NationalNational SurveySurvey ofof NativeNative WoodlandsWoodlands 20032003 --20082008 Volume I: Main report Philip Perrin, James Martin, Simon Barron, Fionnuala O’Neill, Kate McNutt & Aoife Delaney Botanical, Environmental & Conservation Consultants Ltd. 2008 A report submitted to the National Parks & Wildlife Service Executive Summary The National Survey of Native Woodlands in Ireland included the survey of 1,217 woodland sites across all 26 counties of the Republic of Ireland during 2003-2007. Site selection was carried out using the Forest Inventory Planning System 1998 (FIPS) and local knowledge. Surveys comprised the recording of site species lists and information at the site level on topography, management, grazing, natural regeneration, geographical situation, adjacent habitat types, invasive species, dead wood and boundaries. Relevés were recorded in each of the main stand types identified at each site. For each relevé, data were recorded on vascular plant and bryophyte cover abundance, soil type and soil chemistry, notable lichens, stand structure, and natural regeneration. Data were also incorporated from a number of external sources. This resulted in a database with data from 1,320 sites and 1,667 relevés. The relevé dataset was analysed using hierarchical clustering and indicator species analysis. Four major woodland groups were defined: Quercus petraea – Luzula sylvatica (260 relevés), Fraxinus excelsior – Hedera helix (740 relevés), Alnus glutinosa – Filipendula ulmaria (296 relevés) and Betula pubescens – Molinia caerulea (371 relevés). Further analysis of the dataset divided these four groups into twenty-two vegetation types. For each vegetation type a synoptic table of the floristic data was produced, together with a list of key indicator species, a list of example sites, summary environmental and stand structure data and a distribution map. A range of data types from both the general site survey (e.g. area, occurrence of rare species, presence of hydrological features) and the relevé dataset (e.g. structural diversity, regeneration status) was used to produce a conservation score for each of the woodlands surveyed. This score allows the relative conservation value of each site to be assessed, and provides baseline data which can be used when monitoring sites in the future. A notable finding was that the west of the country contained 20 of the 27 top-ranked sites. In addition, all of these top-ranked sites have NHA and/or SAC designation. A number of sites that ranked highly in the conservation assessment lack any designation; these have been highlighted as being worthy of further examination. A threat score was also produced based on general site survey and relevé data to give an indication of the threats posed to woodlands from primarily internal sources, such as invasive species infestation. These threat scores should be regarded as the minimum threat potential to Irish woodlands as, for example, sites at which invasive species are a major problem may have failed to meet the criteria for survey. Guidelines are given in this document for the monitoring of the four Annex I woodland habitats that occur in Ireland. For each Annex I habitat assessment three parameters are scored: area, structure and functions, and future prospects. Threshold values for each of these parameters are given and the recommended methodology for carrying out the monitoring assessments is laid out. The outputs of the NSNW will provide a valuable resource for environmental managers, ecological researchers and policy makers to work towards the conservation of Irish woodlands. The National Survey of Native Woodlands 2003-2008 Volume I - BEC Consultants Ltd. BOTANICAL , ENVIRONMENTAL & CONSERVATION CONSULTANTS LTD www.botanicalenvironmental.com 27 Upper Fitzwilliam Street, Dublin 2. Tel: 01 6328615/616, Fax: 01 6328601 Email: [email protected] Acknowledgements The National Survey of Native Woodlands 2003-2008 has been one of the largest ecological surveys to be completed in Ireland. It would not have been possible without the hard work and assistance of a large number of people and to these the authors extend their gratitude. Fieldwork: Amanda Browne, Edwina Cole, Mihai Coroi, Kieran Connolly, John Cross, Jenny Dowse, Fiona Dunne, Janice Fuller, Mairéad Gabbett, Thérèse Higgins, Lisa Kilmartin, Maria Long, Róisín McCauley, Mark Clancy, Mark McCorry, Steve McCormack, Chris McMahon, Mieke Muyllaert, Saoirse O'Donoghue, Eileen Power, Anna Robinson, Jenni Roche, Niamh Roche, Louise Scally, George Smith and Aisling Walsh. External data sources: Amanda Browne, Willie Crowley, Fiona Dunne, M. Fanning, Susan Fuller, Daniel Kelly, Mark McCorry, Alan Poole, Niamh Roche, Sasha Bosbeer, George Smith and Fernando Valverde. Technical support and advice: John Cross, Maria Cullen, Andrew Fitzgerald, Howard Fox, Naomi Kingston, Deirdre Lynn, Aileen O’Sullivan, Sylvia Reynolds, George Smith and Steve Waldren. We are further indebted to the many BSBI recorders, NPWS staff and other recorders who suggested sites for survey and the many, many landowners who permitted us to survey their lands and were forthcoming with background information. This study has been funded by the National Parks and Wildlife Service (Department of the Environment, Heritage & Local Government) and the Forest Service (Department of Agriculture, Fisheries & Food). Cover photo: Vernal carpet of Allium ursinum and Anenome nemorosa beneath canopy of Fraxinus excelsior , Hazel Wood, Co. Monaghan (Philip Perrin, April 2005) The National Survey of Native Woodlands 2003-2008 Volume I: Main Report Contents Page Executive summary Acknowledgements Contents 1 Introduction 1 1.1 Rationale 1 1.2 Studies of Irish woodlands 1 1.3 Classification of Irish woodlands 2 1.4 Extent of Irish woodlands 4 1.5 Threats to Irish woodlands 7 1.6 Conservation of Irish woodlands 7 1.7 Aims of the project 9 1.8 Structure of the report 9 2 Methods 13 2.1 Site selection 13 2.2 General site survey 15 2.3 Relevé survey 18 2.4 Incorporation of external data 19 2.5 Identification of Annex I habitats and compilation of monitoring guidelines 21 2.6 Conservation and threat assessment 22 2.7 Vegetation analysis 26 3 Results 31 3.1 Coverage of the survey 31 3.2 Area 32 3.3 Landscape features 33 3.4 Adjacent land cover 34 3.5 Invasive species 36 3.6 Management and land use 37 3.7 Grazing 40 3.8 Hydrological and man-made features 41 3.9 Stand structure 42 3.10 Merchantable timber 49 3.11 Species richness 50 3.12 Natural regeneration 53 3.13 Dead wood 56 3.14 Lichens 57 3.15 Notable species 57 3.16 Species frequency 58 3.17 Vegetation analysis 61 3.18 Conservation assessment 63 Page 3.19 Threat assessment 65 4 Discussion 69 4.1 Critique of existing classifications 69 4.2 Conservation status of Irish woodlands 74 4.3 Utilisation of the data set 76 4.4 Concluding remarks 77 References 79 Technical Addendum: Annex I woodland habitat monitoring guidelines 83 List of Appendices Appendix 1: Native status of trees in Ireland 95 Appendix 2: Field sheets 96 Appendix 3: Frequency of species recorded 103 Appendix 4: Conservation scores 115 Appendix 5: Top-ranked sites by county 150 Appendix 6: Threat scores 157 List of Tables Table 1.1 Relationship between phytosociological scheme of Kelly (2005) and woodland 3 classification of Cross (2005) Table 1.2 Area and density of native woodland by county. 6 Table 1.3 Size of contiguous broadleaf or broadleaf / conifer units in FIPS 1998 6 Table 2.1 Definition of grazing levels 17 Table 2.2 Classification of Rhododendron infestation (Cross 1981, 1982) 17 Table 2.3 Classification of invasive shrubs and herbs (excluding Rhododendron ) 18 Table 2.4 Criteria used in the calculation of the conservation score of each site 24 Table 2.5 Notable species used as part of the conservation assessment 25 Table 2.6 Criteria used in the calculation of the threat score of each site 25 Table 3.1 Number of sites surveyed, number of relevés recorded and number of Annex I 32 habitat relevés by county Table 3.2 Frequency of recording of adjacent land use classes using the categories of 35 Fossitt (2000) Table 3.3 Frequency in percent of selected invasive tree species at sites and within four 37 size classes Table 3.4 Frequency and basal area of adult trees and stems by species 45 Table 3.5 Frequency of stems of merchantable size by species 49 Table 3.6 Frequency of viable log length and stem defects by species 50 Table 3.7 Most frequently regenerating tree species 53 Table 3.8 Most frequently recorded lichen species 57 Table 3.9 Frequency of records for notable vascular plant 58 Table 3.10 Species occurring in more than 50% of sites surveyed 60 Table 3.11 Overview of the native woodland classification scheme 61 Page Table 3.12 The top 27 sites ranked by conservation assessment score 64 Table 3.13 The top 19 undesignated sites ranked by conservation assessment score 65 Table 3.14 The top 21 sites ranked by threat assessment score 67 List of Figures Fig. 1.1 Extent in Ireland of (a) all forested land and (b) mixed and broadleaved 5 woodland not dominated by beech. Fig. 1.2 Area and density of native woodlands by county. 5 Fig. 2.1 Overlay of FIPS on six inch map for Ballykeefe Nature Reserve, Kilkenny 14 Fig. 2.2 Aerial photograph for Ballykeefe Nature Reserve, Kilkenny 14 Fig. 3.1 Coverage of the survey on hectad (10 km x 10 km square) basis 31 Fig. 3.2 Area of surveyed sites 33 Fig. 3.3 Frequency of landscape features associated with surveyed sites 34 Fig. 3.4 Frequency of invasive shrub species 36 Fig. 3.5 Frequency of observed management and land use at surveyed sites 38 Fig. 3.6 Frequency of different grazing levels 40 Fig.