Research Report No. 1293 Development of a marine and coastal enhancement project assessment framework for Scottish inshore waters

Introduction

1.1 Overview

Owing to the increasing number of marine and coastal habitat enhancement proposals being submitted to NatureScot, a project was commissioned in December 2020 to review existing case studies and guidance and use this to develop a marine and coastal enhancement project assessment framework for Scottish inshore waters. The work, as presented in this report, is focused on four species / habitats (referred to as features) that applicants most frequently propose as enhancement and restoration opportunities: native oysters, seagrass, saltmarsh and sand dunes. This project was led by GoBe Consultants Ltd (GoBe), with expert support from Heriot-Watt University (native oysters), UK Centre for Ecology and Hydrology (UKCEH) (saltmarsh and sand dunes) and Swansea University / Project Seagrass (seagrass).

1.2 Requirement For This Project

Leaving the environment in a better state than which we find it in, rather than simply conserving it as it is, has been a growing area of focus over the last decade. This approach has been supported across the world, initially by voluntary measures, and more recently with increasing legal frameworks for commitments and compliance (Section 2). This report builds on what was already provided through a growing voluntary movement promoting marine enhancement, for example by developers on specific projects. Overall, there is a general sense of ambition and environmental stewardship from communities and partnerships, Government and private sectors; and the realisation that environmental improvement may often provide a full circle feedback benefit to a range or sectors.

Many of the marine and coastal enhancement proposals submitted to NatureScot are novel and therefore require thorough consideration, including the evidence requirements to support them. They need to be able to demonstrate an understanding of the ecosystem dynamics, sensitivities and impacts in order to provide a robust baseline on which to develop a project. Proposals also raise regulatory challenges such as being located within protected areas or require more detailed consideration of planning legislation and frameworks. As a result, there are concerns that proposals looking to help enhance or restore habitats could be delayed where the existing environmental interactions and/or enhancement outcomes are not adequately detailed or considered and this, in turn, may impede their potential to succeed. Whilst certain guidance exists, from translocation protocols to individual species restoration guidance, as detailed in Section 3, none specifically encompass an enhancement framework for the range of habitats and species addressed by this project.

The present framework is now needed to set out a series of principles to help guide the assessment of proposals coming forward. This will ensure appropriate proposals can be supported and that early engagement with regulators and statutory bodies is encouraged.

NatureScot and other regulators also need to build on existing experience and current knowledge of the success of and lessons learned from marine and coastal enhancement projects. This will help to improve understanding of scheme feasibility and effectiveness and strengthen existing guidance and assessment frameworks. NatureScot wishes to draw out lessons learned in order to develop overarching guidance that will assist in the future with the provision of advice in this area.

Positive outcomes for marine enhancement proposals received by NatureScot can be optimised by providing an efficient, consistent, transparent and robust approach. This framework aims to guide those planning an enhancement project through the process, advising on the types of information required by NatureScot, other regulators and funding bodies, as well as what approaches are most likely to lead to success. Ultimately the framework provides a clear structure from which applicants may build their proposals and map out the necessary components to ensure an efficient process. This will in turn provide fair and consistent consideration across proposals and more readily provide the reality of successful enhancement. The provision and use of a consistent framework allows NatureScot to provide better advice, in a timely manner, ensure consistency between different projects, support site suitability assessments and in doing so improve the chances of success in enhancement projects. The framework can help to provide suitable guidance on project compliance and risks to ensure greater project efficiency and progression at the early stages.  Therefore a clear framework approach will improve the process for advice and assessment for NatureScot, applicants and relevant stakeholders.

The focus of proposed enhancement activities has recently been around native oyster and seagrass restoration, though NatureScot has also seen enquiries on cockles and saltmarsh habitat enhancement. There has also been a growing interest in connected activities including collection of broodstock for native oyster hatcheries, collection of seagrass seeds and setting up of hatcheries for native oysters and lobsters. Another area of growing interest is use of sand dune enhancement in coastal adaptation as a response to climate change, which is expected to be increasingly applied in the future.

This framework will target the four features that are expected to dominate future proposals namely: native oysters, seagrass beds, sand dunes and saltmarsh.

1.3 Aims

The three principle aims of the contract focused on the four species / habitats, are outlined below:

• Review: Draw up a list of marine and coastal enhancement projects / case studies and deliver a review of these and the lessons learned, as well as reviewing any other available guidance from elsewhere in temperate environments, outlining implications for Scotland.
• Framework: Develop an assessment framework for marine and coastal enhancement proposals, where they occur inside and outside protected areas.
• Recommendations: Identify further guidance and research required to inform and allow effective progression of marine and coastal enhancement proposals in Scotland.

1.3 Scope

As detailed above this project is concerned with marine and coastal habitat enhancement, for the four specific features detailed, but the review will include other types of environmental improvement to inform the framework, as defined within the terminology below in Table 1.

1.4 Approach

A review of current legislation, policy and regulation relevant to marine and coastal enhancement, and experience applying this to such schemes, was carried out based on Government sources and other scientific and grey literature, as well as consultation with key contacts (as detailed in Acknowledgements). The review also included wider guidance and frameworks to date, as well as specific case studies, both in Scotland and the rest of the UK / internationally, through a review of scientific publications and other grey literature. This has provided particular insight on best practice, the lessons learned and the rules by which some projects operate, as well as highlighting particular strengths and weaknesses in practice and assessment. Some of the primary considerations within the review have included:

• Existing practice;
• Novelty in proposals;
• Regulatory challenges both at site level and within wider regional frameworks;
• Guidance;
• Level of engagement and timing;
• Assessment guidance / principles; and
• Fit within or parallel to other frameworks / guidance.

This baseline review has informed the development of detailed tools to support the framework, justifying criteria and linking back to guidance or legislation where required. These are provided in a separate set of documents including:

• Guidance document; and
• Proposal form.

Current legislation, policy and regulation relevant to marine and coastal enhancement

2.1 International Drivers

Currently, there is global concern about the ongoing degradation of some coastal and marine environments and their supporting species / habitats in particular due to factors such as fishing, development, climate change, pollution and disease (IPBES, 2019). The Aichi Biodiversity Targets established by the United Nations (UN) Convention on Biological Diversity have a specific application within Scotland, including aims for the quality and quantity of wildlife to be improving and flourishing (targets 7, 9, 12, 13, and 14), in accordance with the UN 2030 Agenda for Sustainable Development. There are a rapidly growing number of related programmes that further support these targets (e.g. through the New Deal for Nature and UN Decade On Ecosystem Restoration) along with new strategies, including the Convention on Biological Diversity (CBD) Post-2020 Biodiversity Framework, which will be used to progress to the 2050 Vision of “Living in Harmony with Nature”. The OSPAR commission which aims to protect the North-East Atlantic included restorative targets in their 2010-2020 strategy, aiming to restore marine environments and biodiversity that have previously been adversely affected (it should be noted that the CBD and OSPAR are due to be updated through the COP and new North-East Atlantic Strategy). The Ramsar convention also supports restorative projects in wetland areas, a category they use widely to cover habitats including marshes, estuaries and near shore marine environments valuable to waterfowl. Furthermore, climate change conventions indirectly act as drivers towards enhancement. Habitats such as seagrass and saltmarsh have the potential for carbon draw down, with wetlands specifically included in carbon accounting according to the United Nations Framework Convention on Climate Change (UNFCCC) (IUCN Blue carbon).

2.2 Habitat Regulations

Under the Habitats Regulations (Conservation (Natural Habitats, &c.) Regulations 1994) all competent authorities must consider whether any plan or project will have a ‘likely significant effect’ on a European site (Special Areas of Conservation (SACs) and Special Protection Areas (SPAs)) and if so, an appropriate assessment should be undertaken (this process is referred to as Habitats Regulations Appraisal (HRA)).

NatureScot often provides advice to the relevant competent authority in assessing likely significant effects and must be consulted when an HRA is required. The Scottish Government provide advice sheets on HRA and development plan guidance. The advice sheets contain information on the use of simple mitigation measures, specific policies and caveats, and criteria-based policies within development plans. ‘The Habitats Regulation Appraisal of Plans Guidance for plan-making bodies in Scotland’ (NatureScot, 2015) notes under Stage 5 that there are cases where it is not likely that there will be a significant effect on a European Site, for example where a project or proposal is intended to protect the natural environment, including both the natural or historic environment, or for enhancement measures. However, if the introduction of a protected species affects a European site, an HRA must be completed by the Competent Authority using information provided by the applicant before any licence can be issued.

For marine SACs and SPAs NatureScot is responsible for producing management advice for each site. Each site is managed according to its conservation objectives in line with the requirements of the Habitats Regulations. Management plans may be developed by site or at a regional level. The format of the plan and the level of detail it contains is likely to vary between sites to reflect differences between protected features and location.

Monitoring of MPAs (including marine SACs and SPAs) is guided by the Scottish MPA Monitoring Strategy. Review of the condition of protected features forms part of this monitoring process and the results are used to inform future decisions on the management of sites.

For sea fisheries, management measures are implemented at a site level through the Inshore Fishing Act 1984 which may prohibit certain types of fishing activity (with either spatial or temporal zoning if appropriate).

2.3 UK Legislation and Regulation

2.3.1 Net Gain

The UK Environment Bill addresses the vision set out in the UK Government’s 25 Year Environment Plan with a specific requirement for 'net gain’. However, it should be noted that some of the Bill does not apply to Scotland, including Part 6 (nature and biodiversity); however, the Scottish Government conducted its consultation on environmental governance and principles and expects to address this in the UK Withdrawal from the European Union (Continuity) (Scotland) Act. The principle of net gain is the requirement for developments to increase habitat or ‘biodiversity net gain’ following operations and is supported by the Biodiversity Net Gain toolkit. After consultation, the latest version of the Environment Bill was released on 23 July 2019 with noted changes to the net gain policy. At the time of this repost publication (spring 2021), the legislation was undergoing scrutiny by the House of Commons and approaching its third reading. The policy has been tightened with a 10% net gain requirement confirmed in England (with a few exceptions) and for this to be maintained for at least 30 years. However, discussions within the UK Government are ongoing on the interaction between net gain and protected sites and the prevention of weakened site protection.

Current planning policy in the UK does account for biodiversity net gain, though this is not yet compulsory in the intertidal and marine areas (and with little standardisation of approach. Progress to date includes the development of matrices for biodiversity calculations, baseline assessment requirements, and consideration of potential benefits in the wider environment through these measures (ABPmer 2019). There is no metric currently to assess the marine environment. However, Natural England’s metric for intertidal habitats has been developed, informed by longer-term onshore metrics, in partnership with Imperial College London and Defra. V3.0 is due in spring 2021 with consultation gaining further input from various organisations such as the Seabed User and Developer Group (SUDG), Renewables UK and GoBe Ltd.

The metric provides a means to determine the extent of habitats required to compensate loss due to development, determined through various calculations including biodiversity and supported by guidance on intertidal habitats and connectivity. It covers a list of habitats, which includes coastal saltmarsh, littoral sediments dominated by aquatic angiosperms and littoral biogenic reefs including those made by native oysters (it does not include sand dunes as they occur above the mean high-water mark). This metric expands on that provided through the UK Habitat Classification, now providing a greater number of habitats and tackling challenges specific to the intertidal environment, e.g. difficulty to establish boundaries for dynamic intertidal environments and use of habitat buffer zones based on predicted movement. However not all temporal changes can be accommodated by the model such as tidal cycles, wave energy and sediment dynamics, therefore causing some risk to the success of a scheme.

2.4 Marine Legislation and Regulation in Scotland

Within Scottish legislation (Marine (Scotland) Act 2010) and policies (e.g. Scotland’s National Marine Plan (Scottish Government, 2015)) there is a commitment to the protection of marine habitats as well as for its sustainable enhancement and restoration. A summary of the legislation impacting on practice in Scotland is summarised below.

2.4.1 Marine planning

The Marine (Scotland) Act 2010 has a three-tier approach to the marine planning system, which covers the use of Scottish waters at regional, national and international level (UK Marine Policy Statement). Scotland’s National Marine Plan (2015), currently subject to review, provides the framework for managing all development, activities and interests in and/or affecting the marine area, including conservation and ecosystem services. The National Marine Plan also states the contribution of Marine Protected Areas (MPAs) and other designated areas to the protection and enhancement of a region. General Policy 9 (National Heritage) of the National Marine Plan requires that development and use of the marine environment must: (a) Comply with legal requirements for protected areas and protected species; (b) Not result in a significant impact on the national status of Priority Marine Features (PMFs); and (c) Protect and, where appropriate, enhance the health of the marine area. Further information is detailed in ANNEX 1: Scotland’s National Marine Plan in regard to Enhancement and Restoration.

There are also eleven Scottish Marine Regions where the aim is to develop regional marine plans led by Marine Planning Partnerships in line with the National Marine Plan. These have so far been developed for Shetland and the Clyde.

The Clyde Marine Plan, for example, aims to ensure that the Marine Protected Area (MPA) network contributes to the protection and enhancement of the Region; that there are opportunities identified for environmental enhancement; and that those activities and development do not significantly impact PMFs. This can be managed via a Marine Licence and Town and Country Planning determination processes, including reference to Local Biodiversity Action Plans and Reports (Clyde Marine Planning Partnership, 2019).

2.4.2 Marine licensing

Marine Scotland Licensing Operations Team (MS-LOT) is the lead regulatory authority in relation to marine licensing and consenting and Marine Scotland Compliance for the monitoring and enforcement of marine and fishing laws and reporting to prosecuting authorities. Marine licences are issued by MS-LOT under the Marine (Scotland) Act 2010 (inshore region, between 0 and 12 nm) and under the Marine and Coastal Act 2009 (offshore region, between 12 and 200 nm). The Scottish Government (2015) note a marine licence is required for several activities including, but not limited to:

• Depositing any substance or object within the Scottish marine area, either in the sea or on or under the seabed, from a vehicle, vessel, aircraft or marine structure. This includes beach replenishment below Mean High Water Springs (MHWS).
• Constructing, altering or improving any works within the Scottish marine area either in or over the sea or on or under the seabed. This applies to removing or adding substrate to the seabed such as shell fragments or stones (e.g. ‘cultch’ for native oyster restoration, also see Section on Biosecurity) as this changes the particle size of the underlying sediment.
• Using a vehicle, vessel, aircraft, marine structure or floating container to remove any substance or object from the seabed within the Scottish marine area.
• Carrying out any form of dredging within the Scottish marine area (this includes whether or not removing any material from the sea / seabed).

Permission is required from Crown Estate Scotland (CES) for use of the foreshore and seabed. The following activities will require either a lease, licence or consent from CES:

• Aquaculture and seaweed cultivation;
• Wild seaweed harvesting on Crown-owned foreshore
• Coastal protection and flood defence works;
• Dredging and dumping material from, and onto, the seabed;
• Filming on the foreshore;
• Laying of moorings;
• Deployment of research equipment; and
• Seabed investigation work e.g. grab samples to inform research / activities (see Crown Estate Scotland information on marine works).

2.4.3 Relationship between marine and terrestrial licensing

Whilst the terrestrial licensing system is detailed in the following sections, there are arrangements made between the terrestrial and marine licensing systems where the two systems overlap. Marine licensing covers the marine area up to MHWS and terrestrial planning control extends down to Mean Low Water Springs (MLWS); therefore there is an overlap of consenting regimes in the inter-tidal zone. However, for some activities, this overlap extends out to or out to 12 nm, i.e. for fin fish farming (Scottish Government, 2015). Some activities therefore may need both a marine licence and planning permission. In such cases, early engagement with the consenting authorities is even more of a priority to determine which consents are required. These arrangements ensure consistency in detail on how one impacts the other, both for overlapping areas and those adjacent to each other, e.g. liaison between authorities, consistency in proposals, timing and sharing of the evidence base.

2.4.4 Nature Conservation Marine Protected Area (MPA) management

There is a duty on public authorities under the Marine (Scotland) Act 2010 to ensure that their activities and consenting decisions do not hinder the conservation objectives of a Nature Conservation MPA. To aid policy and decision-makers, Marine Scotland created the Nature Conservation MPA management handbook that provides guidance on how the management needs of Nature Conservation MPAs (MPA) will be assessed and how any required measures will be developed and implemented [reference]. The handbook also describes the duty of public authorities in relation to MPAs and provides policy guidance on compliance. Marine Scotland is responsible for the designation and management of MPAs. NatureScot is responsible for producing management advice for each site. Each site is managed according to its conservation objectives in line with the requirements of the Marine (Scotland) Act 2010. Management plans may be developed by site or at a regional level. The format of the plan and the level of detail it contains is likely to vary between MPAs to reflect differences between protected features and location.

Monitoring of MPAs is guided by the Scottish MPA Monitoring Strategy, created by Marine Scotland, NatureScot and JNCC. Review of the condition of protected features forms part of this monitoring process and the results are used to inform future decisions on the management of NCMPAs.

Management measures may be put in place by Marine Scotland, depending on the sensitivity of the features and the site’s conservation objectives. Regulators such as MS-LOT or local authorities may consult with NatureScot before issuing licences or permits to ensure that the activity will not hinder the site’s conservation objectives, other than insignificantly. This is referred to as an assessment under Section 82 or Section 83 of the Marine (Scotland) Act 2010. For sea fisheries, management measures are implemented at a site level through Marine Conservation Orders which may prohibit certain types of fishing activity (with either spatial or temporal zoning if appropriate).

The Joint Nature Conservation Committee (JNCC) and NatureScot have roles in providing nature conservation advice to Scottish Ministers, on monitoring protected features and assessing the success of management measures and the wider MPA network. NatureScot has a statutory remit to ensure any scheme is compliant with the Wildlife and Countryside Act 1981.

2.4.5 Priority Marine Features (PMFs) management

Scotland’s National Marine Plan supports the concept of and policy protection for PMFs. The 81 PMFs adopted by Scottish Ministers in 2014 are species and habitats that were identified as the basis for focussing marine conservation work in Scotland . The PMF list includes three of the features identified by this framework: native oysters, seagrass beds and intertidal mudflats, i.e. including habitat for saltmarsh (coastal sand dunes and saltmarsh are addressed by terrestrial features). The PMF existing designations checklist (summary table for consultation) provides applicants with the various national and international legislation applicable for each feature, i.e. Habitats Directive, Wildlife & Countryside Act, Convention on International Trade in Endangered Species (CITES), Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) threatened and/or declining habitats and species, Biodiversity Action Plan (BAP) priority habitat/species (i.e. sand dunes) and International Union for Conservation of Nature (IUCN) Global Red list status. This is supported by a suite of PMF guidance documents including a checklist form regarding impacts on PMFs from development / activities.

2.5 Terrestrial Legislation and Regulation in Scotland

The policies and principles found in the National Planning Framework and the Scottish Planning Policy set out how the Scottish Government expect Planning Authorities to address national issues, such as coastal change, in Strategic Development Plans and their regional-scale Local Development Plans.

2.5.1 Terrestrial planning

Planning authorities in Scotland have a duty under the Climate Change (Scotland) Act 2009 to deliver the Scottish Climate Change Adaptation Programme, which addresses the risks set out in the Climate Change Risk Assessment (Scotland) including erosion and flooding risks to the natural environment, infrastructure, people and built environment and business.

Both the Flood Risk Management (Scotland) Act 2009 and the Coast Protection Act 1949 provide the legislative background to coastal management in Scotland. The Coast Protection Act aims to prevent erosion and encroachment by the sea whereas the Flood Risk Management (Scotland) Act deals with flood bodies in Scotland so in effect, they are implemented together. The Coastal Protections Act 1949 (part I) empowers Local Authorities with coastlines to carry out protection works inside and outside their area subject to approval from Marine Scotland (maintenance of existing works only).

Scottish Environment Protection Agency (SEPA) is the authority responsible for flood risk management and for implementing the Flood Risk Management (Scotland) Act 2009. Shoreline Management Plans (SMP) have been produced for only short sections of the Scottish coast: Local Authorities include Angus, Dumfries & Galloway, East Lothian, Fife and Ayrshire. SMP are the over-arching management approach to each stretch of coastline agreed by local authorities, the local communities and other interested parties. Local authorities also have powers (but not obligations) under the Coast Protection Act 1949 to protect the land from the sea.

As noted above, terrestrial planning authorities (Strategic and Local Planning Authorities and National Park Authorities) are responsible for all terrestrial planning matters down to MLWS and for marine fish farming (finfish and shellfish) where planning consent is required out to 12 nm (Scottish Government, 2015). In the intertidal zone, between MLWS and MHWS, the terrestrial planning authority overlaps with Marine Scotland's responsibilities for the marine area. As a result, marine and terrestrial planning authorities should consult one another formally during plan preparation.

Some Local Development Plans have identified needs for enhancement of both the environment and natural heritage, for example, Aberdeen City Council (2017). This highlights the need for Natural Riparian Buffer Strips to be created for the protection and enhancement of water bodies and local biodiversity, including lochs, ponds, wetlands, rivers, tributaries, estuaries and the sea. It also identifies a need for the protection and enhancement of natural heritage outwith designated sites (in proportion to the opportunities available), with specific aims to enhance biodiversity through the creation and restoration of habitats and, where possible, incorporating existing habitats (Aberdeen City Council, 2017).

Scottish Borders Council, together with stakeholders, has taken further measures to promote enhancement through the development of a biodiversity offset scheme that accounts for the residual environmental impacts of developments (e.g. renewables) in upland species / habitats, including blanket bog (Scottish Borders Council, 2017). The implementation of eight such schemes has allowed biodiversity improvements to be mainstreamed into the planning process by seeking biodiversity benefits at the landscape scale, whilst simultaneously benefiting ecosystem services. These include flood protection, water quality, carbon storage (woodland, grassland and bog habitats) and recreation (game and fisheries management) (see RSPB Planning naturally). Negotiations with farmers and landowners have balanced their needs with those of biodiversity and flood protection gains.

2.5.2 Terrestrial licensing

The Coast Protection Act 1949 (part I) enables Local Authorities with coastlines to conduct coastal protection works under licence inside and outside their jurisdiction as necessary, with approval from Marine Scotland. Proposed schemes, other than maintenance or emergency operations, must be advertised by the Coast Protection Authority and a notice of works served upon a number of bodies, including NatureScot and SEPA.

Depending on the nature and scale of a scheme proposed by either Local Authorities or individuals, planning permission may be required under the Town and Country Planning (Scotland) Act 1997, where the proposal extends above the MLWS mark. Permission of the landowner will also need to be acquired prior to the commencement of the scheme.

Under the Planning etc (Scotland) Act 2006, SEPA assist the Scottish Government. SEPA provide advice to Marine Scotland and the applicant when enhancement or restoration works result in the relocation of sand / shingle to restore beach levels. To safeguard against pollution for marine ecology interests, the applicant should refer to SEPA’s Pollution Prevention Guidelines and SEPAs standing advice on marine licence consultations. Authorisation under the Water Environment (Controlled Activities) (Scotland) Regulations 2005 from SEPA may also be required. Enacting environmental enhancement may also fall under the Flood Risk Management (Scotland) Act 2009 which requires SEPA to ensure that flood risk management is undertaken sustainably (see Marine Scotland advice on coastal erosion and flood risk management).

Other considerations to be taken when considering land for enhancement include protections around wild land which should be safeguarded as part of the planning application (Scottish Planning Policy, 2020). Also, should woodland removal be necessary as part of enhancement this should occur in line with UK Forestry Standards and should be included in the planning application to the relevant authority (Forestry Commission Scotland, 2009). For woodland removal permitted under the Forestry Act 1967, legal enforcement of the actions required to implement a change in land use will normally be based on felling licence conditions.

2.5.3 Protected Areas

The Nature Conservation (Scotland) Act 2004 (as amended) requires all public bodies to further the conservation of biodiversity. This resulted in the production of a Scottish Biodiversity List which identifies species considered by Scottish Ministers, to be of principal importance for biodiversity conservation in Scotland and informs the conservation process. This informs the statutory designation of Sites of Special Scientific Interest (SSSI) made by NatureScot. For any applications within an SSSI, applicants (the landowner or occupier – see NatureScot guidance for land managers) must apply to NatureScot for consent to carry out certain operations as set out in the Operations Requiring Consent (ORC) list for that SSSI and application form, which is also available from Sitelink. This will be assessed by NatureScot operations officers with advice from specialists as necessary.

The Wildlife and Natural Environment (Scotland) Act 2011 provides additional wildlife and habitat protection, along with management of non-native species and sets out biodiversity duties including restoration. The Act provides the means for management of invasive non-native species (INNS) in Scotland, including a code of practice, and enables licences for protected species to be granted for any social, economic or environmental purpose, under the Wildlife and Countryside Act 1981.

2.5.4 Terrestrial features management

Planning Authorities, and all public bodies under Section 2 of the Nature Conservation (Scotland) Act 2004, have a duty to further the conservation of biodiversity and this must be reflected in development plans and development management decisions. Coastal sand dunes and saltmarsh are a UK BAP Priority Habitat along with Annex I of the Habitats Directive 1992 and the Wildlife & Countryside Act 1981.

2.6 Current practice within NatureScot

The number of marine and coastal enhancement proposals received by NatureScot has increased over the past 18 to 24 months. NatureScot advises on proposals in line with NatureScot’s statutory duties, with each proposal treated in a similar but ad-hoc approach. Due to this notable increase, NatureScot drafted an initial internal note to define guidance for responses to marine habitat enhancement queries, including pathways and contacts within NatureScot, guidance used / referred to and primary case studies for each habitat (NatureScot, 2020b). Whilst the aspects relating to individual habitats are captured in the following chapters, the overarching pathways to processing proposals currently are provided in Figure 1. As illustrated in the figure, this current provisional framework calls particularly for:

• Early engagement with regulators;
• Information required;
• Need for biosecurity measures;
• Use of guidance from the Scottish Code for Translocations and NatureScot published guidance documents;
• If within a Special Area of Conservation (SAC) or Special Protection Area (SPA), then need for HRA under the Conservation (Natural Habitats & c.) Regulations 1994 (as amended), for NCMPAs assessment under Section 82 or 83 of the Marine (Scotland) Act 2010 or SSSI consent may be required if an SSSI could be affected; and
• Circumstances required for a PMF checklist to be completed.

Proposals have mostly been handled on a case-by-case basis to date, with a combination of local operations officers  and species and habitat specialists receiving and dealing with proposals. However, as enhancement projects have grown in volume, there has been a range of specific issues identified within the process. These include:

• Proposal volume: Staff capacity at NatureScot as the volume of proposals increase and there is a resulting need to make efficiencies internally as well as fair and consistent assessment across all proposals.
• Proposal complexity: There is a current move towards more complex projects e.g. with multi-species / trophic proposals and the need to involve multiple staff and teams.
• Enquiry process: Enquiries are direct to specialist advisors or via operations officers.. There is a need for consistent advice across all staff.
• Applicant’s organisational structure: Multiple organisations / individuals enquiring about one site.
• Applicant’s formal obligations: Applicants unclear on contacts and teams at relevant organisations, e.g. Marine Scotland, Crown Estate Scotland, NatureScot, SEPA and the relevant Local Authority; as well as the licensing process and variables requiring consideration, e.g. location / conflicts, scale, links to resources, e.g. biosecurity and other species-specific requirements.

These different aspects and challenges are addressed by the new framework being proposed as part of this work. NatureScot note an iterative process of engagement is required with the applicant, firstly encouraging pre-application engagement followed by a review of the full proposal and steer depending on its nature; second providing advice depending on the consenting process triggered; and thirdly engagement with the relevant parts of Marine Scotland.

OVERVIEW OF THE FOLLOWING FEATURE-SPECIFIC SECTIONS

4.1 Introduction

Whilst the framework developed as an output of this project is designed to be relevant to all habitats and relevant species, a review of each of the four specific features focussed on in this project has been carried out in the following sections. The following sections provide a review of the commonalities in practice on the ground, guidance, lessons learned and recommendations to build on the framework.

Each section provides an overview of the types of schemes and context, followed by a review of all projects in Scotland, as well as a selection of others in the wider UK and internationally. Each section is completed with a review of the primary management measures in place, guidance and conclusions providing an appraisal of lessons learned and best practice.

A list of selected projects of interest of relevance to these four features is provided in ANNEX 3: Case Study Inventory (though note this is not a complete list). A detailed review of lessons learned from a selection of these features, both in Scotland and the UK / internationally, is provided in ANNEX 4: Detailed Case Study Review.

5. NATIVE OYSTERS

5.1 Overview

European native oyster enhancement / restoration has been one of the largest and longest-running focus areas of the four features within this project, with approximately two new schemes per year. Scotland is considered to be the leading country involved in native oyster restoration, outside of mainland Europe. Enquiries to NatureScot are mainly focused on restoring native oyster populations or collecting broodstock for hatchery production. The main driver is restoration rather than enhancement because of the historical widespread extirpation of oysters in Scottish waters and throughout Europe (e.g. Fariñas-Franco et al., 2018a; Pogoda et al., 2019; 2020a). Most proposals to date aim to increase biodiversity, with economic benefit often being a long-term objective. Restoration of the historical beds on the East coast of Scotland requires translocation of native oysters, whereas those on the West coast have been proposed on existing remnant habitats. Overall, practice is based on natural habitats / species and their historical environmental range, with an emphasis on strengthening existing populations. However, each project is unique, complex and hard to characterise to a particular ‘type’. All projects are at different stages of development, offering a range of lessons learned that are relevant to this study.

Schemes are developed by either a partnership of existing organisations, including public sector, private, academia and NGOs; else they are community-driven. However, community-driven schemes are a relatively new concept over the last few years and are often brought to life through local active engagement in marine conservation, with the community actively seeking projects. Native oyster enhancement / restoration is a particularly good ‘fit’ for local communities because they are perceived as more feasible and attractive to funders.

5.2 Projects

NatureScot has been directly involved in five native oyster restoration schemes, as detailed below.

5.2.1 Scotland

The Dornoch Environmental Enhancement Project (DEEP) is an ongoing project focused on restoring native oysters in the Dornoch Firth, initially using oyster cages on the seafloor and more recently with oysters laid on shell cultch ‘mini-reefs’. DEEP is a collaborative project between the Glenmorangie Company, Heriot-Watt University, and the Marine Conservation Society (MCS). DEEP is the most significant and longest-running project (since 2013) with the largest engagement and subsequent scope for learning. The scheme has benefited from a thorough translocation protocol, clear objectives and identified mechanisms for consenting, offering a good model for future projects. In the developmental stages, the project obtained Planning Permission from the Local Authority classed legally as an Aquaculture Production Business to enable exclusive rights to the areas where restoration was pioneered. The project has also obtained Marine Licences from MS-LOT to allow shell and oyster deposits to the seabed. NatureScot, Marine Scotland, FHI are engaged to provide advice to the project teams. The DEEP project is located within the Dornoch Firth and Morrich More SAC, the Dornoch Firth and Loch Fleet SPA and SSSI and adjacent to the Moray Firth SAC. In order to move to a fully ‘operational’ scale, the DEEP team are currently being guided through the Habitats Regulation Appraisal, planning, licensing and consenting process with Marine Scotland, the FHI, Highland Council and NatureScot to scale up the project and lay oysters and shell directly on the seabed over several hectares. DEEP has produced a Biosecurity Plan for translocation. The present marine licenses technically require all materials to be removed from the site by end of 2022. Future ‘Operational’ scale restoration is likely to require a licence for construction, through the Marine Licence, from Marine Scotland to enable the restored habitat to be left in place.

The Wild Oysters Project is a three-year restoration project launched in June 2020 and developed as part of a collaboration between the Zoological Society of London (ZSL), BLUE and British Marine. The project is based in three locations around the UK; the Firth of Clyde, Scotland (Inner Clyde Estuary SPA); Conwy Bay, Wales (Menai Strait and Conwy Bay/ Y Fenai a Bae Conwy SAC); and Tyne and Wear, England (Northumbria Coast SPA). The aim of the Wild Oysters Project is for the UK seas to have a self-sustaining population of native oysters, which will provide clean water, healthy fisheries and enriched biodiversity. At each location, the project is building local partnerships, including the Clyde Porpoise Community Interest Company, Bangor University and Groundwork North East. At each hub, oyster nurseries will be installed with caged oysters suspended under marinas along with seabed restoration, which will include baseline surveys and cultch deployment. In the Firth of Clyde, the proposal to suspend oyster cages from the marina / pier was supported by BLUE. The proposal and the route to engagement were through the Local Authority to check planning permission. However, a marine licence for construction / new infrastructure was not required, as the suspended cages were attached to existing infrastructure. The project registered with FHI as an aquaculture business.

The Loch Craignish Native Oyster Restoration Project in Argyll was led by the Scottish charity Seawilding and funded by the National Lottery from 2019. The project has also partnered with local volunteer association Craignish Restoration of Marine and Coastal Habitat (CROMACH), the Ardfern Yacht Centre, Heart of Argyll Wildlife Organisation, as well as Stirling University’s Institute of Aquaculture and the Scottish Association of Marine Sciences (SAMS). The project aims to reintroduce a population of native oysters; monitor the oysters’ potential for wild spawning and the future restoration of the native oyster stocks, and enable a sustainable community-owned fishery. The project aims to grow 1 million oysters in a floating nursery at Loch Craignish and to translocate the oysters to suitable pre-surveyed sea-bed sites around the loch, where they will be monitored. All juvenile native oysters are sourced from Morecambe Bay Hatchery. No additional cultch has been required as there is an abundance of cockle, oyster and horse mussel shells on the seabed. The project has secured a marine licence and has worked with NatureScot to ensure that biosecurity protocols are followed.

Other oyster restoration projects that Nature Scot are aware of being planned in Scotland include those in the Firth of Forth and Loch Ryan. The organisations involved include WWF, Royal Botanical Garden Edinburgh (RBGE), Heriot-Watt University and local community groups. In March 2021, the Lochaline Native Oyster Project, in the Sound of Mull launched, founding the Community Association of Lochs and Sounds (CAOLAS). Also planned are the Plockton (Lochalsh) and Wester Ross scheme.

5.2.2 UK

NatureScot has engagement with the UK & Ireland Native Oyster Restoration Network and the Native Oyster Restoration Alliance (NORA), both of which are currently developing significant guidance through their communities. Due to Scotland’s leading role in native oyster restoration, this project has not drawn further on case studies listed in the rest of the UK in ANNEX 3: Case Study Inventory.

5.2.3 International

In Europe, the Netherlands has particularly advanced enhancement projects underway, though these differ from Scottish projects because in some cases the species were not originally in those locations. Enhancement projects are well advanced in France, the Netherlands and Germany, with both the Netherlands and Germany demonstrating experience with native oyster translocation. The knowledge gained from these schemes was inputted into the NORA European Guidelines on Biosecurity in Native Oyster Restoration (zu Ermgassen, et al., 2020a). Experience of oyster restoration, albeit using different species, in America is also notable through the Nature Conservancy NGO. The Chesapeake Bay Foundation (CBF) oyster restoration projects in Maryland and Virginia are considered the longest and largest-scaled restoration projects in America (see ANNEX 4: Detailed Case Study Review).

5.2.4 Projects Related to Other Relevant Features

Experience with other bivalve species has been gathered where there are gaps specific to native oysters. DEEP considered subtidal horse mussel (Modiolus modiolus) habitat as a reference ecosystem to inform native oyster reef restoration (Fariñas-Franco et al., 2018b). Horse mussel reefs are protected in Strangford Lough, Northern Ireland but were partially destroyed in the 1990s resulting in the introduction of a no-take zone in 2011, protecting the remaining horse mussel habitat. In 2005 the Modiolus Restoration Plan was developed to restore horse mussel biogenic reefs to favourable conservation status. Surveys and restoration research that was conducted on natural and restoration sites within Strangford Lough included the use of acoustic substrate mapping, benthic grabs, video tows and diver photo quadrats (Fariñas-Franco et al., 2014, 2018; Geraldi et al., 2014).

The Wadden Sea Plan 1997 contained a trilateral policy and management plan for blue mussel (Mytilus edulis) fisheries aiming for an increase of the total area and more natural development and distribution of intertidal blue mussel beds. To protect and achieve an increase in the area of intertidal blue mussel beds, the entire intertidal area in the Dutch Wadden Sea was permanently closed for blue mussel fisheries in 2004. The prohibition of mussel fishery in the intertidal areas should allow natural development of blue mussel beds, however, this has enabled the spread of the Pacific oyster (Crassostrea gigas) after its introduction by humans in the 1970s (Folmer et al., 2017). The likely spread of the Pacific oyster is further amplified by climate change which is predicted to significantly increase the reproductive range in UK waters (King et al., 2020).

5.3 Management

5.3.1 Consenting and Policy

Oyster restoration is a relatively new field in Europe compared with other nations such as the US, and therefore management and policy measures may require adaption to develop a suitable best practice and policy framework, that reflect the needs of oyster restoration projects (zu Ermgassen et al., 2020a).

In Scotland, native oysters are Royal Shellfish and property of the Crown. Consent to exploit was previously required from CES. However, since 2017 this consent has passed to Marine Scotland but there is no specific licence applicable to native oysters. Overall, the licensing process is as follows:

• Local Authority for the acquisition of planning permission;
• Marine Scotland for various licensing through the Conservation, FHI or MS-LOT teams (as appropriate); and
• NatureScot for licence concerning translocation to areas of former historical oyster beds.

Native oysters are a PMF and they are regarded as being one of the most sensitive PMFs to the impacts of seabed disturbance. The conservation objectives for native oysters in Loch Sween NCMPA are to ‘conserve’ native oysters. Currently, the MPA network in Scotland is considered adequate for native oysters as on the basis of existing evidence it has not been possible to achieve replication of the feature within the network but if additional areas of importance are identified in the future these could be considered as additional MPAs (Cunningham et al., 2015). Native oysters are also protected by other mechanisms including OSPAR threatened and declining species list (Region II) and UK Biodiversity Action Priority Species list, and in Scotland are included on the Scottish Biodiversity List and the NatureScot Action Framework (2007). Whilst protection against fishing activities is provided at some designated sites, e.g. Dornoch Firth SPA, SAC and SSSI where the DEEP project is located, alternative protection measures may be required in other locations. However, at present, there is a tension between the underlying aims of the Habitats Directive to “maintain or restore” and the required HRA process that mechanically seeks to establish the impact of restoration on present-day conservation features in SACs, with a view to establishing no adverse impact on site integrity (see Fariñas‐Franco et al., 2018).

5.3.2 Biosecurity

Some of the major barriers to progressing native oyster restoration in Europe are the risks of disease, often through aquaculture operations (e.g. Marteilia refringens, Bonamia ostreae and B. exitiosa) and invasive species (e.g. slipper limpet (Crepidula fornicata) or Pacific oyster (Crassostrea gigas)). Such risks result from the introduction / translocation of oysters or cultch, i.e. repurposing old shells for use as a settling medium. However, strong biosecurity measures, reinforced by scientific understanding of the vectors of disease and INNS, can be incorporated at both the project planning (specifically site selection) and operation stages; this is key to safeguarding existing disease and INNS-free oyster populations (zu Ermgassen et al., 2020a).

Such measures may include chemical and mechanical cleaning of shell and quarantine; depuration (purification) (zu Ermgassen et al., 2020a; CREW, 2019); and molecular screening for harmful pathogens. For example, molecular screening of M. refringens, B. ostreae and Ostreid herpesvirus-1, all listed under EU legislation, has been carried out by the Marine Scotland Science Disease Diagnostic group on behalf of DEEP. Recent studies have also suggested the use of non-lethal diagnostic techniques based on environmental DNA (eDNA) to detect and quantify B.osterae DNA in seawater (Mérou et al., 2020; von Gersdorff Jørgensen et al., 2020). With this new method, B. ostreae may be detected by only sampling water from the environment of isolated oysters or isolated oyster populations. This non-lethal diagnostic eDNA method could have the potential for future surveys and oyster breeding programs aiming at producing disease-free oysters (von Gersdorff Jørgensen et al., 2020).

Translocation of native oysters (and cultch material) must be supported by a Biosecurity Plan submitted to NatureScot and Marine Scotland; and, if the restoration scheme is classified under an aquaculture business, then the Biosecurity Plan must be available to the FHI. Further guidelines are provided by The European Native Oyster Habitat Restoration Handbook (Preston et al., 2020) and The European Guidelines on Biosecurity in Native Oyster Restoration (zu Ermgassen, 2020a), based on current knowledge and experiences. Along with setting out legal requirements, these documents recommend that projects apply a “Precautionary Approach” to prevent harm caused by accidental or poorly considered transfers, supported by a list of considerations on whether to proceed with translocation and if proceeding, then how to prepare adult oysters for translocation. The guidance also aims to provide those seeking to purchase stock from a hatchery with the information required to understand the biosecurity issues relating to hatcheries and assist those seeking to establish their own hatcheries in understanding the associated biosecurity requirement (zu Ermgassen et al., 2020a).

It is important to realise that no translocation is entirely risk-free and there are no testing methods that are 100% reliable at detection at present. For this and other reasons, disease outbreaks can still occur and INNS is a high-risk factor since it is not covered by FHI statutory regulations, as advised by Marine Scotland and Recent Scottish Government FHI’s epidemiological investigations at Lochnell Oysters, the Dornoch Firth and the Loch Craignish Native Oyster Restoration Project are testament to this. The presence of the parasite B. ostreae in consignments of native oyster have resulted in culling at the Orkney Shellfish Hatchery (OSH) Ltd and Heriot-Watt University. Within Bonamia-infected areas, techniques should be sought to take advantage of any disease tolerance that has developed in broodstock from high disease load areas, without transferring pathogens; and from reference to the listed potential pathogens relevant to European waters (Preston et al., 2020).

5.3.3 Genetics

The Berlin Oyster Recommendations, (Pogoda et al., 2019) state the importance of preserving the genetic diversity of European native oyster populations in order to maintain the species’ ability to adapt to changing environmental conditions, disease and climate change. This in turn will aid the long-term survival of native oyster habitats. The recommendations (Pogoda et al., 2019) also suggest establishing new hatcheries and spatting ponds for the production of robust and genetically diverse oyster seed, to eliminate the need for bringing in stock, with protocols adapted to preserve the existing genetic integrity of the population.

Understanding whether the potential donor source population is not only genetically distinct but also adapted to their local environment is needed (zu Ermgassen et al., 2020b). The management of genetic diversity of restored populations is of high importance to avoid inbreeding and ensure long‐term adaptability (Lallias et al., 2010). It is important that restoration practices, at a minimum, maintain local or regional genetic diversity and adaptations. Furthermore, restoration projects should seek to utilise breeding techniques that maximise the genetic diversity in the offspring to enable resilience to future change (Preston et al., 2020). Lallias et al. (2010) suggest high genetic diversity and bonamiosis-resistance are important features of any sustainable restoration programme. The European Native Oyster Restoration Handbook (Preston et al., 2020) notes that if the restoration area contains diseases such as Bonamia, then the program should seek to use locally sourced broodstock to utilise genetic resistance and adaptations.

Genetic variation and disease tolerance were further highlighted at the 2021 NORA Genetics workshop (25/02/2021), where the importance of geneticists in restoration schemes was noted, for providing advice on how to improve / prevent inbreeding in hatcheries and spatting ponds, as well as estimating the genetic variation of the source material and the restored population.

5.4 Guidance

A review of the primary guidance to inform the enhancement of native oyster habitats is provided below.

5.4.1 Scotland

In earlier years, guidance was provided by the Species Action Framework before any native oyster-specific guidance was available. However, NatureScot and Marine Scotland are currently working together on developing a new set of native oyster guidance, specific to the Scottish context (both environment / species and regulation), including learning from recent projects in particular. This will be finalised once the legal and policy framework / consenting approach is fully developed. The guidance will form part of a forthcoming native oyster restoration best practice guidance package for Scottish waters that will be published on NatureScot and Marine Scotland’s websites. It will aim to provide advice to would-be applicants and ongoing schemes already in development, including both specific on-site guidance as well as wider geographic considerations.

5.4.2 UK

Much of the other guidance on oyster restoration and enhancement has stemmed from the key associations below:

• The ZSL and the University of Portsmouth jointly run the Native Oyster Network which includes organisations from UK and Ireland. The network was established in 2018 and includes academics, conservationists, oyster fisheries and NGOs who are working to restore self-sustaining populations of the native oyster.
• The European Native Oyster Restoration Alliance (NORA) was established during an international workshop on native oyster restoration hosted by the German Federal Agency for Nature Conservation (BfN) and the Alfred Wegener Institute (AWI) in Berlin in November 2017. NORA was consolidated by the second international meeting in Edinburgh 2019, supported by DEEP partners and Nature Scot. This ongoing European network aims to reinforce and restore native European oysters. Its members include representatives of Government agencies, Universities, NGOs, consultancies and oyster growers.

5.4.3 International

Numerous guidelines for undertaking oyster restoration exist and have been invaluable in the early phases of European oyster restoration, such as identifying suitable cultch material (zu Ermgassen et al., 2019).

The European Native Oyster Habitat Restoration Handbook (Preston et al., 2020) for the UK and Ireland was funded by the LIFE Programme of the European Union and the Environment Agency (with NatureScot on the Steering Committee). Recognised as supporting the goals of the UN Decade on Ecosystem Restoration (2021-2030) it is planned to be one of four handbooks to be produced, with others covering seagrass and saltmarsh restoration, however, these have yet to be published. The handbook provides foundational and practical guidance on the restoration and conservation of both native oysters and native oyster habitats across the UK and Ireland. This includes planning, permitting, licensing, funding, deployment, project techniques, biosecurity risks and public engagement. This publication was written as a native oyster specific annexe to the Restoration Guidelines for Shellfish Reefs (Fitzsimons et al., 2019), providing a detailed overview of information relevant to the restoration of the European native oyster, whilst adhering to international standards of ecological restoration. The handbook recommends goal-based project planning in order to provide a framework whilst ensuring the best chance of achieving the highest level of recovery possible. The handbook also recommends a project feasibility study to establish whether the location is suitable for ecosystem restoration i.e. historical populations of native oyster and determining threats to a project including pollution and fishing; and establishing a reference or target ecosystem; as well as examples of deployment options, benefits of each and points to consider. Detailed consideration of MPAs, fisheries, other key stakeholders to involve and project funding are recommended. However, the examples provided within the Handbook are predominately English based with minimal input of Scottish issues, such as the difference in legislation.

The European Guidelines on Biosecurity in Native Oyster Restoration (zu Ermgassen et al., 2020a) was funded by the LIFE Programme of the European Union and the Environment Agency, with input from NatureScot. This guidance provides an introduction to working with relevant authorities to ensure restoration work exceeds the mandatory requirements. The handbook notes biosecurity is an integrated part of restoration as it is a pathway for INNS and disease, and highlights the importance of working with local communities to understand risks. The handbook also provides biosecurity guidelines in relation to native oyster and clutch translocation, with the following recommendations:

• Do not consider donor sites outside historical native range;
• Do not consider donor sites with high-risk INNS or diseases that are not present at the restoration site;
• Minimise the physical distance between the donor and the restoration site; and
• Avoid movement across latitudinal gradients.

However, these documents are generic, European-based and they do not address local jurisdiction issues (although, case studies of specific projects are provided in the guidance documents). For example, in a Scottish context, it is more important to avoid translocation between semi-isolated waterbodies, which has proven to be a significant issue. Crossing of latitudinal gradients is less of an issue in Scotland as many organisms are free to move and spread their larvae and progeny up and down the latitudinal gradients of, for example, the west coast.

A list of recommendations that the participants and members of NORA agreed upon are detailed in the Berlin Oyster Recommendations. They provide a foundation to support European countries in implementing commitments under the Habitats Directive, the Marine Strategy Framework Directive and OSPAR recommendations (Pogoda et al., 2019). The recommendations highlight the importance of protecting sites where native oysters are not only abundant but in areas where they were previously recorded or are present but of low density. Recommendations are:

1. Produce sufficient oysters for the restoration of oyster reefs. This should be undertaken by supporting existing hatcheries, spatting ponds and spat collector techniques or support the establishment of new ones.
2. Identify and create suitable sites for the restoration of oyster reefs. This can be undertaken by identifying sufficient undisturbed and suitable areas for the restoration and protection of native oysters in all regions of its historical range. This includes the restoration of a suitable substrate in some areas.
3. Provide suitable substrate for successful recruitment. The extraction of native oyster shells from the marine environment for other uses should be prohibited. The availability of suitable substrates, such as shells, will maximise larvae recruitment.
4. Respect Bonamia-free areas. Encourage research on the Bonamia parasite and infection dynamics. Biosecurity protocols must be strictly followed in Bonamia-free areas.
5. Create common monitoring protocols which will provide comparable results for projects throughout Europe. Where possible, monitoring should include the assessment of ecosystem services on a habitat and ecosystem scale.
6. Preserve genetic diversity of native oysters in Europe by adapting established hatchery and pond production protocols.

The Restoration Guidelines for Shellfish Reefs (Fitzsimons et al., 2019) provides both guidance in decision-making for establishing shellfish reef restoration projects and examples of different approaches undertaken by experienced practitioners in a variety of geographic, environmental and social settings. It also provides a high-level checklist to help guide assessments and links to relevant chapters within the guidance, including establishing a feasibility plan including alternative design considerations, identifying funding sources, as well as undertaking monitoring, evaluation and reporting. These guidelines update and expand on the Practitioners Guide (Brumbaugh et al., 2006) (which primarily focuses on supporting community-based restoration efforts in the USA), capitalising on the improvements in knowledge around the ecological function of bivalves in their coastal environments as well as the depth and breadth of experience that now exists globally. The guidelines were produced by and for practitioners, managers and community members involved in shellfish restoration globally, with the main objective of simplifying complex scientific principles and terminology into a resource that would be useful to a broad audience (Fitzsimons et al., 2020). However, the permitting section largely focuses on the USA and the target oyster species are ecologically and functionally a little different to the predominantly subtidal Ostrea edulis.

5.5 Appraisal of Lessons Learned to Inform Framework

Whilst a detailed review of lessons learned from case studies is provided in ANNEX 4: Detailed Case Study Review, highlights raised in guidance material and strategic reviews specific to native oysters are detailed below.

5.5.1 Site selection

This is dependent on the individual requirements of native oysters, with an ultimate goal to identify sites where restoration measures are most likely to succeed. The selection of suitable sites is of fundamental importance, as it influences the survival, growth, fitness, reproduction, and recruitment of the species and will determine the success of the whole restoration project (Kerckhof et al., 2018; Laing et al., 2005). These reasons have driven a number of feasibility studies, as for BLUE prior to mounting oyster nurseries on offshore wind farms, whereby it was found that the abiotic factors in their chosen location were sub-optimal (Robertson et al., 2021). Site selection is initially defined through ecology history and distribution, the feasibility of restoration and the quality of environmental conditions (Farinas-Franco et al. 2018; Pogoda et al., 2020b). As a result, historical species presence is often cited as one of the key aspects of site selection, such as Borkum Reef Ground Oyster Pilot Project, where 30% of the Dutch North Sea floor was identified as suitable for shellfish reefs. In addition, species distribution models are valuable to inform distributions of known associated species, in order to assist with identifying potentially suitable sites where species-specific data is absent (zu Ermgassen et al., 2020b). While it is useful to learn from national and international examples, it is also essential to consider how these may need to be adapted for application to a specific region or site. A significant effort may be required to establish feasibility at a site such as DEEP (Fariñas‐Franco et al., 2018), which carried out archaeological and historical research to demonstrate the former presence of the native oyster at the site in the Dornoch Firth.

5.5.2 Evidence base

Consideration of gaps in knowledge must be addressed after the initial feasibility assessment before full-scale restoration, e.g. development of pilot studies, further research and adaptive management principles (Fitzsimons et al., 2019). For example, DEEP undertook testing and monitoring the suitability of the site (every six months), with a smaller number of oysters (300 in total) before scaling up in increments. Additionally, in the Netherlands, the Borkum Reef Ground Oyster Pilot Project findings influenced and led to the undertaking of the Haringvliet Dream Fund Project.

5.5.3 Regulation

Due to the low levels of experience, close and clear collaboration with the relevant authorities is vital in supporting the development of regulatory frameworks and overcoming existing barriers (Fitzsimmons et al., 2019) and this may incur significant project costs (human / financial resources). For example, there is not yet a framework in place in Scotland that specifically enables restoration activities and some phases of the DEEP project have therefore required the use of aquaculture legislation.

5.5.4 Management

Fitzsimons et al. (2019) highlight the importance of planning and setting restoration goals, with Preston et al. (2020) providing examples of deployment options, benefits of each and points to consider, information on project planning, permitting, licensing and funding; and illustrates a typical project timeline for native oyster restoration

The development of tools are highlighted in the literature, for example, using a checklist to guide the development of the methodology and feasibility studies (Fitzsimons et al., 2019), the use of a decision-making flow diagram to assist in planning and feasibility (Preston et al., 2020) and the use of the ‘Ecological Recovery Wheel’ to convey the progress of the ecosystem attributes compared to the baseline (Fitzsimons et al., 2019; Preston et al., 2020). The Recovery Wheel conveys the progress of the ecosystem attributes compared to the baseline, as adapted from the Society for Ecological Restoration’s International Principles and Standards for the Practice of Ecological Restoration (Gann et al. 2019) (SER Standards).

Due to the low levels of experience, science and tools, measures need to be adapted to develop appropriate best practices relevant to the needs of a project, with validation of the efficacy of the scheme actions being assessed on a case-by-case basis (zu Ermgassen et al., 2019). An example of this is demonstrated by the U.S. Army Corps of Engineers (USACE), which undertook additional investigations into the costs and benefits of sanctuaries and harvest reserves on the Maryland and Virginia Oyster Restoration Project (USACE, 2012). This assessment determined whether these practices were the most suitable for the area in terms of ecological and economic benefits, as such management measures had not been addressed previously in that region. It identified that the establishment of harvest reserves within proximity of sanctuaries could provide near-term support to the seafood industry and establish a diverse network of oyster resources for the Maryland and Virginia Oyster Restoration Project (USACE, 2012). Moreover, management of disease and INNS can be a challenge, particularly in sourcing biosecure stocks of native oysters. This has had big implications for DEEP when Bonamia was introduced to the Dornoch Firth. As a result, the lack of available biosecure stock has halted project plans for several months.

5.5.5 Monitoring

At the time of writing, NORA and the Native Oyster Network (NON) guidance on monitoring oyster restoration is expected to be published shortly.

5.5.6 Engagement

Successful communication to stakeholders is noted as important, particularly ensuring traditional owners (for North America) and local industry are included early in communication planning as key partners and audiences for most projects (Fitzsimons et al., 2019). Early involvement has been demonstrated to be effective, e.g. DEEP which has engaged with the local community and provided regular updates to agencies government on the project. Potential engagement tools should be considered, such as educational outreach, websites, social media and newsletters (Preston et al., 2020). It is also important for projects to work with and educate the local community particularly on the potential spread of INNS and pathogens (Fitzsimons et al., 2019; zu Ermgassen, 2020). For example, the Maryland and Virginia Oyster Restoration Project and the Loch Craignish Native Oyster Restoration Project, utilised the community in the restoration program, by setting up workshops to educate the public and to involve them in hands-on restoration and citizen science. Moreover, Fitzsimmons et al. (2019) acknowledge that clear communication with the permitting organisation and policymakers is vital in supporting the development of frameworks and overcoming existing barriers.

Pogoda et al. (2019) also review the NORA guidance and the Berlin Oyster Recommendations^. as detailed above and note the importance of maintaining communication within the NORA community to help advance the topics critical to developing oyster habitat restoration in Europe. Similarly maintaining communication with other shellfish restoration networks worldwide will be beneficial where valuable lessons can be learnt. One such example of communication, within Britain, is the Wild Oyster Project which reintroduced oysters across Britain and to do so drew on the Solent Oyster Restoration Project methodology and the Essex Native Oyster Restoration Initiative.

5.5.7 Benefits

Fitzsimons et al. (2020) and zu Ermgassen et al. (2020c) both note potential impacts on ecosystem functions and services as a result of enhancement / restoration projects such as an increase in biodiversity, fish biomass, or water quality. These benefits are noted in the objectives of the Loch Craignish Native Oyster Restoration Project alongside the primary goal of restoring native oyster beds, to additionally improve the water quality following degradation by scallop dredging, fish farming and recreation.

5.5.8 Risks

In relation to pathogens, the literature notes that for Bonamia-infected areas, techniques should be sought to take advantage of any disease tolerance that has developed in broodstock from high disease load areas, without transferring pathogens. Preston et al. (2020) list potential pathogens relevant to European waters and detail the importance of biosecurity as part of good restoration practice. zu Ermgassen et al. (2020a) detail the main routes of disease transmission in hatcheries and the requirement of a Biosecurity Plan in order to ensure that any restoration efforts in European waters are carried out responsibly.

In Scotland, climatic events may damage restoration projects, e.g. due to stochastic rainfall events causing freshwater and associated wastewater stress. Also, hot and cold spells may cause mortality in intertidal populations. For this reason, restoration projects should give some consideration to planning for resilience in this context. However, this is generally not relevant to Scotland where oyster restoration schemes are generally subtidal.

Restoration projects often rely on multiple sources of funding, some of which may not be in place at the onset of the project. This can provide difficulties fully specifying projects and can limits MS-LOT, NatureScot and other stakeholders ability to provide advice and guidance such as for licensing by MS-LOT, NatureScot and other stakeholders late consultation with competent authorities to ensure statutory obligations are being met (and the project costs of doing so).

Oyster restoration is still in its infancy in Europe, and policy and management measures need to be adapted to develop appropriate biosecurity ‘best practice’ (zu Ermgassen et al., 2019). There are gaps in knowledge and research and no method that ensures 100% absolute biosecurity within translocations schemes (and may never do) (zu Ermgassen et al., 2020a). Pogoda et al. (2019) note the importance of considering the risk posed by B. ostreae and avoiding further spread. NORA also strongly encourage this. Developing research to understand both the mechanisms of Bonamia tolerance / resistance, and ways in which scaling up the production of tolerant / resistant native oyster spat for restoration purposes has also been identified and is of high importance (Sas, et al., 2019). It is therefore critical that project managers work with the relevant authorities to develop appropriate best practice protocols in each case, and that validation of the efficacy of the actions undertaken are assessed on a case-by-case basis.

Genetic diversity and Bonamia resistance planning are important features of any responsible programme for the restoration of native oysters. Hatchery-produced populations from small numbers of brood stock have shown loss of genetic diversity relative to wild populations (Lallias et al., 2010). Moreover, native oyster numbers are so low, that in recruitment-limited environments there are insufficient mature oysters to allow the population to increase naturally (CREW, 2019; Fitzsimmons et al., 2020). It can therefore be a challenge to use locally sourced brood stock to build genetic resistance and resilience. A waterbody with a greater disease designation than the hatchery location should not be considered as a potential source of brood stock (zu Ermgassen, 2020b).

SEAGRASS

6.1 Overview

Seagrass restoration and enhancement is a fast-maturing discipline with examples of restoration and enhancement projects being implemented in a number of locations including the US, New Zealand, Australia and more recently in Europe (Tan et al., 2020; Brode et al., 2004; Moksnes et al., 2021). With such growing interest, studies have examined the effectiveness of a range of scales and methods of seagrass restoration across the world (van Katwijk et al., 2009). Recent high profile examples of wide-ranging success have been seen in the US where over 3000 ha of seagrass have been planted and brought to maturity in the Chesapeake Bay, leading to full ecosystem service recovery (Orth et al., 2020).

Whilst knowledge gaps remain, there is a growing body of evidence to support the development of effective restoration and enhancement projects, and key advice available in terms of ecological feedbacks and appropriate planning through the use of modelling. Over the past 20 – 30 years there have been several success stories on the east coast of the US, as well as smaller schemes in New Zealand, that can be used to inform and develop strategies to maximise efficacy. Whilst evidence gaps remain, the existing knowledge and experience of restoration projects and associated processes and technology published in the academic literature are considered a major strength for informing future programmes. In addition, the recent funding award from the Sustainable Management of UK Marine Resources (SMMR) Strategic Priorities Fund for the ‘Restoration of Seagrass for Ocean Wealth’ (ReSOW UK) project will help to address these evidence gaps. The ReSOW project (2021-2024) will facilitate informed management and restoration of seagrass for sustainable social, environmental and economic net gains for the UK.

Whilst initial seagrass enhancement proposals (and therefore guidance) in Scotland has been focused on seed collection, enquiries to NatureScot have recently grown in regard to larger and more varied seagrass restoration / enhancement projects. To date, no experimental seagrass restoration work has been undertaken other than one experimental trial of intertidal planting (Wilkie, 2009). This lack of science focus on seagrass restoration mirrors a wider knowledge gap around the biodiversity, functioning, monitoring and conservation of seagrass throughout Scotland. There is also evidence of historic loss of seagrass around Scotland (Cleator, 1993; Thomas, 2020; Green et al., 2021a), providing an opportunity for environmental renewal.

6.2 Projects

NatureScot are aware of several early-stage projects and proposals in Scotland, as detailed below, but there are no schemes already in place.

6.2.1 Scotland

Current seagrass restoration proposals in Scotland include those around the Firth of Forth and Solway Firth both at very early stages. There is also interest from several community groups to develop projects, e.g. around the Isle of Arran and in Wester Ross . A community-led seagrass restoration project in Loch Craignish is underway with support from the Biodiversity Challenge Fund in collaboration with the SAMS and Project Seagrass.

In addition, small-scale intertidal seagrass transplantation was trialled in the Tay Estuary for Zostera noltii. However only two out of the five plots were successful, two years after planting, with conclusions drawn that both elevation and hydrodynamic conditions of the receiving site must be similar to those of the donor site for success (Wilkie, 2009). It is likely that such experiments did not consider the suitability of the habitat and environment for those plants to survive.

Project Seagrass have explored the potential for a restoration project in Scottish waters, guided by a site selection process by NatureScot to scope out suitable (and unsuitable) sites, both for collection of seeds and consideration for potential restoration trials at these sites. NatureScot are working with Project Seagrass and other organisations to fill knowledge gaps around existing seagrass distribution, extent and bed characteristics which are required before strategic prioritisation of efforts into restoration activities can take place, and to inform seagrass restoration advice and guidance. For example, a seagrass genetics project is being carried out in collaboration with the RBGE to understand the genetic connectivity of existing beds; and thus the provenance of seeds in order to help determine the suitability of seed relocations.

Project Seagrass and Swansea University have recently completed building a Scotland wide seagrass habitat suitability model. This uses an ensemble approach and is driven by the use of known data points correlated against spatial environmental datasets. It is also understood that the JNCC are using a similar approach to model seagrass habitat suitability. The Project Seagrass study has shown the power of developing local scale detailed wave models to drive the models and the need for improved spatial datasets on existing seagrass. At Edinburgh University recent postgraduate research has included habitat suitability modelling around the Isle of Skye and the development of a regional and international framework for evaluating effective seagrass management and conservation. Recent studies by Project Seagrass and Heriot-Watt University have examined the current and historic distribution of seagrass in the Firth of Forth, documenting multiple potential areas of decline.

At Heriot-Watt University, postgraduate research has focussed on the distribution of intertidal seagrass species in the Firth of Forth and qualitative assessment of their persistence. Also, an assessment of the status and distribution of Zostera marina in Scotland was conducted by an Eden Project Learning student in collaboration with the University of Plymouth. Further research proposals and developments with academic partners may support Scotland-specific evidence and method development / guidance.

6.2.2 UK

To date, there has been limited seagrass restoration on the ground in the UK. Some studies were conducted in the 1970s using transplantation of seagrass ‘sods’ (Ranwell et al. 1974). The work of Swansea University and Project Seagrass was the first to progress and in 2013 trials were started to develop locally appropriate seagrass restoration methods building on the work of Prof Bob Orth and his team in the Chesapeake Bay (US). Comparative studies using transplants of shoots, transplants of seagrass ‘sods’ and seeds were conducted in West Wales alongside widespread trails (over multiple locations) with seeds. Restoration using seeds was found to be the most effective, primarily driven by the European green crab (Carcinus maenas) tearing apart the transplanted plant material. Trials of planting seagrass seeds continued resulting in a range of studies for which an initial study has been published (Unsworth et al., 2019).

Seagrass Ocean Rescue project ran between 2019 and March 2021 and was led by Project Seagrass in partnership with Sky Ocean Rescue, University of Swansea, World Wide Fund for Nature (WWF) and Pembrokeshire Coastal Forum in Dale Bay Pembrokeshire, Wales. The project planned to restore seagrass in a small experimental 2 ha area and aimed to inspire future major projects in other regions to restore the UK’s seagrass meadows. To date, the project has successfully planted 1.2 million Z. marina seeds, with thousands of mature plants recorded throughout the restoration area. The project has noted that germination has been a lot slower than hoped with some small patches performing poorly as a result of the necessity to store seeds due to extended community consultation. Some of the seeds (400 thousand) were planted in autumn 2020 with the expectation of improved germination due to the fresh planting of viable seeds. Work will now focus on monitoring with expectations of the habitat reaching maturity over a five-year period.

Swansea University and Project Seagrass are continuing work on method development on seagrass restoration. This includes the aquaria planting of seeds, studies on seed storage and a range of studies on different types of planting methods; this included a failed attempt to utilise biodegradable plastic mesh to support seagrass restoration in West Wales (see Mimicry of emergent traits amplifies coastal restoration success). Project Seagrass are currently in the early stages of developing a seagrass nursery as a commercial collaboration with Salix Bioengineering to help facilitate seagrass restoration across the wider UK.

Although limited planting has yet to be undertaken, the Ocean Conservation Trust in Plymouth are developing seagrass restoration planting plans under the REMEDIES programme, but no information has been publicly shared about progress. Other planned projects are being considered in the Humber and the Tees estuaries.

6.2.3 International Experience

Z. marina is extensive throughout the Northern hemisphere and so examples can be sought in multiple continents. For example, the German and Dutch are particularly advanced in seagrass restoration / enhancement, as well as USA. The Submerged Aquatic Vegetation (SAV) Program on the Eastern Shore, Virginia, USA, is considered a leading exemplar of how restoration can be conducted. This large-scale project has aligned decades of research on the biology of restoration with active restoration programmes. This has been focused on restoring the seagrass (Z. marina) habitat but also monitored the effect of this restoration on the surrounding ecosystem (Orth et al., 2020). The program included a large-scale seed restoration effort, where 74.5 million seeds were collected using hand and mechanised methods. These were broadcast into 536 individual restoration plots totalling 213ha. The areas have expanded since and so far resulted in a total of 3,612 ha of the vegetated bottom, from virtually no coverage before the restoration. The combined efforts by academic, non-profit and citizen groups stand as a beacon of hope for how Scotland can restore the extensive historic loss of seagrass. It is one of the more successful marine restorations for seagrasses and rivals other large-scale marine restorations in terms of scope, rapidity, dedication, and organisation. Orth et al. (2020) state the success of this restoration stems from several sources: directly from the large-scale seeding efforts over time and indirectly through positive feedbacks that promoted resilience and recovery.

6.2.4 Relevant Projects Focused on Other Features

Experience gained from other similar habitats / species was not considered for seagrass since sufficient experience was available that related specifically to this feature.

6.3 Management

6.3.1 Consenting and Policy

Seagrass restoration (of Zostera) is considered in its infancy in the UK compared with other nations, such as the US and several nations in Europe (e.g. Sweden, and the Netherlands) and in Scotland, limited restoration progress has been made. As a result, management and policy measures require adaptation to develop appropriate best practice guidelines and a policy framework that reflects the requirements of seagrass restoration / enhancement projects in Scotland. As a proposed Nature-based Solution (NbS) to climate change policy, the process within the devolved governments of the UK to support restoration is presently not fit for purpose. More information on seagrass extent and distribution would help inform future restoration projects.

In Scotland, seagrasses are a PMF, a UK BAP habitat, an OSPAR threatened and declining habitat and are listed under Annex I of the Habitats Directive. Currently, seagrass beds are protected in 30 MPA locations around Scotland (see the 2018 report to the Scottish Parliament on the MPA network). The marine licensing regime provided under section 21(1) (item 6) of the Marine (Scotland) Act 2010, may regulate the removal of seagrass in those cases where a vehicle, vessel, aircraft, marine structure or floating container is used to remove the seagrass from the seabed. Marine Scotland highlighted that applicants must provide an assessment of the effects of their proposed activity in support of their application. This may involve the collection of baseline data and studies to assess the effects (see Scottish Government strategic environmental assessment of wild seaweed harvesting). However, proposals will be considered on a case-by-case basis. As previously noted, any activity on the seabed will require a lease from CES. However, it should be noted that a lease would likely be considered on a case-by-case basis, with large scale projects potentially requiring a licence. Both NatureScot and MS-LOT should be contacted within the early stages of any proposal to ensure all options have been considered. If a project is considered exempt, an exemption form may be required; and part of the process would include evidence that the applicant has been in contact with NatureScot to assess the biodiversity implications (e.g. if in a protected / designated area). Licencing may also depend on any structures onshore (e.g. seed container / growing facility) and any potential discharge to the sea etc.

6.3.2 Biosecurity

Biosecurity is a recognised risk in seagrass restoration schemes, particularly with respect to the transplanting of plants and also through seed planting. Seeds at Swansea University have been washed in fresh seawater and low concentration of hydrogen peroxide to reduce the presence of associated organisms. Biosecurity is a fundamental element of proposal consideration and biosecurity planning needs to consider best practices for enhancement / restoration. Natural Resource Wales (NRW) required Seagrass Ocean Rescue to treat / sterilise all seagrass seeds prior to placement to prevent the colonisation of INNS species in Dale Bay (see Seagrass Ocean Rescue Project FAQ) however this practice could potentially be detrimental to the seagrass microbiome that likely travels with the seeds. Practice around seed translocation varies between the devolved nations. For England and Wales, there is some movement of seeds between sites due to existing data indicating limited genetic population variability between sites. Work is underway in Scotland to assess the population genetics of existing beds and determine whether translocation would negatively impact the existing diversity (comms. Dr Richard Lilley). Therefore, practices vary between projects from no or little consideration, through to sterilisation of all seeds before planting on a new site, as carried out by Project Seagrass. Outside of the UK, there has been some examination on the movement of seedling e.g. Denmark and Sweden, but no specific records of mechanisms to reduce biosecurity risk have been found. However, the risk is somewhat reduced as a result of donor and recovery sites often being located close together to allow for easy transfer.

6.3.3 Genetics

Experimental evidence on the resilience of seagrass systems indicates that enhanced genetic variability benefits resilience. Given the continued low levels of genetic variability found within English and Welsh meadows and the known extensive loss of UK seagrass, it is likely that isolated populations do now possibly exist and the enhancement of their genetic diversity will be important for the continuing resilience of seagrass in the face of a changing climate. Initial indications from the genetics studies being conducted by the RBGE indicate that some isolated populations may exist but these are limited. This work will be important to place Scottish seagrass in context with previous assessment of local genetic structure and connectivity of Zostera marina in northern Europe (Martínez-García et al, 2021).

Impacts on genetic diversity and connectivity during seagrass schemes may result from translocation, e.g. from east to west coast Scotland; as well as certain activities on-site, e.g. recreation, altering the natural genetics. However, Kendrick et al. (2012) note that genetic differences between seagrass populations (e.g. Z. marina and Z. noltii) showed limited differences regionally. Ecological studies of Z. marina in the US recorded genetic differences between intertidal and subtidal zones and between the False and Padilla Bays (Ruckelhaus, 1998), with effective migration of seed dispersal between the two bays (14 km apart). The importance of using local gene pools has been highlighted by Olsen et al. (2013), with genetic differentiation between Z. marina populations six times higher between Norwegian fjords than within fjords. However, Reynolds et al. (2012) suggest seagrass restoration that achieves high levels of genetic diversity will be more successful and will create more resilient seagrass ecosystems where plants survive longer, reproduce more rapidly, more quickly increase in density, and provide more ecosystem services. This is also supported by van Katwijk et al. (2009), which states that suitable gene characteristics for long-term survival can be achieved by transplanting genetically diverse donor material to be able to adapt to environmental changes and avoid inbreeding.

6.4 Guidance

A review of the primary guidance to inform the enhancement of seagrass habitats is provided below.

6.4.1 Scotland

The Scottish Code for Conservation Translocation is the framework upon which seagrass restoration proposals have been assessed to date, whether proposals are for seeds to be planted or adult plants transplanted. However new guidance is in development for seagrass restoration and enhancement in Scotland, forming the most advanced Scotland specific guidelines out of the four targeted features within this project. Much of NatureScot’s work has been informed by a recent Swedish handbook on the ecological, political and economic background for restoration (Moksnes et al., 2021) which was translated into English to inform seagrass restoration activities in the UK and beyond. NatureScot has since developed a Scotland seagrass restoration handbook and guidance document in collaboration with Marine Scotland and Project Seagrass (in draft, aim to publish 2021). With a focus on subtidal habitats, this aims to provide background information, regulatory considerations and monitoring / research guidance in one place to ensure projects are evidence-led (suitable location, method etc.). It also addresses evidence gaps on e.g. habitat suitability, genetics and biosecurity. NatureScot has also started to monitor physical parameters at seagrass beds around Scotland (e.g. temperature and light) to help guide site suitability requirements.

6.4.2 UK

UK wide guidance is currently being developed by the Environment Agency, ZSL and Portsmouth University (contracted to bring guidance together) with NatureScot, Swansea University and Project Seagrass engaged in the process amongst others.

6.4.3 International

NatureScot does currently advise some applicants to consider EU guidance, e.g. concerning areas of variability in a project. As noted above, there is a lot of technical information on seagrass restoration / guidance in Sweden and as a result, the handbook (Moksnes et al., 2021). However, whilst the guidance recommends transplanting adult plants, a UK seed-based method has been developed since the publication of the Swedish guidance. The main difference when considering the Swedish manual with regards to Scottish projects is concerned with genetics and policy, otherwise, it is the same species and much of the guidance is applicable.

6.5 Appraisal of Lessons Learned to Inform Framework

Whilst a detailed review of lessons learned from case studies is provided in ANNEX 4: Detailed Case Study Review, highlights raised in guidance material and strategic reviews specific to seagrass are listed below.

6.5.1 Site selection

The location of a seagrass enhancement project is key to ensuring that the supporting habitat and conditions are suitable for supporting seagrass beds. Areas that have previously supported seagrass beds may have changed to an extent that any habitat enhancement work may be too costly or impractical to reverse to support seagrass beds. The best approach is site selection suitability modelling followed by detailed site assessment and pilot studies. Poor site selection could not only mean wasted time and money but may pose a risk to biodiversity and ecosystem functioning.

6.5.2 Evidence base

Projects will need to assess the nuances and site-specific conditions of potential projects to maximise success. Accurate information or data on historical changes are useful to understand the stressors and threats in an area that could affect enhancement. Data detailing persistence, loss, gain, or recovery of seagrass beds, and environmental drivers affecting their past, present, and future potential distribution, such as light, sediment, temperature and nutrients, will allow an understanding of the suitability of conditions to support seagrass enhancement (van Katwijk et al., 2016). In practice this level of data is rarely available and often projects will need to be developed to fill local data gaps.

One issue presented by seagrass enhancement is the complete loss of habitat in the past due to a change in environmental dynamics or anthropogenic activities, thereby losing the conditions necessary for their growth, even where there were extensive beds in the past. Also burrowing of infauna such as lugworms (Arenicola marina) may reduce seagrass density and biomass, by disrupting the root system, i.e. bioturbation, as recorded for Z. noltii in the Wadden Sea (Philippart, 1994).

A key barrier restricting the success of seagrass conservation and restoration is the lack of understanding of ecological feedback mechanisms (Maxwell et al., 2017). Feedbacks between seagrass, other organisms and abiotic conditions can be important for the stability and resilience of seagrass ecosystems. Additionally, the loss of seagrass can impact all trophic levels, due to feedbacks and interactions between seagrass and local environmental conditions (Gutíerrez et al., 2011). The interactions between seagrass and local environmental conditions can result in non-linear relationships between increasing pressure and ecosystem responses (Maxwell et al., 2017). Seagrass meadows may be able to buffer environmental stress to a certain level, but that the capacity of feedbacks to stabilise the ecosystem may be lost beyond this threshold, resulting in ecosystem degradation (Carr et al., 2010).

6.5.3 Methodology

There is no one way to restore seagrass meadows, just an emerging set of ‘good practices’. Broadly seagrass restoration falls into two techniques, restoration via the use of seeds, or via transplantation. However, the methods deployed will depend on a variety of factors, from seed availability, to available labour. In Sweden, local ‘Regime Shifts’ have prevented natural recovery and restoration of lost eelgrass beds along the Swedish west coast (Moksnes et al, 2018) and the short growth season in high latitude environments pose challenges for eelgrass restoration, particularly in areas that receive little light due to e.g. depth or reduced water quality conditions. (Eriander, 2017).

If following the ‘seed method’, results suggest that flowering shoots should be harvested when >50% of the spathes have developing seeds, and that shoots should not be stored longer than 40 days in tanks to obtain an optimal release of viable seeds (Infantes and Moksnes, 2018). In North Wales, Project Seagrass time their seed collection in Porthdinllaen for the first two weeks of August to coincide with this harvest window. However, anecdotal evidence from current Project Seagrass projects in the Solent and Loch Craignish suggest there is variation across sites with southern beds maturing earlier than northern beds.

Critically for large-scale restoration, the collection of seeds for manual planting at regular spaced intervals away from existing beds ensures reduced competition with existing vegetation. Such competition can be a factor compromising seedling survival (Johnson et al, 2020).

If adopting a transplanting method, then modelling (e.g. Adams et al, 2018) suggests that mimicking key emergent traits successfully simulates this positive density-dependent facilitation, thereby increasing growth and survival of isolated transplants and enhancing restoration yields (Temminck et al, 2020). However, yet again this will be site specific, with the success of Zostera marina transplant correlating with sediment type (success was positively related to the air-filled porosity of the substrate media and were negatively related to the organic matter content (Xu et al., 2018)).

Due to the number of projects focusing on seagrass restoration and habitat enhancement, a range of novel technologies have developed to help reduce cost and time resource requirements, and to facilitate the scaling up of small-scale projects (Zan et al., 2020). These include buoy deploying seedlings where reproductive shoots are suspended above meadows to increase seeding( REF); dispenser injection seeding whereby sediment and seeds are mixed and dispensed into sediments using sealant guns (REF); anchored shoots using iron nails, artificial in-water structures to anchor and protect shoots; and use of aquaculture systems as seagrass nurseries. In the latter case, Swansea University and Project Seagrass have carried out trials in collaboration with WWF for mechanised collections and a seagrass nursery, with funding to trial seed injection in 2022. However, NatureScot currently advises against the use of mechanised approaches due to the lack of robust data on the impact of such techniques on the donor beds and existing natural habitats.

Due to the wider understanding of seagrass ecology and biological and physical environmental parameters in some areas, there are also opportunities for developing environmental engineering projects. These may be used to enhance local conditions and habitats to increase restoration success, albeit not in Scotland where information is lacking. However, the application of ecological engineering principles can in theory assist with integrating enhancement projects into coastal development or remediation work. This would be relevant where the conditions to encourage settlement and establishment are included in development design or can be developed as a standalone enhancement project in its own right.

Whilst there is a wealth of experience to draw on when developing an enhancement strategy in relation to seagrass beds, many of the approaches deployed globally may not necessarily apply in Scottish coastal waters and to date there are no seagrass restoration monitoring programmes in Scotland. Care will need to be taken to ensure that the final measures will be appropriate for the specific site and project objectives as there is no ‘one size fits all’ solution. Whilst data from other parts of the UK may be useful, caution should be applied when developing site-specific enhancement projects to maximise efficacy. For example, if seeding, then dispersal mechanisms may have to be considered regarding specific tidal and metocean conditions, particularly in shallow areas (Eriander, 2016; Moknes et al., 2021; Tan et al., 2020).

6.5.5 Management

Suitable planning from the outset is noted to be of significant benefit to seagrass enhancement projects, taking into account what the follow on considerations should be in terms of techniques or practices to be implemented. Strategic prioritisation of efforts has been developed which recommends the initial focus to be on the original stressors, whether to mediate or remove the stressor, whether the environment is altered too much, as well as historic changes to habitat area and environmental drivers (Tan et al., 2020). An understanding of the environmental pressures that resulted in the loss of seagrass extent will be required where possible  to correctly plan a habitat enhancement project, though this will be a challenge in many cases when the cause and effect relationship cannot be determined. Good planning and baseline measurements supported by habitat suitability monitoring is key to this process. Confirmation that the pressure has been removed or adequately managed and reduced will be required to confirm the area is suitable to enhance the habitat and promote recoverability. Direct impacts from human activity include, but are not limited to fishing, aquaculture, boating and associated anchoring, and habitat alteration (dredging, reclamation and coastal construction).

Campbell (2002) also set out a framework for developing a successful habitat restoration framework that can assist with addressing these aspects through the application of a series of decision-making flow charts.

There have been many small-scale restoration trials showing success around the globe. However, the challenge remains to translate small-scale success into large-scale restoration programs. Larger projects require long term commitment and collaboration from a number of stakeholders including local communities, NGOs, government and project partners. Along with the often high labour costs associated with implementation, financial challenges exist from the need to ensure propagation and long-term establishment, repeated planting efforts due to losses and a long term monitoring strategy to inform adaptive management measures. As such long-term planning at the start should take into account what is realistic and feasible in terms of scale and longevity.

6.5.5 Monitoring

Long term monitoring data prior to enhancement and following restoration or enhancement work is often lacking. Data that addresses and reports on the rates and patterns of seagrass loss, likely drivers of these losses, identification of potential restoration sites, and monitoring the success of the intervention is not routinely available. Long term monitoring programmes can often cost more than the enhancement or restoration work itself meaning there is often a lack of data. However, this information is required to confirm the efficacy of restoration methods and can also be used to make adaptive management decisions. (The fundamental role of ecological feedback mechanisms for the adaptive management of seagrass ecosystems is provided by Maxwell et al. 2017.)

Unfavourable conditions include continuous sediment resuspension and high turbidity, lack of stable sediments for seedling growth, and strong wave action that damages or uproots plants (Maxwell et al., 2017). Most seagrass monitoring programmes already include biotic as well as abiotic components but with the abiotic variables representing the conditions of the coastal area in general, and not measured at the scale of the seagrass meadow, which should be included (Maxwell et al., 2017).

6.5.6 Engagement

Stakeholder engagement is noted to be critical and stakeholders should be engaged wherever possible, regularly from the start and throughout project development, with stakeholders ranging from local communities, local and national NGOs, and government bodies. Where stakeholders’ buy-in determines the success of a habitat enhancement project (most if not all cases), early engagement should aim to ensure that they are willing to engage, assist and contribute. In this way, local stakeholders can develop a sense of ownership with projects that can add to the long-term sustainability of a project through community involvement. This has been enhanced through community funds in some cases, e.g. an award provided by Project Seagrass to fishermen to help engage, one form of community engagement to involve ‘citizen scientists’.

Early engagement with communities and stakeholders is key and could assist with reducing monitoring costs through the use of appropriately trained volunteers to assist with monitoring. In the UK SeaSearch is a good example of long-term data collected by ‘citizen scientists’ that could be used as a model to assist in the development of monitoring programmes.

6.5.7 Benefits

The key benefit noted in the literature includes the promotion of positive biological interactions with other species (Tan et al., 2020).

6.5.8 Risks

Seagrass restoration projects can be costly and time-consuming particularly where they are developed on a large scale. Transplantation of shoots can require a lot of time resource and careful handling, meaning that a large coastal enhancement or restoration project could require significant funding. Whilst seeding can reduce costs of collection and deployment, the establishment success of such an approach will be lower (Eriander, 2016; Moksnes et al., 2021). In Scotland, there is currently no facility with the appropriate facilities aligned to enable seagrass restoration at scale. This is a need that requires investment in facilities aligned to oysters and other marine habitat restoration. Any removal of seeds or shoots from existing seagrass meadows must also be carefully managed to ensure there is not an impact on the sustainability of the existing meadow. Impacts on established and healthy meadows may undermine the aims of any new project.

7. SALTMARSH

7.1 Overview

Restoration of saltmarsh, to mitigate historical and ongoing losses of habitat, has been progressing since 1991 in the UK, with most efforts focused on managed realignment, i.e. the landward realignment of coastal defences and subsequent tidal flooding of reclaimed land (Burden et al., 2020) and conservation grazing management to improve the condition of existing saltmarsh through agri-environment schemes to potentially counteract biodiversity loss as a result of grazing livestock (Mason et al., 2019). Saltmarsh enhancement and restoration to date have typically depended on coastal engineering and construction works to create the right conditions for saltmarsh habitat. They are also being increasingly considered as an alternative and NbS to significant coastal engineering schemes due to the escalating building and maintenance costs. However, these may still require small engineering works.

For saltmarsh, ‘stacking’ of key benefits and ecosystem services e.g. flood protection, habitat creation, carbon storage and sequestration and recreation, make them potentially attractive projects as NbSs. Saltmarsh projects are often driven by land management as well as adaptation and resilience to climate change. Most saltmarsh enhancement is managed realignment which generally involves inundation of seawater to form or re-establish the habitat and does not generally require seeding as propagules are generally available from adjacent and existing habitat (though a few experimental projects have, see below) and rely more on engineering interventions or long-term natural change/regeneration.

7.2 Projects

NatureScot has been involved in one of three Scotland saltmarsh schemes, as detailed below.

7.2.1 Scotland

The Green Shores Project is a long-standing partnership originating from the University of St Andrews to restore saltmarsh in the Firth of Tay and Eden Estuary and in the Dornoch Firth on the east coast of Scotland. It is a long-term project that began in 1999 with the Eden Estuary project which focused on translocation and restoration of saltmarsh, with success to date. The estuary had extensive saltmarsh habitat, however, the development of an air base and golf links led to the loss of the upper marsh zone due to subsequent ad hoc coastal defences that were constructed, including soil and turf embankments, low cliffs of rubble and inorganic waste, and gabion walls (Maynard et al., 2011). The Eden Estuary project component was considered more of a trial with a very gradual application, with the planting of saltmarsh as the sediment could not maintain seedlings naturally. Restoration efforts within the Firth of Tay and Eden Estuary have been implemented to mitigate degradation and since 2000, Maynard (2014) has been utilizing a direct transplantation approach. Sea clubrush (Bolboschoenus. maritimus) plants were harvested from donor marshes within the estuary and transplanted onto selected bare upper mudflat sites to encourage the spread of existing marsh as well as produce new areas (Maynard, 2014). The Green Shores Project is the only project NatureScot have been directly involved with, providing key funding (Saltmarsh in the Fringe 2014-2016) and advice.

Other projects in Scotland include the Nigg Bay Coastal Realignment Project (Meddat Marsh), within the Cromarty Firth, which was breached in 2003, removing the engineered flood protection in place since the 1950s. RSPB purchased 25 ha of land behind the 1950s seawall that was unable to prevent the tidal flooding of the reclaimed land. The scheme was led by RSPB (who have a Nature Reserve on-site) and focused on restoration. It provides some useful lessons learned to inform this project (Chisholm et al., 2004), as the Nigg Bay project was the first of its kind in Scotland and therefore there was no experience of the consents or the processes required for securing those consents. The following regulations were required for this project: SSSI consent (Wildlife and Countryside Act 1981); Appropriate Assessment (Habitats Regulations); Consent for coastal protections works (Coastal Protection Act (1949) part I (coastal protection)); and a FEPA licence (Food and Environment Protection Act 1985). An Environmental Impact Assessment (EIA) was not required for this project; however, the RSPB commissioned a Design and Impacts study, which included modelling and various realignment design scenarios (Elliot, 2015).

There are three projects on the Firth of Forth, including Skinflats (RSPB), Kennet Pans (both managed realignment) and Black Devon Wetland regulated tidal exchange, as identified on the Online Marine Registry (OMReg) Habitat Creation Scheme Database, as well as Montrose Basin, a very small 0.3 ha managed realignment project.

7.2.2 UK

There are more than 70 coastal habitat creation case studies in England with a few in Wales which vary from managed realignment to beneficial use of dredged sediment or unmanaged realignment, as logged in the OMReg Habitat Creation Scheme Database^{Error! Bookmark not defined.}. Managed realignment projects include Paull Holme Strays, Medmerry, Steart Coastal Management and Northey Island. The Paull Holme Strays Managed Realignment project has created 80 ha of intertidal habitat including 30 ha of saltmarsh. The project is part of the Humber Flood Risk Management Scheme and was designated a SAC following completion of the successful project. The Medmerry Managed Realignment project is the only open-coast managed realignment in the UK, the project aimed to provide coastal flood protection and to create a large expanse of coastal habitat. The Steart Coastal Management project is one of the largest coastal wetland creation projects in the UK, creating 262 ha of intertidal habitat. The largest saltmarsh restoration project in the UK is the RSPB Wallasea Island Wild Coast project on the Essex coast, which aimed to transform nearly 800 ha of farmland back to wetland habitat by the end of 2018, approximately 400 years after reclamation (Burden et al., 2020). Of the land reclaimed 321 ha will be saltmarsh habitat. Restoration of fringe saltmarsh is also starting to be considered as a natural solution to flood protection and wave attenuation along estuarine foreshores. In Wales, Cwm Ivy marsh was flooded in 2014 when a sluice gate gave way under pressure from floodwaters causing the sea wall to fail. As part landowners, the National Trust’s ‘Shifting Shores’ report coastal realignment was allowed to happen as naturally as possible changing habitats from freshwater to saltmarsh. Three years after the breach the marsh was fully exposed to regular tidal inundation with recognisable saltmarsh plant and animal communities.

7.2.3 International

Many of the USA’s tidal wetlands have been restored for the benefit of waterfowl, shorebirds and other wetland-dependent plants and animals since 1997, through the efforts of the Department of Energy and Environmental Protection’s Land & Water Resources and Wildlife divisions. The Department of Energy and Environmental Protection, in conjunction with many project partners, has completed more than 70 tidal flow restoration projects (over 1700 acres) including for example the Tidal Wetlands Restoration Project, Long Island Sound, Connecticut. Key to the success of this project was the identification of key ecosystem targets and indicators used for projects across individual schemes throughout the project ensuring lessons learned were transferable. These indicators were based on ecological and social metrics underpinned by sound science rather than policies, therefore giving resilience to changing priorities and ensuring consistent and long-term monitoring. The introduction of key legislation for the rehabilitation and restoration of degraded tidal wetlands, and established requirements for organisations to minimise adverse impacts to coastal resources, including tidal wetlands, in their decision making.

The Cheverie Creek Salt Marsh Restoration Project was the first restoration undertaken in Nova Scotia Canada, undertaken between 1999 and 2005. Originally a pilot project, it aimed to restore tidal flow to Cheverie Creek, improving the hydrologic integrity of the site, increase bird and fish populations and enhancing the saltmarsh habitat existing at the site and increasing the extent of saltmarsh habitat (30ha) (see project factsheet). As this project was the first in Nova Scotia, it required actively networking with government agencies and other restoration practitioners in order to develop a protocol, build relationships and earn support for future projects. Moreover, the project team worked closely with the local community and implemented a number of educational programs in order to inform the public about the importance of saltmarsh ecosystems and directly involve the community in the restoration process. Post restoration long-term monitoring has taken place for seven years (2005-2011) after the completion of the restoration project. Monitoring has focused on the physical and biological components of the Cheverie Creek system (both before and after restoration), as well as those of the Bass Creek reference site, in order to record ecological changes and habitat / species responses to restoration.

This project set out the groundwork for future restoration efforts by filling in some of the gaps in knowledge and skills that were existent in this field. There was a lack of data on the extent and condition of saltmarshes and their potential for restoration; there was little information and technical expertise for saltmarsh restoration in Canada, and there was a lack of clarity about the roles and responsibilities of practitioners and the regulations and permits pertaining to saltmarsh restoration. This project also helped draw attention to the imperative for saltmarsh restoration in the Bay of Fundy.

7.2.4 Relevant Projects Focused on Other Features

Experience with other similar habitats / species was not considered for saltmarsh since sufficient information was available that related specifically to this feature.

7.3 Management

7.3.1 Consenting and Policy

Saltmarsh realignment / restoration has been ongoing in Scotland for a few decades. However, as stated above, several of the projects were the first of their kind, and therefore result in a lack of appropriate policy guidance. In Scotland, SEPA issues licences on activities that may cause an impact on wetlands including saltmarsh and an assessment of the impact is made as part of the licensing or planning application. Saltmarsh is protected through legislation and regulatory mechanisms established under the Water Framework Directive, Nature Conservation (Scotland) Act 2004 and the Habitats Directive, as well as the Flood Risk Management (Scotland) Act 2009 and the Coast Protection Act 1949 regarding coastal management and flood risk management. Saltmarshes are also identified as a priority habitat under the UK BAP, with five Local Authorities in Scotland having completed Shoreline Management Plans, as for Angus, Ayrshire, Dumfries and Galloway, East Lothian, and Fife. Any works taking place below MHWS may require a marine licence. Should a marine licence be required, Marine Scotland highlight that applicants must provide an assessment of the effects of their proposed activity in support of their application. This may involve the collection of baseline data and studies to assess the effects. As noted previously in a lease may be required from CES.

7.3.2 Biosecurity

Saltmarshes may be vulnerable to the introduction of INNS which threaten native species; however there have only been a few cases to date in the UK concerning mitten crab (Eriocheir sinensis) burrowing into creek banks and causing erosion; and possibly also Spartina anglica, though this is generally accepted as part of the native flora now. Therefore, a biosecurity plan is needed to mitigate risk, as supported by the Scottish Invasive Species Initiative. Protocols may include a requirement to e.g. check, clean and dry all equipment entering or leaving the area to prevent eggs, spores and sediment from being transferred between sites during translocation. Also recommended is natural colonisation prior to planting and transplantation between sites close together to prevent genetic differences (Defra and Environment Agency, 2007a). Consent is also required from NatureScot for the introduction of a new species. Relating to such risks, the need for appropriate species selection has been identified for the Eden Estuary scheme (Maynard, 2014). In the rest of the UK, full biosecurity plans are in place for protected areas such as the Solway Firth, Cumbria (Solway Firth Partnership, 2015) and Erme Estuary, South Devon (South Devon Area of Outstanding Natural Beauty Estuaries Partnership, 2017).

7.3.3 Genetics

Although genetic diversity is considered an important aspect to consider in restoration ecology, it has gained little attention within the scope of saltmarsh restoration schemes across North-West Europe (Rouger, 2014). Genetic diversity in foundational plant species is critical for species resiliency and ecosystem processes, both of which contribute to restoration success (Tumas et al., 2019). Whilst restoration schemes that allow seawater to inundate a previously embanked area may result in natural saltmarsh colonisation, ongoing monitoring of plant species diversity or functional characteristics has shown that saltmarshes rarely reach the state of a natural saltmarsh ecosystem (Rouger, 2014). This may be because native plant restoration success is dependent on the genetic composition of the source material, specifically the amount of genetic diversity and genetic similarity to the restored area (Tumas et al., 2019). The Saltmarsh Management Manual (Defra and Environment Agency, 2007a) states that as far as possible, plant species selected should represent the natural species assemblage for the area, in order to avoid the introduction of non-native species and problems with species competition; thereby maintaining the biodiversity of the site. Ideally, transplants should be taken from donor sources as close as possible to the intended receiving area, since minor genetic differences may alter a plants ability to withstand particular environmental conditions.

7.4 Guidance

A review of the primary guidance to inform the enhancement of saltmarsh habitats is provided below.

7.4.1 Scotland

There is no comprehensive guidance available for the restoration or habitat enhancement of saltmarsh habitats that is specific to Scotland. However, the two key projects in Scotland that NatureScot have been involved in (Eden Estuary / Dornoch Firth) provide a basis to guide future work. NatureScot is also one of a suite of partners involved in Dynamic Coasts which is based on research to transform understanding of climate change (both a backwards and forwards look). Outputs include guidance, detailed resilience plans for key sites, as well as a map and spatial database of natural coastal defence features. One particular output of note includes coastal change information to plan for development and infrastructure around the coast (NatureScot, 2017). This provides guidance on how to include coastal change in projects; and reference to Local Development Plan policies and National / Regional Marine Plans. Case study applications provide useful insights on information and decisions to consider, barriers and solutions, the most beneficial design and adaptive measures to consider in planning conditions.

The current Coastal Demonstrator project, 2021-2023, is aimed at optimising NbS with investigation and demonstration of the optimised techniques in the field, carried out by the West Sands Partnership. This project will produce an optimised plan, supplementing localised actions through recommendations of Dynamic Coast. This will cover sand dune, saltmarsh and intertidal habitats within the Eden Estuary and West Sands at St Andrews, aiming to maximise benefits for biodiversity, management of flooding and coastal erosion risk, and carbon sequestration.

7.4.2 UK

The UK is now in its 30^th year of saltmarsh enhancement projects and has a wealth of experience to draw on. The Saltmarsh Management Manual published by Defra and Environment Agency (2007a) provides detailed guidance on how saltmarsh conditions should be established and the process for developing the most appropriate programmes for management based on site-specific factors. The UK & Ireland Saltmarsh Restoration Handbook is currently in preparation and will be published in 2021. There has been input from all four devolved nations and Ireland. The Handbook will describe all types of saltmarsh restoration techniques, provide guidance on target setting, success criteria, project timelines, licencing and policy considerations and post-development monitoring.

This new UK handbook will supersede the earlier Saltmarsh Creation Handbook: A Project Manager’s Guide to the Creation of Saltmarsh and Intertidal Mudflat (Nottage & Robertson, 2005). This has to date provided guidance on coastal saltmarsh and intertidal mudflat restoration and creation to support the planning and delivery of such schemes. The handbook covers practical issues arising in the project planning phase. The handbook also addresses site selection, project and management plan design, funding considerations, the regulatory framework and the process of EIA, as well as the practical techniques available to restore and create saltmarsh.

7.4.3 International

In the 1990s, saltmarsh enhancement and restoration in the UK were first guided by work in the USA which had a more established practice at the time. However, this did pose issues given the very different substrate in the UK which is mineral-based (compared to high organic-based content in the USA). Nevertheless, there are a number of publications that detail saltmarsh management measures in the USA. These have a greater focus on reviewing existing management practises over the development of effective future management practices (Borde et al., 2004; Niedowski, 2000).

7.5 Appraisal of Lessons Learned to Inform Framework

Whilst a detailed review of lessons learned from case studies is provided in ANNEX 4: Detailed Case Study Review, highlights raised in guidance material and strategic reviews specific to saltmarsh are listed below.

7.5.1 Site selection

Globally, saltmarshes are well studied with evidence available to identify appropriate physical, biological and chemical characteristics required to promote natural functioning of saltmarsh habitats for long-term functioning and self-restoration. Saltmarsh does not conform to typical patterns of succession with the upper marsh often continuously being eroded and then accreted over time. Whilst there are often complex relationships and processes that must be analysed and understood there is a solid base of evidence to inform future enhancement projects (Borde et al., 2004; Defra and Environment Agency, 2007a).

A key consideration at the conception stage of a project is to identify the most appropriate sites for restoration or enhancement. The key steps of site selection identified in Borde et al. (2004) are as follows:

• Site assessment involving the collection of information (including desk-based or data collection) to adequately characterise or describe the past, present, and future conditions.
• Development of specific criteria for restoration sites, such as level of site alteration, proximity to healthy wetlands, and target functions. The criteria will vary depending on the goals for restoration.
• Prioritisation of approaches which could include a quantitative or semi-quantitative ranking protocol based on site-selection criteria.

The Defra and Environment Agency (2007a) saltmarsh management manual goes further than Borde et al. (2004) with a detailed description of site appraisal in order to develop a robust enhancement strategy. The Saltmarsh Management Manual has a full appendix with a site appraisal tool that effectively applies the steps above. These are outlined below:

1. Define clear management objectives.
2. Describe the baseline environment (including the pressures / issues impacting saltmarsh habitats).
3. Assess the implications of the alternative management options for the baseline environment.
4. Define the extent of any predicted impacts and actions (in environmental, social and financial terms).
5. Select the option that will best achieve the management objectives (including do-nothing), provide the greatest benefit and the best value for money.
6. Design and implement a monitoring programme.

Identifying the function of a particular saltmarsh and how different abiotic and biotic factors interact can be challenging. The function is often determined by the shelter afforded by large scale coastal morphology and so site selection is often dependent on consideration of conditions across a much larger scale than just the saltmarsh itself.

More local factors which also have to be taken into account include local tidal dynamics, sediment transport pathways, locally generated waves and the presence or absence of vegetation and vegetation type (Defra and Environment Agency, 2007a). Natural hydrology is necessary for restoring functional coastal marshes, and this is often accomplished by returning tidal inundation via a breach or removal of barriers such as dykes and levees, or excavation of fill. However, this is challenging to predict, and adequate baseline data is required (Borde et al., 2004).

Defra and Environment Agency (2007a) note that in several estuaries, particularly on more sandy substrates, there appear to be no absolute preconditions for the growth of colonising vascular plants and the subsequent development of saltmarsh. At the lower limits, saltmarsh growth is controlled by the physical conditions, and by interspecific plant competition at the upper limits. Both are subject to small scale and local variations which impact plant and animal community reassembly. The Saltmarsh Management Manual identifies a number of questions that should be answered in seeking to identify the most appropriate location and measures for habitat restoration.

Around the UK, coastal development has resulted in pressures along the landward edge of coastal habitats where there is often insufficient space to allow natural processes of accretion and erosion to take place. This ‘coastal squeeze’ will often mean that managed realignment is prohibited. Similarly, sea walls or breakwaters that can affect natural tidal processes may mean saltmarsh habitats that are more remote from coastal development can still be affected through related tidal processes. This may result in these areas being rejected for enhancement or restoration projects (Defra and Environment Agency, 2007a). It is important to identify such areas to ensure resources are not wasted where there is little prospect of effective restoration being achieved.

7.5.2 Management

When sustainably managed, saltmarshes will lead to the establishment of natural physical processes that self-manage / self-restore (Defra and Environment Agency, 2007a; Borde et al., 2004). Thus enhancement or restoration projects should aim to support and promote natural ecosystem functioning through the application of management measures aligned with natural physical processes. Defra and the Environment Agency (2007a) have carried out a detailed appraisal of management options: including managing grazing pressure, planting sedimentation fences, intertidal recharges and breakwaters, as well as hard engineering constraints, benefits, monitoring considerations and site suitability. Other key publications consider a similar range of management options (Niedowski, 2000; Bordet et al., 2004). The UK manual advises on constraints in terms of where conditions would be appropriate for each measure and monitoring considerations that should be taken into account. However, all guidance stresses the importance of ensuring that projects are appropriately planned with the most effective measure developed on a site-specific basis.

Difficulties arise in the development of effective restoration or enhancement of saltmarsh habitats due to the difficulties in understanding the complex interactions of the biotic and abiotic factors that support healthy saltmarshes. Borde et al. (2004) provide examples of management measures that appear to work in the short-term but have proven ineffective in the long term. As mentioned above, a key element in mitigating the risk of applying ineffective measures is to ensure projects incorporate adaptive management measures informed by robust monitoring and data collection.

Adequate assessment of coastal restoration requires not only a long-term, systematic approach to monitoring but also a coordinated experimental research program to explain patterns that emerge from the data (Zedler, 2001). This can often be prohibitively expensive, particularly for smaller community-based programmes. Any projects should therefore aim to be realistic about what can be achieved with the resources available.

There may be some specific difficulties associated with management measures which may add further costs, logistical challenges or feasibility issues and should aim to be identified early in project development. For example, if using dredge spoil, the spoil will need to be clean and free of chemical contaminants, procurement of vegetation may have long lead-in times, and some measures may require regular and ongoing maintenance over a significant period of time. In some circumstances costs may favour a process of managed realignment; however, as noted above, issues with coastal squeeze may render this option unfeasible. Remedial techniques (i.e. silt recharge, planting) may be cheaper initially than implementing sound coastal engineering works. However, if there is a requirement for long-term and sustained management and mitigation, this may offset the initial cost of hard engineering works. Therefore, the cost of the total project / scheme should be taken into account when developing the most appropriate strategy. Costs should also take into account ongoing monitoring which will be key to the implementation of an adaptive management strategy. This should consider the costs of initial baseline studies and ongoing monitoring and should aim to feedback into future projects by informing lessons learned.

It is useful to understand how current saltmarsh condition compares with a ‘natural’ saltmarsh in any given site. Often anthropogenic pressures have changed saltmarsh over a period of time such that identification of the original condition is not feasible. Under these circumstances, modelling can be used to understand what the original extent may have looked like. The project should aim to be realistic about what can be achieved and projects should be aiming to re-establish and support natural ecosystem functions and pathways rather than trying to achieve set metrics in the form of extent of vegetation coverage.

7.5.3 Monitoring

All guidance promotes the importance of underpinning development with robust site-specific data and monitoring efficacy through long term ongoing monitoring that incorporates adaptive management. Robust monitoring and adaptive management aim to mitigate the risks associated with the uncertainty in the implementation of management measures.

Most of the practical measures for the management and mitigation of saltmarsh habitats have been implemented and monitored in some form. Whilst there may be additional technologies that increase the speed of application of some measures, the main recent developments are applicable to the project planning stages. For example, satellite remote sensing technology can be utilised for monitoring across large spatial extents and can expand analysis beyond a single location to determine change and/or loss of saltmarsh habitat as a result of stressors, both natural and anthropogenic (Campbell, 2018). The use of satellite imagery has also been used with Google Earth Engine to develop an unsupervised decision tree classification method that automatically classifies satellite images into saltmarsh vegetation, mudflats, and open water (Laengner and van der Wal, 2020). Remote sensing may be particularly useful for understanding current conditions and historical change and can significantly decrease survey costs, as well as help, maximise the efficiency of monitoring future monitoring programmes.

Detailed numerical modelling is now available to inform physical processes that may affect the efficacy of a monitoring programme. This has never been more important with a requirement to consider climatic and sea-level changes in future projects. Numerical modelling can therefore be used at the local scale to help inform processes that could affect erosion and accretion, but also at a wider scale to determine how sea-level rises or how more extreme weather events could impact project management measures. This is particularly useful for the application of managed realignment where it often involves the landward migration of saltmarsh until it reaches a natural equilibrium.

7.5.4 Benefits

Saltmarsh provides important ecosystem services related to its flood control, coastal defence, pollution control, waste disposal and the maintenance of water quality; it also supports fisheries, agriculture, recreation and tourism. This results in a range of pressures but also provides opportunities to incorporate sustainable development into management practices which can raise awareness and help gain support for restoration or enhancement projects.

The wider ecosystem benefits for saltmarsh extend beyond ecological conditions relating specifically to the marsh itself e.g. providing habitats and roosting areas for birds, notably waders and wildfowl. These benefits can be measured by including regular monitoring of birds, for example, to assess the broader value of the project for biodiversity.

8. COASTAL SAND DUNES

8.1 Overview

As with saltmarsh, sand dune enhancement and restoration is often linked with coastal engineering and construction works. However, there is also considerable focus recently on restoring natural sand movement dynamics in coastal dunes i.e. ‘working with natural processes’ to restore lost biodiversity and enhance the proportion of early successional habitats which support many rare sand dune specialist species. In sand dunes, activity, therefore, focuses around management issues such as forestry, coastal sediment exchanges, as well as reversing the loss of habitat and biodiversity which has occurred through ecological degradation and on- and off-site pressures such as eutrophication. Sand dunes are exposed to several stress factors including loss or decline of traditional grazing practices, climate change (e.g. rising sea-level, changes to storminess, temperature, and precipitation), coastal erosion, atmospheric nitrogen deposition and groundwater contamination, and human-induced habitat disturbance (Burden et al., 2020; Jones et al., 2011).

Projects

NatureScot has been involved in a few Scotland coastal sand dune schemes, as detailed below.

8.2.1 Scotland

The West Sands Dune Restoration Project was initiated by St Andrews University and has been ongoing since 2000, with direct involvement by NatureScot through The West Sands Partnership. It is located within part of the Eden Estuary SSSI, the Firth of Tay and Eden Estuary SAC. The partnership was set up in 2010 after a major storm, causing coastal erosion and flooding (impacting farmland and St Andrews golf course). The dynamic nature of shifting sand dunes is used to provide a natural defence and replenish vulnerable areas of shoreline, partly through the use of fences to help trap blowing sand. The Fife Coast and Countryside Trust secured a licence to remove tens of thousands of tonnes of sand from a ‘donor’ site (where sediment was accreting) to re-profile the dunes. The enhanced habitat has provided better resilience and protection from flooding and erosion, with the current status reported as ‘recovering’ as a result of the restoration efforts. In, 2012 The West Sands Partnership agreed and published the Management Plan for the West Sands, St Andrews, from 2012-2025 (Fife Council, 2012), which includes the objective of restoring the entire dune system.

The Sand Dune Restoration Project is a trial site by the Forestry and Land Scotland (FLS) in Morrich More, Tain. The project aims to remove established trees, which were planted decades before in an attempt to prevent dune erosion. The project aims to create conditions to allow dune vegetation to recolonise the area and support the natural process to conserve the coastline. The project is also located within the Morrich More SSSI, which in turn is part of the Dornoch Firth and Loch Fleet SPA and the Dornoch Firth and Morrich More SAC.

Other sand dune enhancement / restoration projects planned in Scotland include the Uist Resilience Enhancement project located in the Outer Hebrides, currently anticipated by NatureScot. Also, see the Coastal Demonstrator project in Section 7.4.1.

8.2.2 UK

In the UK there have been increasingly large-scale restoration activities, which learn from experience in The Netherlands and build on much smaller-scale restoration activity since the 1980s. Trial remobilisation actions at medium to large scale were conducted at Kenfig dunes in Wales prior to 2010, and more recently at Newborough Warren in Wales from 2013/14 onwards. At present, there are two major multi-million EU LIFE program funded initiatives in England and Wales, with match-funding from Heritage Lottery Fund and other sources. These are the SoLIFE project in Wales and the Dynamic Dunescapes project primarily focusing on sites in England.

8.2.3 International

There is considerable international project work in Europe, primarily in The Netherlands, but also from Belgium, Denmark and France. These have been funded via LIFE projects, but there is also activity within dune systems owned and managed by water companies or consortia (e.g. Amsterdam Water Supply Dunes) and nature conservation organisations in those countries. For the Netherlands and Belgium, there has been substantial dune restoration since the early 2000s, increasing in scale and ambition. This includes extensive management of the invasive tree species Prunus serotina, large scale creation of notches in leading dunes, and extensive habitat modification to create areas of bare sand. Much of this work has been undertaken in the Amsterdam Water Supply Dunes in The Netherlands (e.g. Geelen and Oosterbaan, 2020), but has also been carried out on other sites along the North Sea coast. Work in Belgium has also improved our understanding of restoration techniques in dune heath.

8.2.4 Relevant Projects Focused on Other Features

Experience with other habitats / species was not considered for sand dunes since sufficient experience was available that related specifically to this feature.

Management

8.3.1 Consenting and Policy

Notice of works should be provided to several bodies including SEPA and NatureScot. Water Environment and Water Services (Scotland) Act 2003 and associated Orders and Regulations (the Water Framework Regulations) provides the statutory under-pinning for the protection of the water environment in Scotland through river basin management planning, regulation of controlled activities and implementation of remedial and restoration measures. The Act and its associated Orders and Regulations constitute the Scottish legal interpretation of the European Water Framework Directive. The Water Environment (Controlled Activities) (Scotland) Regulations 2011 (as amended) or more commonly referred to as the Controlled Activities Regulations (CAR) apply regulatory controls over activities that may affect Scotland’s water environment. The regulations cover rivers, lochs, transitional waters (estuaries), coastal waters groundwater, and groundwater dependant wetlands. Applicants are advised to consult with SEPA (the licensing authority) to identify if a CAR licence is necessary and to determine the extent of the information required by SEPA to fully assess any licence application.

Activities involving the construction of materials upon the seabed, with the movement of beach sediment or the installation of structures below MHWS requires a licence from MS-LOT. Depending on the scale of the proposal it may also require planning permission under the Town and Country Planning (Scotland) Act 1997 if it extends above MLWS (NatureScot, 2000).

8.3.2 Biosecurity

Sand dune sites contain extremely sensitive and specialised species which makes the effect of INNS particularly acute. As many of these INNS originate from gardens, NGOs such as Plantlife via the Dynamic Dunescapes project (Dynamic Dunescapes, 2021) are advocating for proper disposal of garden waste to prevent further spread, as well as check, clean and dry practices. A review of actions at Newborough Warren, Anglesey (Natural Resources Wales, 2013) suggests machinery can play an important role in transporting INNS to new sites, however, it does not lay out methods to prevent this. The movement of sand is often an element in sand dune enhancement. There is guidance which informs on how this should be managed from Defra and the Environment Agency (2007b) and NatureScot (2000), albeit with no reference to biosecurity. The movement of sediment for dune enhancement should also rely on locally sourced material; and similarly transplanting of plant material should rely on local dune systems or, for large projects, a commercial supplier or nursery to limit biosecurity risk (NatureScot, 2000). For the reasons outlined above, NatureScot would recommend a biosecurity plan is provided for all proposals.

8.3.3 Genetics

For dune restoration, genetic diversity may not be relevant for some schemes, e.g. reintroducing sand only from the immediate area. However, any introductions of species or genetic material should consider genetic variation. Parallel variation of genetic and species diversities across a region can also be traced back to anthropogenic alteration, e.g. increased disturbance leading to erosion and fragmentation (Frey et al., 2015). This may result in decreased population size, local extinctions, or genetic drift (Banks et al., 2013). Maintenance of genetic diversity of the restored population is equally of importance, with information on intra- and interpopulation variation considered critical (Greipsson et al., 2004). Restoration measures should also consider genetic variation in isolated populations of threatened species and the genetics of re-introduced species. This can consider establishing new populations at other sites where rare species are at high risk of local extinction and should consider the genetics of trans-located species in re-introduction programmes.

8.4 Guidance

A review of the primary guidance to inform the enhancement of coastal sand dune habitats is provided below.

Sand dune habitat provides an important ecosystem service in the form of coastal defence. Coastal erosion poses a threat to coastal developments around the UK and globally. As such coastal engineering has historically aimed to reduce coastal erosion often at the detriment to natural sediment transport pathways and consequently sand dune ecosystems. Guidance on sand dune restoration or preservation is influenced from two different policy directions: by onshore planning policy aimed at managing sand dune habitats and coastal erosion to protect coastal development, particularly taking into account the pressures of climate change, and by loss of biodiversity and ecological condition due to over-stabilisation of dune systems due to multiple causes. Both aspects have been compounded by historical on-site conservation management which has focused on stabilising any moving sand. More recent guidance instead seeks to re-establish natural processes that self-manage dune ecosystems, provide natural coastal defences and enhance biodiversity.

8.4.1 Scotland

NatureScot (2019) guidance highlights the importance of considering coastal development in the context of natural coastal change. The guidance references the Dynamic Coast: Scotland's Coastal Change Assessment project and outlines how this tool can be used to inform coastal management decisions in highly mobile environments such as around sand dune systems. Whilst the tool is predominantly to inform decision-makers in respect of coastal infrastructure development to ensure future developments are resilient to the pressures of climate change and sea-level rises it may also be useful to inform the development of projects with a focus on these highly mobile and adaptable environments.

In addition, NatureScot published guidance in 2000 (under the previous name of Scottish Natural Heritage) outlining procedures to develop dune management measures: Beach Dunes - a guide to managing coastal erosion in beach / dune systems (NatureScot, 2000). This guidance presented a route map for developing effective practices for restoring natural processes that can self-support dune systems. Coupled with the more recent NatureScot (2019) guidance and better access to coastal processes modelling there is now a more informative evidence base on which to develop future enhancement projects.

8.4.2 UK

A revised Sand Dune Managers Handbook is currently being finalised as part of the Dynamic Dunescapes project (UKCEH et al., 2021). Once finalised the main online version will be available here. The Sand Dune Managers Handbook provides guidance on a wide range of management actions on dunes, which are relevant to restoration and all forms of habitat enhancement. This includes new guidelines on planning restoration to achieve particular target communities in dune slacks (see also Jones et al., 2021), which was previously a major knowledge gap. Other studies have assessed the ability of restoration measures to tackle adverse impacts of eutrophication, in multiple habitats including dunes, and provide guidance on how much nitrogen each management technique removes and how it improves habitat suitability (Jones et al., 2017).

8.4.3 International

Various documents provide guidance on undertaking these activities following work undertaken in the Netherlands and Belgium, e.g. Van Til et al. (2019). At European level, there is a ‘roadmap’ for the management and restoration of dunes to guide activities in this habitat (Houston, 2020).

8.5 Appraisal of Lessons Learned to Inform Framework

Whilst a detailed review of lessons learned from case studies is provided in ANNEX 4: Detailed Case Study Review and highlights raised in guidance material and strategic reviews specific to coastal sand dunes are listed below. There are examples of successful dune restoration projects in Scotland, Wales, England, The Netherlands, France, Belgium and further afield in places such as New Zealand. Development of projects to enhance or restore sand dune habitats can therefore draw on lessons learned across the globe. It is worth noting that climate, sand supply, storm intensity, the type and growth form of plant species (particularly sand-binding species), invasive species and visitor pressure are all important factors that may differ around the globe. As a result, not all techniques may be directly transferable to Scotland.

8.5.1 Site selection

Knowledge of the natural processes of accretion and erosion allows sediment schemes to be designed to complement natural sediment pathways and take advantage of sand dunes’ natural capacity to self-restore (Dahm et al., 2005), whilst providing a cheaper more sustainable solution than alternative coastal engineering works (Esteves et al., 2017). The same principles apply to working with natural dune mobility within dune systems, which can become self-managing or self-regulating if implemented over larger areas, at least for a few decades.

Site selection will pose a number of challenges in ensuring that projects can be effective. Where development has resulted in irreversible changes to coastal dynamics or where there is insufficient space to restore active dune systems large-scale restoration may not be appropriate. At some coastal dune sites, the available space may be sufficient for a sustainable dune (at least in the short-medium term) but may not be adequate to provide complete protection from the worst practical erosion, including climate change effects. Ecological interventions should be considered at a landscape scale, i.e. taking into account the ecological and geomorphological status across sites in order to best plan which activity takes place at which site.

In the case of coastal erosion, in many cases, coastal protection in the form of groynes and breakwaters will have interrupted the natural processes of sediment movement that are required to support natural dune evolution. In these circumstances, it may not be possible to restore the sand-supply system to a state that is considered natural (Nordstrom, 1994). Similarly, where coastal development has occurred behind dune systems there may be reduced space in which dunes can be rejuvenated to become fully mobile. However, in larger sites, there is usually ample room to allow natural dune mobility since migration rates of mobile dunes are typically under 2 m per year over the last 150 years (UKCEH et al., 2021).

The selection of locations for interventions that will encourage natural dune mobility needs to consider the ‘downwind’ occurrence of sensitive features and species. For example, creating a notch in the leading dune will lead to sand burial of habitats immediately inland, and could lead to loss of mobile dune habitat for rare species such as sand lizards. Locations should be planned to avoid such conflicts.

Similarly, the inter-relationships between multiple interventions on a site should be planned to enhance each other rather than conflict. For example, since a key reason for the creation of notches is to increase local windspeeds within a site, it makes sense to co-locate notches where enhanced wind speeds will directly benefit restoration interventions within the dune system where greater sand mobility is required.

8.5.2 Evidence base

Significant developments in mathematical modelling can be used to inform the location and approach to dune management (Borde et al., 2004), taking into account long term coastal processes and met ocean datasets, with consideration of climate change scenarios. Modelling of water table dynamics may be necessary to understand the hydrological constraints on the restoration of dune slack communities and to accurately plan for specific target communities as a desired restoration endpoint (UKCEH et al., 2021).

Site-specific data is required to make the most of planning for any dune restoration or enhancement projects. For example, this may require specialist sediment tracing studies to understand the processes of erosion and accretion; similarly, hydrological monitoring is necessary to understand the pattern of within- and between-year variation in hydrological regimes in order to plan dune slack enhancements. The data will assist in developing the most cost-effective and appropriate management measures to maximise efficacy.

8.5.3 Methodology

Addressing critical coastal erosion and flood risk can be achieved through artificial dune construction or maintenance. However, guidance is moving away from this approach in The Netherlands. More natural approaches such as beach renourishment and enhanced supply of sand to key beach areas are better able to mimic natural processes, taking account of the specific coastal processes across the site. For ecological purposes, both small-scale and large-scale interventions on-site often use heavy machinery, so care needs to be taken in planning access and egress from sites, as well as how to dispose of spoil or material (scrub, invasive species, etc.), which is best removed off-site where possible.

There is a good understanding of the fundamental requirements to implement a successful dune restoration project such as ensuring natural processes are maintained and that there is adequate space to allow dunes to naturally evolve across an area of backshore with low relief (NatureScot, 2000). This is further augmented by access to high-level coastal change information where a preliminary assessment can be undertaken to understand coastal mobility and the risk of significant erosion. Recent understanding on how to design restoration of dune slacks for specific outcomes is now available (Jones et al., 2021; Dune Managers Handbook (once available)).

There may be a delicate balance between enhancing natural dune dynamics and preventing erosion of high-priority habitats, and the relative focus on these two components is likely to differ across the UK. Overall, however, there has been a paradigm shift in dune management towards working with natural processes and moving away from automatic attempts to control natural mobility.

Removal of vegetation cover is a key tool to facilitate natural dune dynamics. Examples of this type of management have proven to be effective in the Netherlands (Arens et al., 2005). However, there are complex interactions between vegetation cover, the type of species involved and dune stability which may need to be considered when tackling invasive species. Interactions between vegetation and hydrology also require a good scientific understanding in order to improve the chance of achieving desired outcomes for restoration in dune wetlands.

There can be logistical challenges with some mitigation measures and the programming of projects should take account of longer lead-in times for any equipment or materials (Dahm et al., 2005; NatureScot, 2000). For example, sourcing native dune pioneer grasses and successional grasses can require setting up nurseries with lead-in times in excess of 12 months. Access and egress for heavy machinery should consider sensitive locations within sites. Planning locations for depositing excavated mineral sand should also consider the consequences for downwind locations that will experience deposition of wind-blown sand (to achieve positive outcomes and to avoid damage to sensitive species or features). It should also consider the potential for high nutrient levels in dumped soils to adversely impact other site components.

8.5.4 Management

Removal or effective management of pressures on dune habitats ensures that restoration or enhancement efforts are not undermined. In the case of sand dunes, pressures related to beach access and human behaviour can be addressed through an effective programme of promulgating information to beach users and local communities, as well as restricting access, signage and installation of low impact crossing points. Pressures related to nutrient inputs are harder to manage since sources are usually off-site. Nevertheless, on-site measures can be effective in reducing the impacts of eutrophication, as well as avoiding pitfalls where some management techniques can exacerbate problems (e.g. supplementary feeding of livestock on site, which acts as an additional source of un-wanted nutrients). Off-site measures to reduce nutrient impacts can sometimes be negotiated with nearby landowners. Removing or reducing pressures is usually a better long-term solution than practical technical management measures to mitigate their effects and in many cases, following the removal of human pressures, sand dune systems have a capacity to self-restore (Dahm et al., 2005), although excess nutrient levels have persistent legacy effects (Jones et al., 2013).

Many established management options will also need regular and ongoing maintenance, e.g. wood, geotextile sandbags and other materials can weather quickly in hostile and abrasive coastal habitats. Again, robust planning from the outset should aim to ensure there is sufficient resource to maintain the project long term. Some restoration measures may require chemical or mechanical control of undesirable plant species, particularly those with persistent rhizomes or which rapidly establish from wind-blown seed sources onto bare sand areas.

The development of management measures should also take into account the appropriate scale of any required works. For example, in areas of open coastline coordinated measures may need to span a large area to support the natural sediment dynamics, whereas in small bays measures may be possible at a smaller spatial scale. Early identification of requirements should ensure adequate resources are secured to ensure the future sustainability of a project. Restoration measures aimed at enhancing natural dune dynamics within dune sites generally require larger-scale interventions to be more successful. However, small scale activities focused on the scale of natural blow-outs can also achieve benefits for plants, soil pH and species dependent on bare sand, depending on the context and desired outcome (e.g. Van Til et al., 2019).

8.5.5 Monitoring

As with all restoration projects, efficacy and management decisions need to be addressed through long term monitoring programmes that can inform adaptive management. The costs of monitoring projects can be significant and therefore should be planned from project inception. These should include monitoring of baseline conditions before restoration takes place, and monitoring in control areas with no restoration in order to show that subsequent changes have been due to the restoration itself, and are not due to external influences such as changes in weather patterns, rabbit grazing, human disturbance or numerous other factors.

Understanding a site’s capacity for change is essential to deciding longer-term engineering options and success of dune enhancement schemes, requiring a programme of monitoring to identify site condition (ecological, hydrological and geomorphological) and specific nuances, as well as implementing a programme of adaptive management (NatureScot, 2000).

Earth Observation and remote sensing play a role in understanding and monitoring coastal dynamics. Dynamic Coasts utilised aerial photographs, LiDAR and collaborated with NatureScot to collate Pan-Government remote sensing data to include pan-Scotland surveys as part of their methodology. The remote sensing data allows the reappraisal of large sections of the mainland east coast, including the main firths and more spatially limited areas elsewhere (Fitton et al., 2017). The second phase of research (2018-2020) under Dynamic Coast includes trialling novel Earth Observation technology to improve estimates of coastal change.

8.5.6 Engagement

To promote a change to human behaviour Dahm et al. (2005) advocate for engaging local communities and establishing community-driven enhancement projects. This allows communities to take ownership and develop a vested interest in a project that can encourage long term engagement, and minimise adverse publicity. Community participation in ongoing monitoring and maintenance of works can also assist with tracking the efficacy of a project and informing adaptive management decisions. For example, the sand dune citizen science monitoring app developed in the Dynamic Dunescapes project is designed for exactly this purpose. Dahm et al. (2005) consider community involvement as one of the most important factors in ensuring the long-term sustainability of any enhancement or restoration works and presents a process for establishing community-based projects detailing when and how communities should be asked to participate and at what stage of project development. It is also useful to enhance local understanding of the ecology of dunes and how they function, which can be essential to head off adverse publicity or misunderstanding around techniques used to achieve large-scale restoration.

8.5.7 Climate change

Guidance should aim to help those involved in planning for coastal restoration projects to take account of the increasing effects of climate change and sea-level rise in the same way that onshore planning policy requires similar considerations for coastal development and infrastructure projects (NatureScot, 2019). Projects will need to consider the effects of extreme storms and ensure restoration work takes into account the risk of one-off extreme storm events that can cause a rapid redistribution of sandbanks and sediment dynamics. A programme of monitoring and adaptive management can aim to address these issues, as can the use of robust mathematical modelling work (Dahm et al., 2005). Enhancing natural dune dynamics is one way to achieve future-proofing for changing climate. Many dune features become self-managing in this context, e.g. new dune slacks behind migrating dunes automatically form at the level of the new water table. Hydrological modelling, with reference to eco-hydrological guidelines for different dune wetland communities (UKCEH et al., 2021) may be helpful to understand potential climate impacts on water tables.

9. DEVELOPMENT OF THE FRAMEWORK

9.1 Initial scoping

As an output of the review, a list of all the information and criteria that may be considered for the framework was initially compiled in a spreadsheet. These were given further sub-criteria where necessary, with supporting text on description, examples and relevant supporting guidance, grouping of all by theme. The table was considered a ‘long list’ from which to prioritise and select those that would be used in the assessment proposal form and associated guidance document.

9.3 Consultation

A two-hour workshop was carried out on 1^st April 2021 with the Steering Group and wider colleagues at NatureScot, led by the GoBe team, including Herriot Watt University. This covered a variety of topics that aimed to provide critical feedback on the framework assessment form, guidance document and report recommendations. 

9.2.1 Overview

A lot of the discussion of the framework involved a high-level consideration of how it is framed and presented rather than which individual criteria to include (or not). However, the discussion was guided through consideration of current issues, the proposed criteria and recommendations.

Overall, attendees agreed that the framework requires an open-ended set of questions rather than a set ‘criteria’, with the proposal outline section providing the majority of the assessment template criteria. The remaining criteria / sections were agreed to still be very useful as an internal checklist for NatureScot to guide ongoing discussions with the applicant, though some of these could be brought into the more high-level proposal outline template. Attendees agreed the essential information to ask is the ‘who’, ‘what’ (organisation, project aims and success criteria), ‘how’ (both methods and costs), ‘when’ and ‘can you’ (permissions etc.) with perhaps a three-stage process of 1) initial enquiry with essential limited information by email, 2) main proposal form with selected criteria and 3) ongoing discussion guided by remaining or a full list of criteria.

However, despite this simplified approach, it was also agreed that it is hard to know what barriers a project may meet without requesting detailed information to evaluate the important aspects to a project’s success. It is therefore critical how the questions are framed to encourage an adequate level of detail.

Some of the key points drawn out from the discussions are provided below under the various areas of consideration.

9.2.2 Proposal Outline and Objectives

A consistent concern was evident around objectives, including the lack of clarity and often only driven by single objectives in proposals. Instead, projects should be looked at from a multi-benefit Nature based Solution (NbS) viewpoint.

9.2.3 Scientific Knowledge

Concerns on insufficient scientific knowledge or baseline data were the most common discussion point, particularly around biosecurity, existing environmental pressures and their management, geomorphology, conservation goals and habitat suitability, with this potentially resulting in a lack of detail in project planning and limited consideration of the wider ecosystem. This may be addressed by encouraging a greater level of strategic thinking at an early stage, to ensure a ‘right project in the right place’ approach.

9.2.4 Project Input Required

Comments on logistics echoed earlier conversations that information is often lacking on the overall proposal outline. As part of the proposal, the applicant should also consider the impact of managing conflicting activities on the site to ensure success. Furthermore, concerns were raised around project time scales and strategy being built around funding rather than the needs of the project itself and any issues which might arise.

9.2.5 Legislation, policy, and guidance

These concerns focused on a potential lack of knowledge from the applicant on issues such as designated sites, legislation, and licensing. There was also a request for greater clarity around how or when a site might receive a protective designation/status itself because of a successful restoration or enhancement project. This also prompted questions over the current legislation and consenting process, and potential for change in the forthcoming National Marine Plan revision where strategic policies on enhancement could be introduced; and linking to upcoming Marine Scotland guidance on social and economic impact assessment.

9.2.5 Pressures and Risk

Issues have been found in providing a full assessment of biosecurity risk and impacts from pressures, particularly around how these currently impact, current management and how these will be managed going forward.

9.2.6 Climate change

Projects need to be adaptable and resilient to climate change. To ensure the long-term sustainability of a project an adaptive management approach that can respond to environmental changes should be incorporated into project proposals.

9.2.7 Data and Monitoring

The importance of gathering data on the site during the planning process was noted as good practice. Some projects have lacked clear baseline data or site-specific data collection to underpin project proposals. Site-specific data should be a requirement, as far as practicable, to support proposed future restoration work. Mapping of potential opportunities more broadly (e.g. nationally) would help this but requires further discussion within NatureScot. The NMP and regional marine plans should also help guide aspects and areas for where restoration projects may have potential. A comprehensive long-term monitoring program was also thought to be lacking in some previous project proposals.

9.2.8 Framework and Guidance Structure

Consideration of science, logistics and monitoring amounted to many suggestions and comments around the content, structure, and purpose of the enhancement framework. Multiple comments requested the framework be used to collect information rather than laying out criteria for projects to meet; another comment asked whether the framework should be approached from a risk assessment perspective. This area also broadened the discussion as to whether the framework should be broken down in to a two-stage process and what elements needed to be part of the initial contact. It was also argued that there may be constraints on some of the criteria and locational, ecological, or regulatory specific factors. Furthermore, it was suggested that there should be more focus on the citizen science aspect of projects, including community engagement and involvement strategy.

9.2.9 Communication

The workshop participants also highlighted concerns with communication. The framework needs to not overburden NatureScot staff as they respond to growing demand in applications with the creation of a framework. A clear pathway for contacting applicants concerning enhancement projects is also needed and could take the form of a website. The framework should also enable applicants to contact NatureScot early on in planning to avoid a major problem developing.

9.2.10 Enhancement/Restoration

Finally, the role of enhancement was questioned including whether it is always the best option holistically. Ecologically it was argued that conserving the natural environment we have needed to be a priority over enhancement. Overall NatureScot needs to consider whether the enhancement project proposed is the most powerful tool for meeting the objectives, with elements such as long-term management success being a key factor.

9.2.11 Actions

Whilst some elements of the workshop were already accommodated by the framework their discussion in this workshop highlighted their necessary inclusion, e.g. interaction with ecosystems and geomorphology, objectives, socioeconomics, community engagement, biosecurity, site pressure, site suitability, designations, permissions, duration, long-term monitoring, and site-specific baseline data. Some points recommended and used to improve the framework included:

• Highlight areas where supporting evidence can be uploaded to aid with application e.g. baseline data, ecosystem services, etc.
• Prioritise the essential information.
• Potentially change the phrasing of the form from ‘criteria’ to ‘information’ or similar.
• Evaluate current criteria and establish which areas might be feature or location-specific.
• Compare socioeconomic consideration criteria to the upcoming Marine Scotland guidance on socio and economic impact assessments.

FRAMEWORK OUTPUTS

As an outcome of the review and workshop, a project assessment form was developed. This was designed to be completed by those planning on developing enhancement projects in Scotland, which we envisage will initially be for one or more of the four focus habitats / species in this project but could be used for others. The form is a digestible size, posing questions to explore the most critical components of a project at the early stages. It is a means by which project proposers can engage with NatureScot so they are able to offer the best level of advice.

The form is accompanied by a full guidance document which mirrors the structure of the proposal form, with a set of eight categories as follows:

1.       Project Information (feature, enhancement type, location, off-site and site process, timescales)

2.       Underlying principles (primary objective, driver and funding, success criteria, scheme alternatives)

3.       Site Profile (natural dynamics, activities and pressures, existing data, baseline monitoring key gaps)

4.       Regulation and management (species, protected areas, activities, access)

5.       Risks (biosecurity, translocation, genetics, wider ecosystem, climate change, socioeconomic, funding, mitigation)

6.       Benefits (biology and ecology, socioeconomics)

7.       Engagement (early engagement, stakeholder group, public outreach, communicating success)

8.       Management, monitoring and evaluation (implementation, data collection and monitoring establishing success)

The framework is considered to be best supported by an iterative process of engagement during project development, where there is an initial discussion by email / telephone focusing on project information (1), followed by submission of the full proposal form and then with follow up discussions with NatureScot providing steer and ad-hoc advice.

SUMMARY AND RECOMMENDATIONS

Through a review of the literature, consultation and development of the proposal form and guidance, a number of recommendations have arisen relating to management, linking to certain legislation and policies, as well as gaps in knowledge and guidance, as set out below.

Regulators

As the number of proposals and engagement with NatureScot grows over time, a more objective approach may be required, as carried out in other countries. For example, this may include site suitability modelling and subsequent prioritisation by NatureScot or through the Marine Planning process. Overall, further research on the features’ ecosystem functions and services are required in Scottish waters, particularly where there is an interest in restoring the feature as a Nature based Solution.

It would be beneficial to measure and document the scale of environmental enhancement over time to demonstrate how such projects contribute to meeting various targets, e.g. UN 2030 Decade on Ecosystem Restoration, MPA conservation objectives and blue carbon contributions to mitigate and adapt to climate change.

It is recommended that NatureScot builds on the project outcomes to influence what will be included in the Scottish Biodiversity 2030 Challenge (which will in turn be informed by outcomes of the UN Convention on Biological Diversity (COP15) in 2021).

Engagement

The success of citizen scientist monitoring programmes in the UK has been recognised through various programmes such as UK SeaSearch, the Dynamic Dunescapes Citizen Science App and NatureScot’s Community-led Marine Biodiversity Monitoring Project. Such approaches are being increasingly recognised as one of the key components to success in marine and coastal enhancement projects. Although it is the responsibility of the individual projects to monitor success, projects may benefit from a similar national schemes, should one be set up in Scotland to monitor enhancement project success as the number of projects grows. This in turn could lead to supporting community involvement in such projects and raise awareness.

Ecosystem Services

Restoration and improved management of ecosystems can dramatically enhance the ecosystem services they provide. The main benefits usually come from two areas: i) improvements to regulating services (such as maintenance of carbon stocks, or increased carbon sequestration, lower flood risk, improved water quality), ii) but also improvements to the cultural services and the wellbeing benefit people get from natural ecosystems – greater opportunity to enjoy aesthetic habitats and wildlife. The wider ecosystem service benefits are not always quantified or monitored in enhancement programmes, and more emphasis could be placed on this area. A recently released Handbook for Nature based Solutions (Somarakis et al. 2019) draws on primarily European experience but contains a wealth of indicators and guidance to follow.

Climate Change

Guidance should advise on accounting for the increasing effects of climate change in the same way that onshore planning policy requires similar considerations for coastal development and infrastructure projects. For example, this would account for both one-off events such as extreme storms, e.g. that may cause a rapid redistribution of sandbanks and sediment dynamics, as well as longer-term impacts, e.g. sea-level rise, increased storminess and change in climate envelope for species. Such focus of efforts will help future-proofing for changing climate, with many coastal features becoming self-managing in this context, e.g. new dune slacks behind migrating dunes automatically form at the level of the new water table.

Native oysters

Oyster restoration is still within its infancy in Europe in comparison to the USA. Policy and management measures need to be adapted to develop appropriate best practices relevant to the needs of a project, specifically around knowledge gaps, validation of these, guidance and a methodology for biosecurity in translocation schemes. These actions will require project managers to work with relevant authorities.

Strong biosecurity measures, reinforced by scientific understanding of the vectors of disease and INNS, can be incorporated at both the project planning (specifically site selection) and operation stages; this is key to safeguarding existing disease and INNS-free oyster populations (zu Ermgassen et al., 2020a).

Protection from pressures such as fishing activity impacts on oyster restoration sites will continue to be an important focus area.

Seagrass

Seagrass restoration projects can be costly and time-consuming with the careful handling required for transplantation of shoots (yet transplantation has a much better success rate than seeding). In Scotland, there is currently no facility with the appropriate facilities aligned to enabling seagrass restoration at scale. This is a major need that requires investment in facilities aligned to oysters and other marine habitat restoration.

Seagrass restoration is considered in its infancy in the UK compared with other nations, such as the US and several nations in Europe. As a result, management and policy measures require adaptation to develop appropriate best practice guidelines and a policy framework that reflects the requirements of seagrass restoration / enhancement projects in Scotland.

Saltmarsh

Coastal development, seawalls and breakwaters act as a barrier to the landward progression of coastal habitats, impeding natural processes. Moreover, competing interests at the land-sea interface, land ownership, food security, flood defence issues, insurance, cultural and local perceptions of giving land to the sea and changing land use can make the realignment of flood defences a contentious and costly issue. The practice of saltmarsh creation and restoration is well established in the UK and across Europe with (more or less) predictable outcomes. The key factors for implementation are generally logistical, legal and stakeholder-driven. The UK and Ireland Saltmarsh Restoration Handbook (2021) deals with these issues in detail.

Sand dunes

There is substantial new guidance being developed for sand dune restoration, learning from the large-scale application of new (and established) restoration measures. This includes a UK Sand Dune Managers handbook published by Plantlife, based on UK expertise and examples, supplemented with established restoration experience from The Netherlands. A Citizen Science App for monitoring dune restoration has recently been launched which allows the public to undertake a wide range of monitoring activities in support of restoration on dunes. There may be some gaps in relation to Scottish systems, specifically the management of machair, which is not covered and might require different approaches.