Marine Biological Association of the United Kingdom Occasional Publication No. 14 Characterisation of the South West European Marine Sites Summary Report W.J. Langston∗1, B.S.Chesman1, G.R.Burt1, S.J. Hawkins1, J.Readman2 and P.Worsfold3 April 2003 A study carried out on behalf of the Environment Agency, Countryside Council for Wales and English Nature by the Plymouth Marine Science Partnership ∗ 1(and address for correspondence): Marine Biological Association, Citadel Hill, Plymouth PL1 2PB (email: [email protected]): 2Plymouth Marine Laboratory, Prospect Place, Plymouth; 3PERC, Plymouth University, Drakes Circus, Plymouth Titles in the current series of Site Characterisations Characterisation of the South West European Marine Sites: The Fal and Helford cSAC. Marine Biological Association of the United Kingdom occasional publication No. 8. pp 160. (April 2003) Characterisation of the South West European Marine Sites: Plymouth Sound and Estuaries cSAC, SPA. Marine Biological Association of the United Kingdom occasional publication No. 9. pp 202. (April 2003) Characterisation of the South West European Marine Sites: The Exe Estuary SPA Marine Biological Association of the United Kingdom occasional publication No. 10. pp 151. (April 2003) Characterisation of the South West European Marine Sites: Chesil and the Fleet cSAC, SPA. Marine Biological Association of the United Kingdom occasional publication No. 11. pp 154. (April 2003) Characterisation of the South West European Marine Sites: Poole Harbour SPA. Marine Biological Association of the United Kingdom occasional publication No. 12. pp 164 (April 2003) Characterisation of the South West European Marine Sites: The Severn Estuary pSAC, SPA. Marine Biological Association of the United Kingdom occasional publication No.13. pp 206. (April 2003) © 2003 by Marine Biological Association of the U.K., Plymouth, Devon All rights reserved. No part of this publication may be reproduced in any form or by any means without permission in writing from the Marine Biological Association. ii 1. EXECUTIVE SUMMARY The UK and EU have recently committed to an ecosystem-based approach to the management of our marine environment. In line with the requirements of the Habitats regulations, all consents likely to significantly affect Special Protection Areas (SPAs) and Special Areas of Conservation (SACs) are to be reviewed1. As part of this process, ‘site characterisation’ has now been accepted as an important requirement within the Environment Agency’s Review of Consents procedures, particularly with respect to complex systems such as estuaries. The current project, undertaken by the Plymouth Marine Science Partnership (PMSP), represents the first phase in this site characterisation – the collation and assessment of existing relevant information (up to 2002). Using published information and unpublished data-sets from regulatory agencies, conservation bodies and research institutes, evidence is compiled on the links between potentially harmful ‘activities’, environmental quality, and resultant biological consequences. The focus is on the effects of water and sediment quality on the key interest features of European Marine sites in the South West of England, namely: • Fal and Helford cSAC • Plymouth Sound and Estuaries cSAC/SPA • Severn Estuary pSAC/SPA • Poole Harbour SPA • Exe Estuary SPA • Chesil and the Fleet cSAC/ SPA Detailed analysis for each of these sites is provided individually, under separate cover (see page ii for full list of titles in this series). This summary report contains an overview of physical properties, uses and vulnerability for each of these sites, together with brief comparisons of pollution sources, chemical exposure (via sediment and water) and evidence of biological impact (from bioaccumulation to community-level response). Limitations of the data, and gaps in our understanding of these systems are highlighted and suggestions are put forward as to where future research and surveillance is most needed. Hopefully this may assist the statutory authorities in targeting future monitoring and remedial activities. 1 In England, a recent amendment to legislation allowed all candidate SAC’s to be treated (from 28th February 2000) as if they were European sites (enabling consents on these sites to be reviewed prior to the EU formally adopting the site) iii iv Plate 1. Some of the operations/activities which may cause disturbance or deterioration to key interest features of South West European Marine Sites (1) (2) (3) (4) (5) Diffuse sources of contaminants include rivers and streams (1), agricultural and road run-off (2-5). Point sources include discharge from industrial installations (6) and sewage treatment works (4 & 7) (6) (7) Photographs: 1, 3-7: Ian Britton, Freefoto.com 2: MBA v Plate 2. Some of the operations/activities which may cause disturbance or deterioration to key interest features of South West European Marine Sites (2) (3) (1-3) The continuing contribution from legal (and possible illegal) usage of TBT in antifouling, and the persistence of TBT in sediments implies a long-term hazard in some southwest marine sites. The impact of copper and zinc in antifoulants for commercial, military and leisure craft has (1) still to be evaluated in many areas. (4) (5) (7) (6) Many catchment areas in the southwest are highly mineralised and have a history of mining activity (4). Despite current treatment schemes (5), drainage channels and adits (6&7) and run-off from mine sites still impact on several of the southwest marine sites Phot ographs: 1, 2: Ian Britton, Freefoto.com. 3, 6, 7: MBA 4: Steve Johnson, Cyberheritage 5: Unipure Europe vi Plate 3. Some of the Interest Features and habitats of the South West European marine sites (1) (2) The Sea Lamprey Petromyzon marinus (1) and extensive subtidal reefs of the honeycomb worm Sabellaria alveolata (2) are found the Severn Estuary pSAC (3) Maerl biotopes such as Phymatolithon calcareum (3) in the Fal and Helford cSAC, are well recognised as having particularly rich and diverse communities and can be sensitive to changes in water quality (4) Chesil and the Fleet cSAC has a sizable population of a rare charophyte, the foxtail stonewort Lamprothamnium papulosum (4), which is sensitive to high levels of phosphate (5) (6) Allis shad Alosa alosa (6) is declining Avocet Recurvirostra avosetta (5) is one of throughout its range on the western coasts the Annex I bird species common to three of Europe, and is rare in the UK. The of the South West marine sites; Plymouth Tamar Estuary, Plymouth Sound and Sound and Estuaries, The Exe Estuary and Estuaries cSAC, is the only recently- Poole Harbour confirmed spawning site is in the UK. Photographs: 1: Erling Svensen 2&3: Keith Hiscock, MARLIN 4: Pietro Pavone, Dept. of Botany, University of Catania. 5: Eric Islay 6: Willy Van Cammeron vii Plate 4. Some of the Interest Features and habitats of the South West European marine sites (1) (2) Specialised flowering plant, the yellow-horned poppy Glaucium flavum (1) is part of the perennial vegetation of stony banks in Chesil and the Fleet cSAC. Shore dock Rumex rupestris (2) thought to be the world’s rarest dock and one of the rarest plants in Europe is an interest feature of the Fal and Helford cSAC. Common Tern Sterna (3) hirundo (3) in Poole (4) Harbour SPA, and the Slavonian Grebe (Podiceps auritus) (4) in the Exe Estuary SPA, are part of the internationally important populations of regularly occurring Annex 1 bird species. (5) (6) The Severn Estuary pSAC is considered Plymouth Sound and Estuaries cSAC to be one of the best areas in the UK for supports a significant presence of mudflats Atlantic salt meadows (Glauca- and sandflats not covered by seawater at low Puccinellietalia maritimae) (5) tide (6) Photographs: 1: Stan Beesley 2: Roger Mitchell, English Nature 3: Helen Baines 4: Keith Regan 5: English Nature (www.oursouthwest.com) 6: Cornwall Wildlife Trust viii CONTENTS 1. EXECUTIVE SUMMARY ................................................................................... iii 2. INTRODUCTION ...................................................................................................1 3. OBJECTIVES..........................................................................................................3 4. METHODOLOGY AND APPROACH ..................................................................5 5. CONSTRAINTS AND UNCERTAINTIES............................................................7 6. SITE CHARACTERISATIONS..............................................................................9 6.1 THE FAL AND HELFORD cSAC............................................................9 6.2 PLYMOUTH SOUND AND ESTUARIES cSAC, SPA.........................17 6.3 THE SEVERN ESTUARY pSAC, SPA..................................................27 6.4 POOLE HARBOUR SPA.......................................................................35 6.5 THE EXE ESTUARY SPA .....................................................................41 6.6 CHESIL AND THE FLEET cSAC, SPA ................................................47 7. CONCLUSIONS AND RECOMMENDATIONS ................................................55 8. ACKNOWLEDGEMENTS...................................................................................59 9. ANNEXES..............................................................................................................61 Annex 1. Combined Bibliography ..................................................................61 Annex 2. Conservation Features