling Several bat species Main threats/Local Grazing, browsing and bark stripping by domestic Issues/Comments and feral stock Invasive species Lack of appropriate woodland management Habitat loss and fragmentation Disease
What are mixed ashwoods?
Mixed ashwoods are woodlands where ash is the dominant species in association with other broadleaf native species such as oak, downy birch and hazel. Other trees such as rowan and the non-native species sycamore and beech are common. Mixed ashwoods tend to occur on base-rich soils or on poorly drained acid soils where there is a flushing of nutrients. They support a rich and colourful ground flora of spring-flowering herbs such as wood-anemone, bluebell, primrose and herb-robert (EHS, 2005). To classify as mixed ashwood, woodlands need to be greater than 0.5ha in size, have 20% or more canopy cover, have within the canopy 50% or more local provenance tree species and exhibit a typical woodland ground flora.
Current extent, status and distribution
Mixed ashwoods are the main woodland type in NI on base-rich soils and locally prevalent in Co. Antrim and Co. Fermanagh. It is estimated that mixed ashwoods occupy a minimum of 3430ha in NI (EHS unpublished estimates, based upon Graham, 1975). Of this however, only a proportion could be
19 described as mature (i.e. less than 1000ha dates from before 1900) (EHS, 2005). Nevertheless, according to the NICS 2000, the landcover of broad leaved semi- natural woodland, of which mixed ashwoods are a component, has increased by 1249ha and now accounts for 1.7% of the landcover most likely due to increased tree planting and natural regeneration (Cooper & McCann, 2001). The condition of mixed ashwoods in NI is not currently known. This can be determined by a variety of factors including the percentage cover of native trees, the structure, the presence of key species and absence of invasive species.
As highlighted, within NI mixed ashwoods are typical of base rich soils found on the basalts of Co. Antrim and the limestones of Co. Fermanagh. Within Omagh, mixed ashwoods are localised, generally mixed with hazel and sometimes with oak. Examples include Dunaree Hill Wood, Drummenagh Wood, Sloughan Glen and Willmount Glen, all surveyed by the EHS Habitats Survey Team. Other localised pockets of mixed ashwood include Fallagh Burn Wood and Crowhill Wood, near Gortin. These woods also contain notable stands of downy birch, hazel and hawthorn. Throughout Omagh there may be other small, unidentified pockets of mixed ashwood that are locally important for wildlife.
Significance for species
As with all woodlands, wide varieties of species are supported by the complex woodland structure and microclimate. Mixed ashwoods are particularly noted for their rich ground flora and understory such as wood-sorrel, primrose, meadowsweet, herb-robert, wood anemone, wild strawberry, hazel scrub, guelder-rose and holly. Some NI priority species typical of ashwoods in Omagh include bullfinch, starling, bat species and the red squirrel.
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Priority Habitat 3c: Oakwood
Summary table:
Priority Type Oakwoods Extent & Distribution Area Present 190.96 ha identified to date (EHS HST) Main Locations Drumlea and Mullan Woods Owenkillew and Glenelly Woods Kirlish Wood Boorin Wood Glenlark Wood Associated Priority Upland heathland Habitats Purple moor-grass and rush pastures Lowland meadows Mixed ashwoods Wet woodland Parkland Associated Priority Red squirrel Species Common pipistrelle Song thrush Intermediate wintergreen Main threats/Local Grazing, browsing and bark stripping by domestic Issues/Comments and feral stock Invasive species Lack of appropriate woodland management Habitat loss and fragmentation Disease
What are oakwoods?
Oakwoods are woodlands where the two native oak species, sessile oak and pedunculate oak are dominant in association with other broadleaf native species such as downy birch, holly, rowan and hazel. They tend to occur on acidic soils derived from granite or other base-poor rocks (NIBG, 2000). The range of plants found in the ground layer varies according to the underlying soil type and degree of grazing but includes species such as bluebell, bramble, ferns, bilberry, greater woodrush and grasses such as wavy hair-grass. To classify as an oakwood, woodlands need to greater than 0.5ha in size, have 20% or more canopy cover, have within the canopy 50% or more local provenance tree species and exhibit a typical woodland ground flora.
21 Current extent, status and distribution
It is estimated that oakwoods occupy 2350 ha in NI (EHS unpublished estimates, based upon Graham, 1975), however only approximately 1400ha of this is considered mature (established before 1900) (EHS, 1995). Nevertheless, according to the NICS 2000, the landcover of broad leaved semi-natural woodland, of which oakwoods are a component, has increased by 1249ha and now accounts for 1.7% of the landcover most likely due to increased tree planting and natural regeneration (Cooper & McCann, 2001). The condition of mixed oakwoods in NI is not currently known. This can be determined by a variety of factors including the percentage cover of native trees, the structure, the presence of key species and absence of invasive species. Oakwoods are scattered throughout NI with many good examples in the Sperrins. In the west of NI including Omagh, the mild, moist climate provides favourable conditions for oakwoods to develop.
The EHS Habitat Survey Team have identified 190.96 ha of oakwood within the Omagh area, however this is not definitive. Many of the oakwoods in Omagh are associated with river valleys, two of which are designated as ASSI’s for their rich woodland flora and associated fauna. These are Drumlea and Mullan Woods ASSI, one of the largest areas of acid oakwoods in Northern Ireland (32 ha) and Owenkillew and Glenelly Woods ASSI, the largest intact semi-natural deciduous woodland block in the Omagh area (58 ha). Both woods exhibit classic compositions of sessile oak with frequent downy birch and occasional rowan and hazel. The understory varies between the two sites although both contain holly. The ground flora is similar in species including greater wood-rush, bilberry and bluebell with varying bryophyte cover. Drumlea and Mullan Woods are notable for the diversity and abundance of the bryophyte and lichen species present (EHS, 1994). Boorin Wood, part of which is in the Boorin NNR, is also acid oak woodland although there is an area of old willow carr as well as an area planted with beech (ERM, 1999).
Other notable oakwoods in the Omagh district include Glenlark Wood, Gorticashel Woods, Kirlish Wood and Cappagh Burn. Many of these woods are found in the Drumquin area, Bessy Bell and Gortin and South Sperrin LCA’s, areas that are notably important for oakwoods.
Significance for species
Oak trees are very important for biodiversity as they support the greatest assemblage of insects (284 as noted by Conservation Volunteers Northern Ireland). In turn this supports many more bird species and further up the food chain, mammals. Oakwoods are notable for their lower plant assemblages. The ferns, mosses and liverworts found in the most oceanic of these woods are
22 particularly rich containing many rare species including some fungi and lichen species. NI priority species that are associated with oakwoods in Omagh include the red squirrel, bat species, spotted flycatcher, song thrush and intermediate wintergreen.
23 Priority Habitat 3d: Wet woodland
Summary table:
Priority Type Wet woodland Extent & Distribution Area Present 46.26 ha identified to date (EHS HST) Main Locations Localised around lake fringes and on wet bog fringes Deroran Bog ASSI Cranny Bog Wood ASSI Tonnagh Beg Bog ASSI Associated Priority Fens Habitats Lowland raised bogs Reedbeds Crowfoot rivers Mesotrophic lakes Oakwoods Mixed ashwoods Associated Priority Various bat species Species Spotted flycatcher Song thrush Main threats/Local Inappropriate grazing regime Issues/Comments Invasive species Habitat loss and fragmentation Water level changes Nutrient enrichment Lack of appropriate woodland management Disease
What is wet woodland?
Wet woodlands are a range of woods that occur on poorly drained or waterlogged soils such as around lake shores, along streams, on hill-side flushes and as successional habitat on fens and cutover bogs (EHS, 2005). They are usually dominated by willow, alder or downy birch depending on the hydrological conditions and management of the wood and surrounding habitat. They often occur as habitat mosaics with other woodlands and boundaries are often gradual transitions (EHS, 2005). To classify as wet woodland, they need to be greater that 0.5ha in size, have 20% or more canopy cover, have within the canopy 50% or more local provenance tree species and exhibit a typical wet woodland ground flora.
24 Current extent, status and distribution
The historical large scale clearance of woodlands in NI means that much of the current wet woodland resource is largely secondary and of relatively recent origin (less than 100 years old). It is estimated that wet woodland occupies 2600ha in NI (EHS unpublished estimates, based upon Graham, 1975). This may be an underestimate due to the scattered and fragmented distribution of the woodland throughout NI. Cooper and McCann estimated the extent of fen carr (a type of wet woodland) at 3265ha in the NICS 2000. The condition of wet woodlands in NI is not currently known. This can be determined by a variety of factors including the percentage cover of native trees, the structure, the presence of key species and absence of invasive species.
Willow and birch dominated wet woodland are widespread throughout NI where the combination of open water or wet bog and woodlands occur. Important examples within NI include around Lough Neagh and Lough Erne. Wet woodlands tend to be scattered and small. Within Omagh wet woodland is largely confined to small patches within other woodland types or to inter-drumlin hollows where willow and alder are common with birch on slightly drier sites. In some inter-drumlin locations, the wet woodland forms a fringe around cut-over bog which may be colonized by almost pure birch scrub or woodland (ERM, 1999). Barra Glen near Carrickmore is steep hazel woodland that grades into wet willow woodland and wet grassland with fen meadow along the valley bottom. Another good example is Lower Carrigans Wood, which is dominated by downy birch and wetter areas having abundant alder and grey willow. The ground layer consists of broad buckler fern and soft rush with floating sweet-grass in the wetter areas. There are examples of raised bog fringed by wet woodland within the Omagh Farmland LCA. These habitats require appropriate management, as often, wet woodland encroaching the fringes of bog can be undesirable as the value of the bog is compromised. The designated raised bog sites Deroran Bog ASSI, Cranny Bog Wood ASSI, Tonnagh Beg Bog ASSI have fringes of wet woodland.
Significance for species
Wet woodland can be of significant value for flora and fauna depending in the predominant tree cover. The high humidity in wet woodland that favours a rich bryophte growth, also suits a large number of invertebrate species and in turn bats. The habitat is also suitable for otters and breeding birds. NI priority species that could be found in Omagh’s wet woodlands include the spotted flycatcher and song thrush. Other priority species such as many beetles and molluscs may be found in Omagh but have not yet been recorded.
25 Broad Habitat 4: Dwarf Shrub Heath
Dwarf shrub heaths are of international importance due to their limited distribution within Europe to the UK, RoI and western seaboard of mainland Europe. Heathland vegetation occurs widely on mineral soils and the peats (<0.5m deep) throughout the uplands and moorlands of the UK and RoI (EHS, 2003). They are characterised by a vegetation cover with greater than 25% of small gorse species. Although NI holds an important proportion of the heathland resource, it is relatively scarce because much has been lost through conversion to farmland, afforestation, urban development and scrub invasion (EHS, 2002) In NI there are three varying dwarf shrub heath habitats recognised as priority habitats; lowland heathland which is found below the upper limit of agricultural enclosure of approximately 300 metres, upland heathland which lies above the upper edge of agricultural land but below the montane limit (600 m) and montane heath above 600 metres.
Within the Omagh district, only the upland heathland priority habitat is found. According to the lowland heathland NI HAP, 2003, “lowland heathland is generally fragmented and restricted in its occurrence. It is largely confined to the lower slopes of the Mourne Mountains and the Ring of Gullion, Rathlin Island and narrow coastal strips in Counties Antrim and Down and small heathlands areas associated with some fens in Counties Down and Armagh”(EHS, 2003). Montane heath is found nearby in the highest peaks of the Sperrins, Sawel and Dart, just outside the Omagh district area.
26 Priority Habitat 4a: Upland heathland
Summary table:
Priority Type Upland heathland Extent & Distribution Area Present 3464.49 ha* Main Locations Carrickmore Hills Bessy Bell and Gortin LCA Murrins NNR/ASSI Boorin NNR Associated Priority Blanket bog Habitats Lowland heathland Lowland dry acid grassland Associated Priority Red grouse Species Hen harrier Curlew Irish hare Main threats/Local Lack of management Issues/Comments Overgrazing Invasive species Planning developments *estimated figure calculated from area of upland heathland within Forest Service Northern Ireland landholdings and area of upland heathland entered into the 2005/2006 Countryside Management Scheme, DARD, therefore not a total figure.
What is upland heathland?
Upland heathland is the habitat found in the higher slopes characterised by a variety of heather and small shrub species such as cross-leaved heath, bell heather and bilberry. It is similar to blanket bog however; the distinguishing features are the soil depth and absence of hare’s tail cotton grass. Upland heath occurs on mineral or peat soils <0.5 metres deep whereas blanket bog occurs on peat soils >0.5 metres deep. Therefore upland heathland is more characteristic of steeper slopes than blanket bog.
Current extent, status and distribution
Of the UK upland heathland resource of 2-3 million ha, NI has approximately 58,500 ha or 2.4% (Cooper and McCann, 2001). This estimation by Cooper and McCann from the NICS is the most accurate and up-to-date figure, however is considered an over estimation as was based on upland land classes of over 150m. Upland heathland is considered to occur generally over 300m. The NICS also estimated that between 1992 and 1998, wet heath mosaic and dry heath mosaic (both forms of upland heathland) have reduced by 20% and 28% respectively. The main cause for this loss is gradual habitat degradation of
27 the heath communities as a consequence of heavy grazing by sheep and occasionally cattle (EHS, 2003).
Agri-environment schemes such as Countryside Management Scheme (CMS) and Environmental Sensitive Areas (ESA) are helping to manage habitats such as upland heathlands for wildlife. Currently 27,000 ha of moorland with heather (which includes both blanket bog and upland heathland) are under agri- environmental schemes in NI, of which 3247.49 ha is in the Omagh area.
Within Omagh, upland heathland occurs below the standard 300m in areas such as the Murrins NNR/ASSI and Boorin NNR at approximately 200m. The NI HAP for upland heathland highlights Kirkpatrick’s observation that in the west of NI, the upper limit of agricultural enclosure can be as low as 120m.
Throughout Omagh, areas identified as important resources of upland heathland include the steeper slopes of Spaltindoagh, which provides ideal habitat for red grouse. Within the Brougher Mountain Landscape Character Area (LCA) cut- over blanket bog is extensive. Some of these patches that remain exhibit wet upland heathland vegetation however are classified as blanket bog due to the depth of peat. Within Slievemore LCA upland heathland is scattered, but not extensive, with common heather dominating (ERM, 1999). Upland heathland is widespread in the western half of the Carrickmore Hills LCA, with the Murrins a prime example. The Murrins showcases an excellent example of how varying habitats form mosaics. Part of the area is dominated by high glacial moraines where heath has developed on sands and gravels. Both wet and dry heath is present; on the gentle slopes of the eskers and on the steep, freely draining slopes of the shallow soils respectively. Heather, bell heather, tormentil, cross-leaved heath, purple moor grass and deergrass as well as bog moss varieties dominate the area. “Towards the bottom of the eskers, as the outwash plain levels out and the peat mantle becomes thicker and more waterlogged, the wet heath grades into blanket bog and the two communities often form complex mosaics”(EHS, 2005).
Like Slievemore, Beaghmore Moors and Marsh LCA exhibits small but notable patches of upland heathland often found overlaying gravel and fluvio-glacial deposits. Again in Bessy Bell and Gortin LCA, upland heathland, where found, grades into blanket bog. The vegetation is dominated by heather such as along the summit ridge from Liscabble Mountain to Curraghchosaly Mountain.
Significance for species
Upland heathland alone is less rich in species than some other habitats, however as it often forms part of an intimate mosaic with habitats such as acid grassland, fen and bog, it’s value increases for wildlife (NIBG, 2000). As detailed before, the habitat is built up of a variety of the main higher plants such as heather, bell heather, cross-leaved heath, bilberry and lesser twayblade. This then provides
28 the ideal habitat for some lower class plant species such as rare mosses, liverworts and lichens. Upland heathland is also important for many birds such as red grouse, merlin, hen harrier and curlew as well as mammals such as the Irish hare.
29 Broad Habitat 5: Fens, marsh and swamp
Fens, marsh and swamps are found in NI as fringe habitats adjacent to lakes and ponds. However, they frequently occur alone in low-lying wet ground or poorly drained marginal grassland that is not dominated by grasses (NIBG, 2000).
Within the broad habitat of fens, marsh and swamp, there are three priority habitats found in NI; fens, purple moor grass and rush pastures, and reedbeds. All three priority habitats occur in Omagh.
30 Priority habitat 5a: Fens
Summary table:
Priority Type Fens Extent & Distribution Area Present Not known Main Locations Fairy Water Bogs Fringing around small loughs Associated Priority Reedbeds Habitats Purple moor grass and rush pastures Wet woodland Mesotrophic lakes Eutrophic standing waters Associated Priority Curlew Species Redshank Reed bunting Grasshopper warbler Lapwing Main threats/local Drainage issues/comments Inappropriate grazing Eutrophication Peat-cutting
What is a fen?
A fen is a wetland with a permanently high water level at or just below the surface (EHS, 2002). They are minerotrophic, meaning they receive water and nutrients from soil, rock and groundwater. Fens can be further subdivided into many categories according to the rock substrate below, their location in river valley basins, floodplains or on higher ground adjacent to blanket bogs and their occurrence beside other habitats. Distinguishing fen from a range of closely associated priority habitats can be difficult as they often occur within a matrix of raised bog, wet grassland, open water and wet woodland plant communities (EHS, 2005). However, for the purpose of this audit, fen will be accounted for if they exhibit the characteristic vegetation communities including floating sedges and mosses such as bottle sedge, creeping bent and many varying bog mosses. Other herbaceous wetland plants include bogbean, lesser spearwort and marsh cinquefoil. They are typically found in river valleys, poorly drained basins or hollows and beside open stretches of water.
Current extent, status and distribution.
The NICS 2000 (Cooper and McCann, 2001) estimated that lowland fen (occurring in lowland land-classes) covers 2950ha in NI. This is considered a
31 minimum estimate as other similar habitats, poor fen and fen meadow normally associated with purple moor grass and rush pasture can be included in ‘fens’ when occurring on deep peat. Fen surveys conducted by EHS to identify ASSI’s and smaller surveys in Co. Antrim, Co. Tyrone and parts of Co. Fermanagh have shown that NI holds a significant proportion of the UK fen resources in terms of extent and habitat diversity and quality (EHS, 2005). Protected fen sites in NI are surveyed to determine their condition. “A preliminary evaluation indicates that a significant proportion of fen vegetation is in unfavourable condition (EHS, 2005). Non-statutory fen sites are also presumed to have unfavourable conditions and are also most likely applicable to Omagh. This is mainly due to a combination of nutrient enrichment, drainage and lack of management.
Overall, fens are of limited occurrence in Omagh and are mainly confined to small lake fringes or inter-drumlin hollows. There were 7.77 ha of fens entered into the agri-environment schemes in 2005/2006. Those noted in the landscape character area assessments 1999 (LCA’s) include Lough Muck and Loughnagin in the Omagh Farmland LCA, Meenacloy and Lough Corr in Lough Bradan LCA, Ballydoolagh and Largy Lough in Brougher Mountain LCA. Of most notable importance for wetlands in Omagh are the Fairy Water Bogs. This ASSI/SAC and ramsar site is considered to comprise one of the most important concentrations of lowland raised bogs in NI and also displays an important mosaic of wetland habitats. “Annaghs Lough at the margin of Bomackatall Bog shows various stages in the vegetation succession from open water to peaty swamp and fen” (Acer environmental, 1995).
Significance for species
Fens and associated habitats are extremely important for biodiversity in NI and consequently Omagh. They support many types of flora and fauna for plants in particular, they are thought to support up to two hundred different species (O’Connell, 1987). Some of the rarer priority species that occur within NI include fen bedstraw, greater water parsnip, holy grass, Irish lady’s tresses, marsh helleborine and marsh pea. None of these have been recorded in Omagh to date. Other fen plants occurring in Omagh include gypsywort, cowbane, great fen-sedge, common butterwort and many types of sedge. This damp floral habitat supports a diverse range of invertebrates. Again, of nature conservation importance these include dragonflies such as the Irish damselfly, beetles such as the whirligig beetle and butterflies and moths such as the marsh fritillary butterfly (EHS, 2005). The smooth newt, Northern Ireland’s only newt species, is commonly found in fen wetlands. Breeding waders including snipe, curlew and lapwing depend on fen wetlands habitats.
32 Priority habitat 5b: Purple moor-grass and rush pastures.
Summary table:
Priority Type Purple moor-grass and rush pastures Extent & Distribution Area Present Not known Main Locations As habitat mosaics with associated priority habitats e.g. Fairy Water Valley Blackhill bog Killen Lough Dunaree Hill Associated Priority Lowland meadow Habitats Fens Coastal floodplain and grazing marsh Associated Priority Curlew Species Skylark Reed bunting Main threats/Local Agricultural improvement Issues/Comments Inadequate grazing regime Abandonment Afforestation Infilling . Habitat fragmentation
What is purple moor-grass and rush pasture?
Purple moor-grass and rush pasture occurs on poorly drained usually acidic soils in lowland areas of high rainfall in western Europe. It is often found as fragments within farmland in wet hollows or field corners and grades into other habitats; agricultural grasslands in lowlands and poor fen and wet heath in uplands (EHS, 2005). They have distinctive vegetation cover of species typical of fen meadow and rush pasture and generally include a rich variety of grasses such as purple moor- grass, quaking grass, sedges such as carnation sedge, flea sedge and tawny sedge and rushes with a mixture of herbaceous wetland plants including orchids, wild angelica, meadow thistle, tormentil, devil’s-bit scabious and selfheal. A species rich mix is essential to be classified as purple moor-grass and rush pasture priority habitat.
33 Current extent, status and distribution
NI is estimated to hold one third (18,700ha) of the total UK purple moor-grass and rush pasture habitat therefore has a responsibility both in the UK and Europe to protect, conserve and enhance this habitat (EHS, 2005). Outside of Fermanagh, this habitat is scattered. Based on the NICS 2000, NI has lost approximately one third of its purple moor- grass and rush pasture habitat between 1991 and 1998 with a current (2004) estimate of 18,919ha. Of this, 652ha occurs within the Sperrin AONB which includes the North East quarter of Omagh district. Although not an accurate figure for Omagh district, it shows that purple moor-grass and rush pasture does not occupy any significantly large areas of Omagh. The NICS 2000 figures for Sperrin AONB show a significant decline in species rich wet grassland by 47% between 1991 and 1998, most likely due to conversion to agricultural grassland. However, an increase in fen meadow by 20% and in Molinia grassland by 67% was recorded, most likely due to an increased cover of hill grasses and mosses on dry bog (Cooper and McCann, 2001).
Locally, with the Omagh district, purple moor-grass and rush pasture are found as part of a habitat mosaic with fens, wet heaths, dry grasslands, swamps and flushes. Within the inter-drumlin landscape in central Omagh, small patches of marshy grassland can be found where flushing has occurred. Again, the Fairy Water valley provides a suitable wetland habitat and purple moor-grass and rush pastures are found where ground water fluctuates more greatly in small patches of farmland. Similar localised conditions provide ideal habitat for purple moor- grass and rush pasture in Drumquin and other river valleys. Small patches of purple moor-grass and rush pasture have been identified alongside many blanket bogs and lake margins such as Drumash near Trillick, Blackhill bog near Omagh, Killen Lough and Loughnagan raised bog near Drumquin. They can also occur in association with woodland such as at Dunaree Hill, where purple moor-grass pasture and mixed ash woodland occupies 51.54 ha.
Significance for species
Purple moor-grass and rush pasture combined with adjacent priority habitats provide the ideal habitat for some of NI priority species. Those that occur in Omagh include birds such as the skylark, curlew and reed bunting and invertebrates such as the marsh fritillary butterfly.
34 Priority Habitat 5c: Reedbeds
Summary table:
Priority Type Reedbeds Extent & Distribution Area Present Not known Main Locations Narrow strips along lake margins e.g. Lough Muck, Drumquin Lough Fairy Water Valley Associated Priority Fens Habitats Coastal floodplain and grazing marsh Lowland raised bog Wet woodland Mesotrophic lakes Eutrophic standing waters Associated Priority Otter Species . Reed bunting Main threats/Local Drainage Issues/Comments Fly-tipping Eutrophication
What are reedbeds?
Reedbeds are swamp communities that contain tall emergent vegetation typical of the transition between open water and exposed land (JNCC, 1990). The water table is at or above ground level for most of the year. They are usually distributed on the margins of water bodies such as streams, estuaries, sewage treatment works and as successional habitats on fens and bogs. Reedbeds are amongst the most important habitats for birds in the UK. To be classified as a reedbed for the purpose of the NI HAP they must contain more than 30% cover of common reed, have a reedbed area greater than 0.5 ha and width of at least 5 metres (EHS, 2005).
Current extent, status and distribution
The NICS 2000 estimated that reedbeds occupy 3228ha in NI, a significant resource. Historically in the UK, there have been significant losses of reedbeds, however according to the NICS 2000, there have been little significant losses in NI between 1988 and 1998 (Cooper et al, 2002). The condition of reedbeds is assessed if part of designated sites. Structure and dominance of common reed are noted as they are important for the many species this habitat supports.
35 Within NI several large areas (greater than 10ha) occur around both Lough Neagh and Upper Lough Erne and these are in fact the largest examples in NI (Brown et al, 1991). Reedbeds in Omagh occur as a part of a habitat mosaic as with fens and purple moorgrass and rush pasture. They are found locally as narrow strips along lake margins such as in Lough Muck, Drumquin Lough and within the Fairy Water Valley, Killee Lough. Omagh district does not hold any significant areas of stand alone reedbeds. Only 0.3ha was entered into an agri-environment scheme in Omagh in 2005/2006.
Significance for species
Reedbeds are of value for a range of specialist bird species including the reed bunting, water rail, sedge warbler and locally the reed warbler (EHS, 2005). They also provide excellent nesting cover for waterfowl such as the great-crested grebe.
As part of a habitat mosaic, reedbeds provide a valuable habitat for many species, up to 700. (EHS, 2005). Locally in Omagh, the otter is found on many of these wetland mosaics.
36 Broad Habitat 6: Improved grassland
This is the most extensive broad habitat in NI. It is formed from semi-natural grasslands that have been made more productive for livestock or ‘improved’ by intensive treatments. At its most radical, this process entails the complete replacement of the original sward i.e. ploughing and reseeding (NIBG, 2000). This broad habitat contains one priority habitat found in the Omagh district; coastal and floodplain grazing marsh.
37 Priority Habitat 6a: Coastal and floodplain grazing marsh
Summary table:
Priority Type Coastal and Floodplain grazing marsh Extent & Distribution Area Present Not known Main Locations Occurs as wetland habitat mosaic in wide floodplains e.g Fairy Water Valley Associated Priority Purple moor-grass and rush pastures Habitats Lowland raised bog Fens Reedbeds Wet woodland Associated Priority Curlew Species Lapwing Redshank. Main threats/Local Drainage Issues/Comments Agricultural improvement Inappropriate grazing regime Fragmentation
What is coastal and floodplain grazing marsh?
Coastal and floodplain grazing marsh is defined un the UK Habitat Action Plan (HAP) as periodically inundated pasture, or meadow with ditches which maintain the water levels, containing brackish or fresh water (EHS, 2005). As the name suggests there are two types; coastal and floodplain, of which only the latter exists in the landlocked Omagh district. Floodplain grazing marsh is associated with large slow-flowing rivers as well as lakes where it can be drained by a network of ditches (EHS, 2005). Much of the floodplain grazing mash which exists today was formerly swamp, woodland, fen or reedbed. The characteristic vegetation associated with floodplain grazing marsh is rush dominated pasture and semi-improved and improved grassland often over peaty ground (EHS, 2005).
Current status, extent and distribution:
Estimates of the extent of coastal and floodplain grazing marsh in the UK are not accurate, however it is thought that there may be a total of 300,000ha of which NI is thought to contain an important proportion based on breeding wader populations. In NI, little has been done to quantify the extent of coastal and floodplain grazing marsh. The NICS 2000 does not directly quantify grazing marsh however it does provide as estimate of the area of species rich wet grassland which roughly
38 equates to floodplain grazing marsh. In 1998 there were 13,808ha of species rich wet grassland in NI, which was a significant decrease from 1991 of 37%. The reason for this decline was mainly conversion to agricultural grassland.
The Northern Ireland Breeding Wader Survey, surveyed lowland damp grasslands for breeding waders which, probably roughly equates to this habitat type. The survey identified 615 lowland damp grassland sites within NI with important concentrations occurring around Lough Neagh (3,284ha) and Upper Lough Erne (2,922ha). Follow up surveys have indicated that there have been significant losses of this habitat type since this survey (EHS, 2005). In 2005, there were approximately 506ha of breeding wader sites in NI, of which 45.39 ha were in Omagh (which indicates the presence of coastal and floodplain grazing marsh) under agri-environment agreement (DARD, 2005) and these sites are managed for nature conservation
Within Omagh, these grazing marshes can form mosaic with other wetland habitats such as purple moor grass and rush pastures, lowland raised bogs, reed beds and fens. There is little information on the location of these within Omagh, but we can only presume that they exist in areas of suitable conditions such as in the Fairy Water Valley.
Significance for species
As part of the wider wetland habitat mosaic, grazing marshes support a number of breeding wader bird species that have been recorded in Omagh including snipe, curlew, lapwing and redshank. However, these rare species have exhibited population declines in the past particularly due to the loss of wet flooded grasslands via drainage and agricultural improvement (EHS, 2005).
39 Broad Habitat 7: Neutral grassland
Neutral grasslands are one of the three main types of semi-natural grasslands that occur within NI. Neutral grasslands are intermediate in character between calcareous and acid grasslands. This broad habitat type includes one priority habitat; lowland meadows which occurs in the Omagh district.
40 Priority Habitat 7a: Lowland meadow
Summary table:
Priority Type Lowland meadow Extent & Distribution Area Present Not known Main Locations Small field parcels throughout Omagh and concentrated in Lough Bradan LCA Associated Priority Purple moor-grass and rush pasture Habitats Coastal and floodplain grazing marsh Fens Associated Priority Irish hare Species Skylark . Pink meadow waxcap Main threats/Local Agricultural improvement Issues/Comments Abandonment . Habitat fragmentation . overgrazing
What is a lowland meadow?
A lowland meadow is defined in the NI HAP as unimproved neutral grassland found on enclosed land, normally on a well-drained mineral soil with a herb-rich sward (EHS, 2005). Such meadows are found in former hay meadows or in non- agricultural sites such as churchyards or roadside verges. However, they are defined for this HAP as grasslands that have a high percentage cover (>30%) of fine-leaved grasses such as common bent and red fescue, an absence or low percentage of rye grasses, a minimum of 10 higher plant species in a 4m2 quadrat such as meadow vetchling, common knapweed and yellow-rattle and <25% dwarf shrub cover.
Current extent, status and distribution
The area of lowland meadow in NI represents a large proportion of the UK resource estimated at approximately 4655 ha in 1998 by the NICS 2000, which examined the lowland classes of species-rich hay meadows (Cooper & McCann, 2001). These do not cover large areas but rather small fragmented field parcels where agricultural operations may be difficult (EHS, 2005). Lowland meadows in the UK and NI have undergone considerable contraction and degradation mainly due to conversion to agricultural grasslands and changing agricultural practices. There has been a major contraction of the area used for hay production as many more cattle are now over wintered indoors and
41 silage production with multiple cuts of nutrient-demanding grasses, has become prevalent (EHS, 2005).
Within NI, lowland meadows are concentrated in the south and east of the Province. However, the meadows display a transition to wetter grassland types in the west of the Province (EHS, 2005). Within Omagh there are few records of this neutral grassland although a few have been identified, surveyed and deemed of nature conservation importance and include this westerly transition of wetter flushes. Such areas include parcels of fields near Seskinore and near Drumquin. They are also more common in the west of Omagh namely within the Lough Bradan LCA where “many of the fields are traditionally managed for grazing of beef cattle and sheep and can be quite diverse; common species include sweet vernal grass, common bent, crested dog’s tail, meadow fescue and soft rush or jointed rush” (ERM, 1999).
Significance for species
Typically lowland meadows will contain a wide variety of higher plants such as frog orchid, northern marsh-orchid and butterfly orchids. The fungi, pink meadow cap, also a priority species can be found in this habitat in Omagh. Lowland meadows as part of a habitat mosaic with dry acid grassland, purple moor-grass and rush pasture has in the past supported breeding corncrake in the Omagh district and also supports skylark and Irish hare.
42 Broad Habitat 8: Standing open water and canals
“Open water is defined as water lying beyond the limits of swamp or emergent vegetation, although it may contain submerged, free floating or floating-leaved vegetation” (JNCC, 1990). Standing water includes lakes, reservoirs, pools, ponds, ditches, canals and brackish lagoons. They are one of NI’s most extensive natural habitats with over 1600 lakes ranging from the largest, Lough Neagh to small ponds (NIBG, 2000). Most standing water bodies are broadly classified by their level of nutrients: eutrophic (high), mesotrophic (medium) and oligiotrophic (low) (EHS, 2005). These levels fluctuate however throughout the seasons and over a longer period of time due to natural and human influenced reasons, therefore it is more accurate to say that trophic state is a continuum between oligiotrophic and eutropic status. It is important to note however, that many lowland water bodies in the UK are now heavily polluted, with nutrient concentrations far in excess of the levels stated (UK Biodiversity Group, 1998). Aquifer fed naturally fluctuating bodies (turloughs), eutrophic standing waters, mesotrophic lakes and marl lakes are all NI priority habitats under the broad habitat type of standing open water and canals. Only eutrophic and mesotrophic lakes occur in the Omagh district.
The distribution and condition of NI’s lakes has been assessed through a combination of commissioned research and surveys carried out by EHS staff and an annotated inventory and comprehensive survey by Smith et al 1991 and Wolfe-Murphy et al 1992 known as the Northern Ireland Lake Survey (NILS).
43 Priority habitat 8a: Eutrophic standing waters
Summary Table:
Priority Type Eutrophic standing waters Extent & Distribution Area Present 26.25 ha (NILS) Main Locations Small and localised Aghlisk Lough Galbally Lough Maghera Lough Lough Muck Fireagh Lough Associated Priority Fen Habitats Wet woodland Coastal and Floodplain grazing marsh Purple moor-grass and rush pasture Lowland raised bog Reedbed Associated Priority Otter Species Main threats/Local Eutrophication Issues/Comments Drainage Water abstraction . Changes in landuse . Litter
What are eutrophic standing waters?
Eutrophic standing waters are those bodies of water that have high nutrient levels i.e. ≥0.035 mg l-1 total phosphorus and ≥0.5 mg l-1 total inorganic nitrogen. In their natural state, eutrophic standing waters have high biodiversity; planktonic algae and zooplankton are abundant in the water column, submerged vegetation is diverse and numerous species of invertebrate and fish are present (EHS, 2005). They are characterised by having dense, long-term populations of algae in mid-summer often making the water green. Characteristic aquatic plants vary from region to region depending on nutrient levels and exposure however typical species include duckweeds, yellow water-lily and spiked water-milfoil (EHS, 2005).
44 Current extent, status and distribution
In the UK there is approximately 1785km2 of eutrophic standing waters of which NI holds just over 50%, therefore NI holds a high proportion of the national resource (EHS, 2005). Lough Neagh and Lough Erne are the two largest eutrophic standing waters in NI, combined covering 530km2, 56% of NI’s resource. In fact Lough Neagh is the largest area of freshwater in the UK and RoI.
Within Omagh, of 38 lakes surveyed in the 1992 NILS, 6 or 16% were found at survey time to be classified as eutrophic standing waters. These 6 lakes cover an area of 26.25ha which is approximately 15% of the total lake area in Omagh, 179.25 ha. Little is presently known about the condition of NI’s lakes however work is ongoing to assess if water bodies are achieving Good Ecological Status. As previously explained however, the nutrient status of lakes is continually changing due to natural and human influenced reasons, therefore it is more accurate to say that trophic state is a continuum between oligotrophic and eutrophic status. Overall, the quality of NI’s lakes is declining primarily due to localised pollution and artificial eutrophication.
Lakes are not common in Omagh, however they are found in concentrations throughout the district e.g. within the Murrins NNR/ASSI area, Boorin NNR and low-lying inter-drumlin valleys. Only a few of these lakes that have been surveyed have been classified as eutrophic standing waters and these include Aghlisk Lough, Galbally Lough and Maghera Lough within the Irvinestown Farmland LCA; Lough Muck and Fireagh Lough in the Omagh Farmland LCA. Other unidentified eutrophic standing waters may occur.
Significance for species
As well as the typical aquatic plant species that eutrophic standing water supports, other rarer plants occur in some lakes e.g. slender-leaved pondweed and the rare pointed stonewort which occurs in Co. Fermanagh. Eutrophic standing water bodies form important mosaics with adjacent habitats such as fen, wet woodland, reedbed and coastal and floodplain grazing marsh, which combined, support internationally important bird populations such as snipe, redshank, lapwing and curlew at lakes such as Lough Neagh and Lough Beg.
Eutrophic standing waters support a mixture of coarse and salmoid fish species such as roach, perch, bream, brown trout and Atlantic salmon. The pollan, a glacial relict species still remains in Lough Neagh and Lough Erne and is also a NI priority species (EHS, 2005).
45 These lakes also support many invertebrates such as dragonflies, water beetles, stoneflies and mayflies as well as bottom dwelling invertebrates such as snails, freshwater crayfish and the larval stages of dragonflies, stoneflies and mayflies. A locally important species to Omagh that relies on freshwater lakes for food and habitat is the otter, a NI priority species.
46 Priority habitat 8b: Mesotrophic lakes
Summary table:
Priority Type Mesotrophic lakes Distribution Area present 15.25 ha Main Locations Drumquin Lough Killen Lough Lough a Vigh Loughnagay Lough Creggan Associated Priority Fen Habitats Wet woodland Coastal and Floodplain grazing marsh Purple moor-grass and rush pasture Lowland raised bog Reedbed Associated Priority Otter Species Main threats/Local Eutrophication Issues/Comments Changes in land use Invasive species . Drainage . Water abstraction . litter
What is a mesotrophic lake?
Mesotrophic waters can be defined as those capable of supporting a diverse macrophytic flora but with relatively clear water, reflecting limited growth of planktonic and filamentous algae. They support a higher diversity of submerged macrophytes than any other standing water type (EHS, 2005). Although it is difficult to define the nutrient status between mesotrophic and eutrophic standing waters, the levels set within the UK Mesotrophic lake HAP are as follows; Nitrogen 0.3 – 0.65 mg N-1, Phosphorus 0.01 – 0.03 mg P-1 Characteristic aquatic plants of mesotrophic lakes include the white water-lily, yellow water lily and several pondweeds and stoneworts (EHS, 2005).
47 Current extent, status and distribution
Mesotrophic lakes are relatively infrequent in the UK, being largely confined to the margins of uplands in the north and west (UK Biodiversity Steering Group, 1998). The UK mesotrophic lake inventory listed approximately 600 known lakes, of which a high proportion is in NI (NIBG, 2000). Within Omagh, there were 10 mesotrophic lakes identified in the NILS, covering a combined area of 15.25 ha. These mesotrophic lakes are small and relatively frequent with an average size of 1.5ha.
Within the Fairy Water valley LCA a small concentration occurs including Drumquin Lough, Claraghmore and Killen Lough. In the east of Omagh within the Beaghmore Moors and Marsh LCA several mesotrophic lakes lie; Lough Nanallog and Loughnagay.
Significance for species
Similar to eutrophic lakes, mesotrophic lakes support a mixture of coarse and salmoid fish species such as roach, perch, bream, brown trout and Atlantic salmon. The Arctic charr, a NI priority species is also characteristic of mesotrophic lakes, however is only found in Lough Melvin of Co. Fermanagh. The brown trout has three distinct races also found in Lough Melvin. Again, similar to eutrophic lakes, mesotrophic lakes support many invertebrates such as dragonflies, water beetles, stoneflies and mayflies as well as bottom dwelling invertebrates such as snails, freshwater crayfish and the larval stages of dragonflies, stoneflies and mayflies. Other priority species that occur in mesotrophic lakes in Omagh are the otter and in parts the white-clawed crayfish.
48