Condition Assessment of Eight Standing Waters in Welsh Sites of Special Scientific Interest (Sssis)
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Condition Assessment of Eight Standing Waters in Welsh Sites of Special Scientific Interest (SSSIs) Goldsmith B, Shilland EM, Yang H, Shilland J, Salgado J & Turner SD. ENSIS Ltd, London NRW Evidence Report No. 29 www.naturalresourceswales.gov.uk Date About Natural Resources Wales Natural Resources Wales is the organisation responsible for the work carried out by the three former organisations, the Countryside Council for Wales, Environment Agency Wales and Forestry Commission Wales. It is also responsible for some functions previously undertaken by Welsh Government. Our purpose is to ensure that the natural resources of Wales are sustainably maintained, used and enhanced, now and in the future. We work for the communities of Wales to protect people and their homes as much as possible from environmental incidents like flooding and pollution. We provide opportunities for people to learn, use and benefit from Wales' natural resources. We work to support Wales' economy by enabling the sustainable use of natural resources to support jobs and enterprise. We help businesses and developers to understand and consider environmental limits when they make important decisions. We work to maintain and improve the quality of the environment for everyone and we work towards making the environment and our natural resources more resilient to climate change and other pressures. www.naturalresourceswales.gov.uk Page 1 Evidence at Natural Resources Wales Natural Resources Wales is an evidence based organisation. We seek to ensure that our strategy, decisions, operations and advice to Welsh Government and others are underpinned by sound and quality-assured evidence. We recognise that it is critically important to have a good understanding of our changing environment. We will realise this vision by: Maintaining and developing the technical specialist skills of our staff; Securing our data and information; Having a well resourced proactive programme of evidence work; Continuing to review and add to our evidence to ensure it is fit for the challenges facing us; and Communicating our evidence in an open and transparent way. This Evidence Report series serves as a record of work carried out or commissioned by Natural Resources Wales. It also helps us to share and promote use of our evidence by others and develop future collaborations. However, the views and recommendations presented in this report are not necessarily those of NRW and should, therefore, not be attributed to NRW. www.naturalresourcwww.naturalresourceswales.gov.ukeswales.gov.uk Page 2 Report series: NRW Evidence Reports Report number: 29 Publication date: July 2014 Contract number: R001233 Contractor: ENSIS Ltd. Environmental Change Research Centre, UCL, London. Contract Manager: Tristan Hatton-Ellis Title: Condition Assessment of Eight Standing Waters in Welsh Sites of Special Scientific Interest (SSSIs) Author(s): Goldsmith B., Shilland, E.M., Yang, H. Shilland. J., Salgado, J. & Turner, S.D. Technical Editor: Tristan Hatton-Ellis Peer Reviewer(s) Tristan Hatton-Ellis Approved By: Catherine Duigan Restrictions: None Distribution List (core) NRW Library, Bangor 2 National Library of Wales 1 British Library 1 Welsh Government Library 1 Scottish Natural Heritage Library 1 Natural England Library (Electronic Only) 1 Distribution List (others) John Ratcliffe, NRW Helen Millband, NRW Bob Edwards, NRW Jenny Higgins, NRW Mike Jenkins, NRW Rob Blacklidge, NRW Ian Hawkins, RSPB Graham Rutt, NRW Nicola Broadbridge, NRW Isobel Macho, Carmarthenshire County Council David Cowley, Cyngor Ynys Mon Adam Daniel, Cyngor Gwynedd Andrea Rowe, Vale of Glamorgan Council Ruth Hall, Natural England Jo-Anne Pitt, Environment Agency Recommended citation for this volume: B. Goldsmith, E.M. Shilland, H. Yang, J. Shilland, J. Salgado & S.D. Turner. 2014. Condition Assessment of Eight Standing Waters in Sites of Special Scientific Interest (SSSIs). NRW Evidence Report No: 29,147pp, Natural Resources Wales, Bangor www.naturalresourcwww.naturalresourceswales.gov.ukeswales.gov.uk Page 3 Blank page www.naturalresourcwww.naturalresourceswales.gov.ukeswales.gov.uk Page 4 Contents 1. Crynodeb Gweithredol ................................................................................................... 11 2. Executive Summary ....................................................................................................... 12 3. Introduction .................................................................................................................... 13 3.1. Background ..........................................................................................................................13 3.2. Aim of the Report .................................................................................................................13 4. Methods ........................................................................................................................ 15 4.1. Study sites ...........................................................................................................................15 4.2. Previous Data ......................................................................................................................15 4.3. Aquatic Macrophyte Surveys ...............................................................................................15 4.4. Mapping Aquatic Macrophytes ............................................................................................17 4.5. Physico-Chemical Survey ....................................................................................................17 4.6. Shoreline Development Indices (SDIs) and other lake data ................................................18 4.7. Palaeolimnological data .......................................................................................................19 4.7.1. Sediment core dating .......................................................................................................19 4.8. Bathymetric Survey ..............................................................................................................19 4.9. Interpretation of the attribute data and overall assessment of site condition ......................20 4.10. Total Phosphorus limits......................................................................................................22 4.11. Acidification environmental standards (ANC boundaries) .................................................24 4.12. Trophic scores (TRS and PLEX) .......................................................................................24 4.13. Changes to the CSM methods ...........................................................................................25 4.14. List of Abbreviations Used. ................................................................................................25 5. Site Condition Assessments .......................................................................................... 27 5.1. Pysgodlyn Mawr ...................................................................................................................27 5.1.1. Site description .................................................................................................................27 5.1.2. Condition Assessment and Discussion ............................................................................28 5.2. Llyn Llech Owain ..................................................................................................................41 5.2.1. Site description .................................................................................................................41 5.2.2. Condition Assessment and Discussion ............................................................................42 5.3. Llyn Pencarreg .....................................................................................................................55 5.3.1. Site description .................................................................................................................55 5.3.2. Condition Assessment and Discussion ............................................................................56 5.4. Witchett Pool ........................................................................................................................68 5.4.1. Site description .................................................................................................................68 5.4.2. Condition Assessment and Discussion ............................................................................69 5.5. Llyn Treflesg ........................................................................................................................81 5.5.1. Site description .................................................................................................................81 5.5.2. Condition Assessment and Discussion ............................................................................82 5.6. Llyn Cerrig-bach ...................................................................................................................95 5.6.1. Site description .................................................................................................................95 5.6.2. Condition Assessment and Discussion ............................................................................96 www.naturalresourcwww.naturalresourceswales.gov.ukeswales.gov.uk Page 5 5.7. Llyn Traffwll ........................................................................................................................106