Characterising Scotland's Marine Environment to Define Search Locations for New Marine Protected Areas
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Scottish Natural Heritage Commissioned Report No. 432 Characterising Scotland's marine environment to define search locations for new Marine Protected Areas Part 2: The identification of key geodiversity areas in Scottish waters COMMISSIONED REPORT Commissioned Report No. 432 Characterising Scotland's marine environment to define search locations for new Marine Protected Areas Part 2: The identification of key geodiversity areas in Scottish waters For further information on this report please contact: Ben James Scottish Natural Heritage Great Glen House Leachkin Road INVERNESS IV3 8NW Telephone: 01463 725235 E-mail: [email protected] This report should be quoted as: Brooks, A.J. Kenyon, N.H. Leslie, A., Long, D. & Gordon, J.E. 2013. Characterising Scotland's marine environment to define search locations for new Marine Protected Areas. Part 2: The identification of key geodiversity areas in Scottish waters. Scottish Natural Heritage Commissioned Report No. 432. This report, or any part of it, should not be reproduced without the permission of Scottish Natural Heritage. This permission will not be withheld unreasonably. The views expressed by the author(s) of this report should not be taken as the views and policies of Scottish Natural Heritage. © Scottish Natural Heritage 2013. COMMISSIONED REPORT Summary The identification of key geodiversity areas in Scottish waters Commissioned Report No. 432 Project no: 28877 Contractor: ABP Marine Environmental Research Ltd Year of publication: 2013 Background The Marine (Scotland) Act 2010 and the UK Marine and Coastal Access Act 2009 include new powers for Scottish Ministers to designate Marine Protected Areas (MPAs) in the seas around Scotland as part of a range of measures to manage and protect Scotland’s seas for current and future generations. Work to identify these MPAs is coordinated through the Scottish MPA Project, a joint project between Marine Scotland, Scottish Natural Heritage (SNH), the Joint Nature Conservation Committee (JNCC) and Historic Scotland. SNH and JNCC submitted formal advice to Scottish Ministers on the identification of Nature Conservation MPAs in Scotland’s seas in December 2012. On the 25 July 2013, the Scottish Government launched a 16-week consultation on the full suite of 33 possible Nature Conservation MPAs, noting that a further four MPA search locations remain to be fully evaluated. This report focuses on the identification of key geodiversity areas in Scottish waters, which helped determine the inclusion of proposed geodiversity protected features in the resulting suite of recommended Nature Conservation MPAs. Section 1 of this report outlines the background, aims and objectives of the work. Section 2 outlines the development of a methodology to prioritise key geodiversity areas in Scottish waters. This methodology is closely based on the Geological Conservation Review (GCR) scientific framework for the identification and prioritisation of important aspects of Earth heritage in the terrestrial environment. However, subtle amendments to the existing GCR methodology were introduced in order to ensure consistency with the Scottish MPA selection guidelines. These guidelines prioritise areas that: (i) contain key features; (ii) contain features considered to be under threat and / or subject to rapid decline; and/or (iii) are of functional significance for the overall health and diversity of Scottish Seas. Section 3 of this report provides details of the key geodiversity areas identified in Scottish waters. The list of key geodiversity areas was compiled using the GCR-style scientific framework and is based on expert judgement and the recommendations from a workshop in February 2010 attended by a range of leading Earth scientists with expertise in the Scottish marine environment. i Supporting statements and scientific justifications for the selection of the key geodiversity areas include summary literature reviews, overviews of data availability and lists of relevant publications. Main findings The Scottish sea bed is characterised by the presence of a wide range of geological and geomorphological features that are distributed across the shelf and deep-ocean environment. These structures and bedforms can be categorised into eight main themes or ‘blocks’. These are: o The Quaternary of Scotland; o Submarine Mass Movement; o Marine Geomorphology of the Scottish Deep Ocean Seabed; o Seabed Fluid and Gas Seep; o Cenozoic Structures of the Atlantic Margin; o Marine Geomorphology of the Scottish Shelf Seabed; o Coastal Geomorphology of Scotland; and o Biogenic Structures of the Scottish Seabed. A list of 35 key geodiversity areas on the Scottish seabed was identified from a database of previously identified geological and geomorphological seabed features. The list was compiled using a robust scientific methodology and expert judgement. Each of the key geodiversity areas belongs to one of the eight marine geodiversity blocks outlined above. The largest number of sites (11) falls within the Quaternary of Scotland block. This is perhaps unsurprising due to the diversity of features representing Scotland’s glacial legacy and their presence in each of the Scottish MPA regions. Overall, the key geodiversity areas are spread across all the Scottish MPA regions and both the Scottish shelf and deep ocean environment are equally well represented. Although a substantial amount of Scottish seabed mapping has been undertaken over the past few decades, there is some disparity in the level of detail of mapping of the geodiversity areas: for example, not all have had their seabed morphology assessed in detail using multibeam bathymetric survey techniques, and some lack supporting borehole data. These data gaps have (in certain cases) hindered interpretation and/or the delineation of the key geodiversity area boundaries. It is highly probable that future seabed mapping will reveal additional geodiversity interests considered to be of high conservation importance under the terms of the assessment methodology developed here. For further information on this project contact: Ben James, Scottish Natural Heritage, Great Glen House, Inverness, IV3 8NW. Tel: 01463 725235 For further information on the SNH Research & Technical Support Programme contact: Knowledge & Information Unit, Scottish Natural Heritage, Great Glen House, Inverness, IV3 8NW. Tel: 01463 725000 or [email protected] ii Table of Contents Page 1. INTRODUCTION ........................................................................................................... 1 1.1 The characterisation of Scotland's marine environment .................................. 1 1.2 Aims and objectives ........................................................................................ 1 1.3 Key terms ........................................................................................................ 3 1.4 Format of the report 3 2. METHODOLOGY .......................................................................................................... 5 2.1 Overview ......................................................................................................... 5 2.2 Background ..................................................................................................... 5 2.2.1 The geological conservation review scientific framework ................................ 5 2.2.2 Guidelines to assist the identification of Scottish marine protected areas ....... 6 2.3 A scientific framework for the prioritisation of key geodiversity areas ............. 7 2.3.1 Overview ......................................................................................................... 7 2.3.2 Key components .............................................................................................. 8 2.3.3 Selection of key geodiversity areas ................................................................. 9 2.3.4 The delineation of key geodiversity area boundaries .................................... 10 3. KEY GEODIVERSITY AREAS IN SCOTTISH WATERS ........................................... 11 3.1 Overview ....................................................................................................... 11 3.2 Block 1: Quaternary of Scotland .................................................................... 27 3.2.1 Summer Isles to Sula Sgeir Fan .................................................................... 28 3.2.2 Small Isles ..................................................................................................... 36 3.2.3 Loch Linnhe and Loch Etive .......................................................................... 41 3.2.4 West Shetland Margin palaeo-depositional system ....................................... 47 3.2.5 The Southern Trench .................................................................................... 53 3.2.6 Devil's Hole and Fladen Deeps ..................................................................... 58 3.2.7 Wee Bankie and Bosies Bank ....................................................................... 65 3.2.8 The North Sea Fan ........................................................................................ 70 3.2.9 The Barra Fan ............................................................................................... 76 3.3 Block 2: Submarine mass movement ............................................................ 83 3.3.1 Scottish Continental Slope slide complexes .................................................. 84 3.4 Block 3: Marine