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 BLANK PAGE 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 2 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. 6 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