# Restoration of benthic habitats in coastal marine environments

Jonathan Sagan, Alain Pibot, Thibaut de Bettignies, Diane Laforge, Isabelle

Gaillard-Rocher, Hippolyte Gilante, Stéphane Pouvreau, Anne Vivier, Alix

Meslin

► To cite this version:

Jonathan Sagan, Alain Pibot, Thibaut de Bettignies, Diane Laforge, Isabelle Gaillard-Rocher, et al. Restoration of benthic habitats in coastal marine environments. LIFE IP Marha; OFB, Office Français de la Biodiversité. 2024, pp.104. hal-05087830

HAL Id: hal-05087830

https://hal.science/hal-05087830v1

Submitted on 28 May 2025

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# RESTORATION OF BENTHIC HABITATS IN COASTAL MARINE ENVIRONMENTS

<figure><img src="image_1.png" /></figure>

Technical note / November 2024
The present document is set within a challenging context regarding the restoration of natural habitats in the face of a continuing and worrying deterioration in their state of health and the ecosystem services they provide. This context is also politically challenging, coming at a time when a European regulation has set highly ambitious targets after 30 years of insufficient application of the Nature Directives. This context of ecological urgency on the one hand, and political demands on the other, required, and will continue to require, a great deal of work to explain the concepts of ecological restoration and the sharing of experiences, given that these concepts are so open to interpretation and that examples are few and far between, poorly documented and, unfortunately, poorly evaluated.

The first steps were therefore to compile a list of measures aimed at restoring benthic habitats and to share an evaluation method developed with PatriNat to objectify the projects presented as thoroughly as possible.

FORE
WORD

After a brief reminder of the theoretical concepts relating to the theme and the European Nature Restoration Regulation, this document presents examples of feedback from work and projects to which LIFE IP MARHA has had access, as well as work in which the teams of the 14 beneficiaries associated with LIFE IP MARHA have been involved.

This document is part of a triptych of deliverables on ecological restoration from the French Biodiversity Agency (OFB):

* the PatriNat project, which aims to analyse and indicate the definitions adopted for restoration, as well as certain principles that structure the concept of ecosystem restoration within the framework of the European Nature Restoration Regulation,

* this LIFE IP MARHA technical note aims to understand the contexts, methods, techniques, strengths and limitations of marine habitat restoration. Its aim is to inform the work and thinking of managers of marine protected areas (MPAs), including OFB departments, as well as decentralised government departments in the context of the appraisal of works and projects in marine areas and the public maritime domain. It should provide food for thought for the implementation of the European Nature Restoration Regulation

* the work of the OFB's Department of Research and Scientific Support (DRAS), guiding the National Restoration Plan, notably through the LittoREX reference platform (page78), which compiles feedback from collaboration with the French Geological Survey (BRGM).
# Contents

## Introduction 4

Context 4

Definitions 6

Ecological restoration in Europe 9

Legislative and regulatory framework for ecological restoration 10

Key milestones 10

Adoption of a European

Nature Restoration Regulation 11

## Methods 16

Selection of feedback 16

Towards a critical analysis 16

Content of feedback sheets 17

## Feedback from each target GHT 19

Seagrass beds 20

01. Innovative moorings 21

02. Removal of end-of-life vessels 24

03. Removal of artificial reefs 27

04. Eelgrass seedlings 30

05. Posidonia transplantation 33

Macroalgal forests 36

06. Cystoseira transplantation 37

07. Kelp transplantation 41

Shellfish beds 44

08. Reintroduction of the flat oyster 45

Maerl beds 48

09. Macro-waste removal 49

10. Adaptation of a shellfish farming practice 52

Sponge, coral and coralligenous beds 56

11. Fishing closed areas 57

12. Replanting of gorgonians 61

Soft sediments (above 1,000m) 64

13. Control of smooth cordgrass 65

14. Removal of the Pacific oyster 69

15. Artificial reef installation 73

## Analysis of collected projects 76

## Ecological restoration guides and tools 78

LittoREX platform 78

Natura 2000 resource centre 78

Guide to controlling invasive cordgrass sporobulus 78

Guide to setting up a Zone for mooring, light equipment (ZMEL) and ecological mooring 78

International principles and standards to guide ecological restoration practices 79

GeoMCE tool 79

Recovery Wheel 79

Specific tools per habitat type 80

Monitoring methods per habitat type 81

## Lessons learned 82

Costs and benefits of restoration 82

Keys to a successful restoration project 83

Conclusion 85

## Bibliography 87

## Annexes 92
## Context

A habitat is a particular environment that can be distinguished by its abiotic characteristics (biotope) and associated biological assemblages (biocenosis), operating on specific but dynamic spatial and temporal scales, within a recognisable geographical area (ICES, 2006; Maciejewski et al., 2016).

Marine benthic habitats that incorporate a diversity of substrate types (e.g. rock, coarse sediment, sand, mud, etc.), environmental conditions (e.g. hydrodynamics, light, salinity, etc.) or even habitat engineer species (e.g. seagrass beds, Lithophyllum pavements, maerl beds etc.), are extremely varied (Michez et al., 2014; 2019). They fulfil a variety of ecological functions for species: nursery, spawning ground, feeding, breeding, protection or resting area (Féral et al., 2012). As a result, many marine species have life cycles that may require different habitats over the course of their lives (Beck et al., 2001). Benthic habitats therefore provide vital biological functions for marine flora and fauna and are the source of ecosystem services that are essential to our society. When marine ecosystems are healthy, they offer a multitude of essential ecosystem services: carbon sequestration, food and energy resources, environmental attractiveness, recreational uses, etc. (de Falco et al., 2005, Fourqurean et al., 2012). Launched in 2012 by the French Ministry of Ecology, the EFESE programme

(French Evaluation of Ecosystems and Ecosystem Services) has produced a summary of the data available on a national scale to describe the status and trends in the evolution of ecosystems, both metropolitan and overseas, terrestrial and marine, as well as the goods and services that depend on them and that benefit human societies (Mongruel et al., 2018).

Although home to a rich and fragile biodiversity, these environments are subject to significant and growing anthropogenic pressures (Korpinen & Andersen, 2016), particularly in the coastal zone (pollution from watersheds, pressures generated by recreational uses of the environment, coastal artificialisation, pressures associated with unsustainable fishing or marine farming, etc.). Marine ecosystems possess varying degrees of resistance and resilience<fnref n="1" /> in the face of these likely degradations (La Rivière et al., 2015; 2016; La Rivière & Hébert, 2023). It is important to note that a return to a pre-degradation state is not always possible if its natural recovery capacity is no longer achievable following a critical degradation and a transition to another stable alternative state (Hughes et al., 2010; Jones et al., 2018).

<figure><img src="image_2.png" /><figcaption>Ghost fishing net near a Posidonia meadow
© Antonin Guilbert/French Biodiversity Agency</figcaption></figure>

<footnote n="1">¹Resistance is the ability of a habitat to tolerate pressure without the significant modification of its biotic and abiotic characteristics, while resilience is the time required for a habitat to recover once the impacting pressure has ceased.</footnote>
<figure><img src="image_3.png" /></figure>

Innovative mooring in the
Anse de Morgat on the Crozon peninsula
© Greg Lecoeur/French Biodiversity Agency

In its assessment for 2020, the European Environment Agency **estimated the proportion of European habitats in poor condition at 81% (European Environment Agency, 2020)**, despite the policies deployed over the last 30 years (**Habitats Directive, Water Framework Directive, Marine Strategy Framework Directive**). The development of additional measures appears essential to reverse this trend. This has led to growing interest in the development of tools for **the ecological restoration of degraded marine ecosystems** (Edwards et al., 1999). The re-establishment of ecosystem surfaces, structures and functions through ecological restoration strategies has therefore recently been identified as one of the "greatest challenges" in marine ecology (Borja, 2020). This is truly a scientific challenge, and one that is reflected, among other things, in the United Nations Decade on Ecosystem Restoration, adopted by the UN General Assembly in March 2019 and whose first part covers the period 2021-2030. It is a call for the global revival of ecosystems and their services (FAO, 2022). At European level, this was reflected in the adoption of a Nature Restoration Regulation by the Council of the European Union on 17 June 2024. Lastly, at national level, France, through the National Biodiversity Strategy 2030 (SNB), has committed to reducing the pressures on biodiversity, protecting and restoring ecosystems, and making profound changes to reverse the trajectory of biodiversity decline.

Today, in many countries, marine ecosystem restoration is an integral part of conservation strategies (Abelson et al., 2016). The ecological restoration of these ecosystems, made up of a mosaic of habitats with varied functionalities and playing a key role in the carbon cycle, can notably help mitigate the effects of climate change, particularly at local levels (Gattuso et al., 2018).

As we can see, the justification for a major effort is clear, and everything is in place politically and strategically to deploy vast programmes to restore natural habitats. But the scarcity of existing scientific and technical references on marine habitat restoration is currently a real problem. Numerous operations have been carried out over the last few decades with the aim of "restoring" an ecosystem compartment, carrying out a scientific experiment in reproduction, transplantation or cuttings, or even developing a fishery or tourism project. Thousands of hectares of mangroves, seagrass beds and coral reefs have been planted, transplanted and cut, and thousands of tons of more or less suitable concrete have been used to create artificial reefs of all kinds along the world's coasts. What ecosystem assessments of this work have been carried out? Has the restoration of the initial ecosystem in terms of its structure, communities and ecological functions been assessed?

**What technical, scientific and ecological rules must restoration operations follow?** We have tried, as objectively as possible, to analyse some of the projects in which our teams were directly involved to some extent, in order to conduct a real critical analysis of the work and analyse the relevance of the actions with regard to the restoration objective.

We hope that these reflections will help to improve the effectiveness and relevance of restoration actions, whether carried out as part of the management of natural environments or as part of the implementation of authorised measures to compensate for the impacts of plans, programmes and projects unable to avoid or reduce all the risks of their environmental impact.
# Definitions

A scientific scoping report prepared by PatriNat is now available (Laforge et al., 2024). Following the adoption of the European Nature Restoration Law, its aim is to analyse and propose a semantic framework for ecological restoration.

There are currently several definitions of ecological restoration. Generally speaking, restoration is a response to the degradation of an ecosystem. For the remainder of this technical note, we will use the definition adopted by PatriNat (Laforge et al., 2024):

> "Restoration (ecological restoration/ecosystem restoration) is an intentional process aimed at enabling the recovery of an ecosystem that has suffered degradation and targeting a reference state. This reference, to be restored or reached, is defined by an appropriate state of all ecosystem components (biotic, abiotic and functional), guaranteeing its long-term integrity. A continuum of interventions can be carried out depending on the level of degradation and its causes: (i) the pressures that led to the degradation are removed or mitigated to a level that allows the natural recovery of the ecosystem, and (ii) if intervention on the relevant pressures is not sufficient to achieve the restoration objective, interventions on the components of the degraded ecosystem may be planned to assist or even accelerate its recovery".

It is important to note that the definition mentions a number of **prerequisite and indispensable considerations** for qualifying an action as "ecological restoration"; namely, an intentional process is implemented, the recovery of an ecosystem is staked out according to a reference state that must also guarantee its long-term integrity, and targeting all ecosystem components.

**A historical dichotomy exists between the so-called active and passive restoration actions.** As this is increasingly subject to criticism, PatriNat recommends that the following terms be adopted as a minimum (adapted from Gann et al., 2019 and Atkinson & Bonser 2020):

* **Natural restoration** (or natural regeneration) is an intervention strategy that involves reducing or eliminating the sources of degradation by acting on the activities generating the pressures, and then allowing the ecosystem to recover spontaneously.

* **Assisted restoration** (or assisted regeneration) is an intervention strategy that involves reducing or eliminating the sources of degradation by acting on the activities generating the pressures, and taking action on the abiotic and biotic components of the ecosystem.

* **Reconstructive restoration** (or reconstructive regeneration) is an intervention strategy that involves reducing or eliminating the sources of degradation by acting on the activities generating the pressures, and taking action on the abiotic and biotic components of the ecosystem through the reintroduction of a significant proportion of species assemblages (biota).

It should be noted, however, that operations to optimise or maximise a site's significant production cannot be considered ecological restoration operations. These measures may themselves generate pressure on the ecosystem, as in the case of fish reefs, "living" deadweight moorings and "living" dykes.

Each restoration action follows the identification of the degradation of a site or an ecosystem. Following this, it is necessary to evaluate a reference state towards which progress should be made. The Society for Ecological Restoration (SER, 2004) uses the term "reference ecosystem", which it defines and analyses as follows: "a reference ecosystem", or "reference", can serve as the model for planning an ecological restoration project, and later serve in the evaluation of that project. This notion of reference must be clearly defined, as it can vary according to the time scale in question. A reference ecosystem dating back to prehistoric times and a reference ecosystem dating back to the 1980s will be quite different. Furthermore, current environmental conditions have changed considerably compared with those underlying historical reference states. These may therefore be unsuitable for contemporary and future ecosystems (Hobbs et al., 2014). It is advisable to enlist the help of several experts to define it. PatriNat (Laforge et al., 2024) states that the reference state (or "reference ecosystem" or "reference model") is: "a representation of a state that we want to re-establish or achieve at the end of the restoration process, chosen from several possible alternative states."

To move towards this reference state, it is necessary to define an ecological restoration strategy adapted to the target site and based on the following knowledge: the ecological state of the natural populations, the surrounding environment and as precise a diagnosis as possible of their state of health (Boudouresque et al., 2021).

It is also important to consider the current state of the degraded ecosystem. Depending on its degree of degradation and its resilience capacity in the face of various pressures, an ecosystem can cross a threshold qualified as a catastrophic transition (or regime shift).

The difficulty in reversing this transition (back to the previous stable state) despite a return to even very favourable environmental conditions is a phenomenon referred to as **hysteresis** (Kéfi 2012; Jones et al., 2018).
<figure><img src="image_4.png" /></figure>

Fault lined with clones in the Glénan Archipelago
© Benjamin Guichard/French Biodiversity Agency
Finally, the notion of environmental amnesia or shifting baseline syndrome is a concept to keep in mind when implementing a restoration strategy. Theorised in particular by biologist Daniel Pauly in 1995, it describes a gradual change in accepted societal norms regarding the state of the natural environment, due to a lack of information or experience of previous conditions. This is an important and impactful error of judgment on the reference condition of a site, leading to a degraded state being considered a good state. This is an important concept in restoration ecology. In fact, and particularly given the lack of knowledge of marine habitats, managers may feel compelled to maintain or restore an already degraded state. Many restoration projects do not aim to re-establish a natural balance but to maintain a state of balance in degraded mode. This hampers ecosystem resilience and deprives the management authority of the ability to act on the pressures. This is also the case for the restoration of native oyster reefs around the world; they were overexploited in the 18th and 19th centuries and are now the subject of a collective amnesia phenomenon that is erasing even the term 'oyster reefs' in habitat classifications and in our common language (Alleway and Connell, 2015; Pouvreau, 2023).

<caption>Posidonia meadow impacted by an underwater pipeline</caption>

© Antonin Guilbert/French Biodiversity Agency

<figure><img src="image_5.png" /></figure>

In 1995, Dr Daniel Pauly
coined the phrase
"Shifting Baseline Syndrome"

<figure><img src="image_6.png" /></figure>

Communities could re-set the ecological baseline IF they implemented "standards of practice" that restore a desired watershed condition. Achieving this would take time, commitment and perseverance.

Bend the Curve!

DECADES OR CENTURIES

Shifting baseline syndrome" theory by Daniel Pauly, 1995
# Ecological restoration in Europe

**There are few systematic reviews of restoration actions in Europe.** Nevertheless, as part of the European MERCES (Marine Ecosystem Restoration in Changing European Seas) project, Papadopoulou et al. (2017) have produced a state-of-the-art review of ecological restoration projects in the marine environment. The study identified 42 research projects carried out between 2007 and 2017.

The majority of these projects were carried out in Spain (24%), France (21%) and Italy (12%). The average duration of the projects surveyed was five years, and 45% focused on a single location. Only 17% involved transnational cooperation. Most of the projects (45%) were funded by the European Union, generally through the LIFE financial instrument, with an average budget of 3.5 million euros.

The study showed that methodological research (33%) was the most widely used method, followed by applied restoration (restoring a degraded habitat) (24%), then socio-economic enhancement

(14%) (increasing the value of goods and services). The most common method was species transplantation (21%), followed by seeding and planting (14%), artificial substrates (14%), hydrological modification and pollution removal (10% each). Lastly, the elimination of invasive species accounted for 5% of projects.

**This study demonstrated that restoration actions in Europe have focused mainly on seagrass beds (36%), followed by salt marshes (14%) and hard substrates/reefs (12%).**

However, the results of this study must be qualified. The methodology did not spell out the definition used to select projects. There may therefore be a bias with regard to "restoration" projects, demonstrating the importance of defining ecological restoration. Similarly, there is still some doubt whether the selected projects included natural, assisted and reconstructive restoration strategies.

<figure><img src="image_7.png" /><figcaption>Dead man's fingers (*Alcyonium digitatum*)
and *Tubularia (Tubularia larynx)*
© Emmanuel Donfut/French Biodiversity Agency</figcaption></figure>
# Legislative and regulatory framework for ecological restoration

## Key milestones

Historically, the fight against the decline of biodiversity has involved measures to protect species and natural areas. Ecological restoration has thus been able to develop with the help of regulations and policies at international, European and national levels.

In 1972, the United Nations Conference on the Human Environment put ecological issues on the international agenda for the first time. Twenty years later, 189 countries met at the Rio Summit and committed to the **Convention on Biological Diversity** (CBD, 1992), one of whose three objectives was the conservation of biodiversity. In 2014, the "**Convention on Biological Diversity**" (CBD, 2014) identified ecological restoration as a key action for maintaining essential ecosystem services (Aichi Biodiversity Target 14), with the target goal of restoring at least 15% of degraded ecosystems by 2020. In March 2019, the **United Nations** declared the decade 2021-2030 that of "ecological restoration" to combat global change and biodiversity loss, and improve food security by limiting the degradation and destruction of ecosystems. Finally, the current context (health crisis and recovery plan, latest IPCC report) highlights the urgency of rapidly developing measures to preserve and ecologically restore natural environments. The 15th **Conference of the Parties (COP15) was held in December 2022.** 196 signatory States adopted an agreement called the Kunming-Montreal Accord to establish a new "**Global Biodiversity Framework**". This historic framework aims to preserve nature and halt and reverse biodiversity loss, in order to put natural environments on the road to recovery by 2050. Twenty-three targets were selected for 2030, some of which represent significant progress compared with the 2021 draft agreement, and demonstrate the determination of States to make this new post-2020 Global Biodiversity Framework an ambitious agreement. These targets include at least 30% of areas of degraded terrestrial, inland water, coastal and marine ecosystems being under effective restoration (target 2) by 2030.

In Europe, one of the main driving forces behind the development of ecological restoration is the **1992 Habitats Directive** (Directive 92/43/EEC), which applied the commitments made at the Rio Summit that same year. Article 2 of this Directive states that EU Members must "**maintain or restore, at favourable conservation status, natural habitats and species of wild fauna and flora of Community interest**". This notion of favourable conservation status underpins the implementation of ecological restoration projects, either to improve it or when a plan or project is likely to significantly affect it. This directive, which complements the **Birds Directive** (Directive 2009/147/EC), will form

the basis of the **Natura 2000 network**. The main aim of these two directives is to ensure that the species and habitats concerned are maintained or restored to a favourable conservation status throughout their natural range within the European Union. The objective is not simply to halt their further decline or disappearance. It is important to ensure that species and habitats recover sufficiently to be able to flourish in the long term. The **Marine Strategy Framework Directive** (Directive 2008/56/EC) aimed to maintain or achieve good ecological status in marine waters by 2020. It extends the **Water Framework Directive** (Directive 2000/60/EC). In addition to improving the monitoring and knowledge of the state of the environment, these two directives also address the interaction of human activities and developments with coastal and marine ecosystems. They also mention the search for solutions to restore degraded environments. Lastly, to fulfil its commitments on the international stage, Europe launched the Green Pact in 2019 with the goal of achieving carbon neutrality by 2050. One of the founding pillars of this Green Deal is the restoration of nature, implemented in particular through the **Biodiversity Strategy 2030**. The strategy includes a number of actions, including the launch of the first-ever nature restoration law.

<figure><img src="image_8.png" /></figure>

© Emmanuel Rivas/French Biodiversity Agency
The impetus provided by these international and European policies has enabled France to adopt a number of measures to promote biodiversity conservation and the development of ecological restoration. This has been reflected in the transposition of the French Environment Code and the implementation of national strategies. Thus, following on from the 1976 Law on the Protection of Nature (Law no. 76-629), the **Law of 8 August 2016 for the Restoration of Biodiversity**, Nature and the Countryside (Law no. 2016-1087) aims to protect, restore and enhance biodiversity. The **National Biodiversity Strategy** (SNB) reflects France's commitment to the Convention on Biological Diversity. The SNB 2030 covers the years 2022 to 2030 and follows on from the first two strategies, which covered the periods 2004-2010 and 2011-2020 respectively. It aims to reduce pressures on biodiversity, protect and restore ecosystems, and bring about far-reaching chang-

es to reverse the trajectory of biodiversity decline. Also noteworthy are the **Documents Stratégiques de Façade** (DSF), which implement two European framework directives: the MSFD and **the Framework Directive for Maritime Spatial Planning (FDMSP)** (Directive 2014/89/EU). In February 2017, France adopted a National Strategy for the Sea and Coast (SNML), which is subsequently drawn up every six years. The DSF is a planning document that sets out the guidelines of this strategy. One of the 18 objectives of the SNML 2024-2030² is to achieve good ecological status and restore marine and coastal biodiversity.

Although these regulatory elements are not exhaustive, they highlight key elements of environmental law likely to motivate the development of restoration strategies.

# Adoption of a European Nature Restoration Regulation

## GENERAL OBJECTIVE

Against a backdrop of biodiversity collapse and climate change, the European Commission, as part of the EU's Biodiversity Strategy for 2030, has committed to setting up a regulatory framework with binding targets for nature restoration. This regulation aims to "put measures in place to restore at least 20% of the EU's land and sea areas by 2030, and all ecosystems in need of restoration by 2050."

It was proposed by the European Commission on 22 June 2022, then submitted to different phases of negotiation between the three European bodies in 2023. After several amendments, the text was finally adopted by the Council of the European Union on 17 June 2024, and published in the Official Journal of the European Union on 29 July 2024.

The general aim of this regulation is to restore degraded ecosystems throughout the EU (e.g. wetlands, forests, marine ecosystems, agro-ecosystems, rivers, lakes and alluvial habitats), in particular those with the most potential to capture and store carbon and to prevent and reduce the impact of natural disasters. Lastly, until 2030, Member States must give priority to Natura 2000 sites.

The European Regulation (EC, 2024) defines restoration as: "the process of actively or passively assisting the recovery of an ecosystem in order to improve its structure and functions, with the aim of conserving or enhancing biodiversity and ecosystem resilience, through improving an area of a habitat type to good condition, re-establishing favourable reference area, and improving a habitat of a species to sufficient quality and quantity in accordance with Article 4 (1), (2) and (3) and Article 5 (1), (2) and (3), and meeting the targets and fulfilling the obligations under Articles 8 to 12".

"Good condition" is defined as: "*a state where the key characteristics of the habitat type, in particular its structure, functions and typical species or typical species composition reflect the high level of ecological integrity, stability and resilience necessary to ensure its long-term maintenance and thus contribute to reaching or maintaining favourable conservation status for a habitat, where the habitat type concerned is listed in Annex I to Directive 92/43/EEC, and, in marine ecosystems, contribute to achieving or maintaining good environmental status*" (EC, 2024).

<footnote n="2">² https://www.mer.gouv.fr/sites/default/files/2024-06/strategie_nationale_mer_littoral_20242030.pdf</footnote>
This regulation covers several targets: terrestrial habitats of Community interest (Annex I of the regulation), species habitats (species listed in the HD, the BD and Annex III of the Regulation), marine habitats (Annex II of the Regulation), agro-ecosystems, river connectivity, urban ecosystems, pollinators and forest ecosystems.

## TARGETED MARINE HABITATS

Seven groups of marine habitat types (GHT) composed of lists of habitats according to the EUNIS 2022 habitat typology are considered:

<table><thead><tr><td>GHT</td><td>Wording of Appendix II of the Regulation</td><td>Proposed French translation</td></tr></thead><tbody><tr><td>GHT 1</td><td>Seagrass beds</td><td>Herbiers de phanérogames marines</td></tr><tr><td>GHT 2</td><td>Macroalgal forests</td><td>Forêts de macroalgues</td></tr><tr><td>GHT 3</td><td>Shellfish beds</td><td>Agrégation de bivalves</td></tr><tr><td>GHT 4</td><td>Maerl beds</td><td>Bancs de maërl</td></tr><tr><td>GHT 5</td><td>Sponge, coral and coralligenous beds</td><td>Biocénose d'éponges, corail et coralligène</td></tr><tr><td>GHT 6</td><td>Vents and seeps</td><td>Sources hydrothermales et suintements froids</td></tr><tr><td>GHT 7</td><td>Soft sediments (not deeper than 1000 metres of depth)</td><td>Sédiments meubles (jusqu'à 1000 m de profondeur)</td></tr></tbody></table>

The Regulation (Annex II of the Regulation) proposes a link between these GHTs and habitats of Community interest (HCIs). An extract from this Annex is contained in Annex 1 of this document. It should be noted that, although there is overlap between HCIs and GHTs, there is no strict equivalence between these units.

In parallel, the proposed Regulation (Article 5 §5) also targets the habitats of marine species:

* Terrestrial and marine species in Annexes II, IV and V of the HD,

* Land and sea bird species covered by the Birds Directive,

* 23 marine species (elasmobranchs and amphihalins) presented in Annex 2 of this note.

In addition to determining the areas to be restored and implementing restoration measures, the Member States will also have to identify and monitor the different habitats to be restored.
## EXTRACT FROM ARTICLE 5 ON THE MARINE ENVIRONMENT

### "Article 5 - Restoration of marine ecosystems

1. Member States shall put in place the restoration measures that are necessary to improve to good condition areas of habitat types listed in Annex II which are not in good condition. Such restoration measures shall be put in place:

a - by 2030, on at least 30% of the total area of groups 1 to 6 of the habitat types [...] that is not in good condition [...],

b - by 2040, on at least 60% and, by 2050, on at least 90% of the area of each of the groups 1 to 6 of the habitat types [...] that is not in good condition [...],

c - by 2040, on at least two thirds of the percentage referred to in point (d) of this paragraph of the area of group 7 [...] that is not in good condition, [...]; and

d - by 2050, on a percentage, identified in accordance with Article 14(3), of the area of group 7 of the habitat types [...] that is not in good condition, [...].

2. Member States shall put in place the restoration measures that are necessary to re-establish the habitat types in groups 1 to 6 [...] in areas where those habitat types do not occur, with the aim of reaching the favourable reference area for those habitat types. Such measures shall be in place on areas representing at least 30% of the additional surface needed to reach the favourable reference area for each group of habitat types, [...] by 2030, on areas representing at least 60% of that surface by 2040, and on 100% of that surface by 2050.

<figure><img src="image_9.png" /></figure>
3. By way of derogation from paragraph 2 of this Article, if a Member State considers that it is not possible to put in place restoration measures by 2050 that are necessary to reach the favourable reference area for a specific habitat type on 100 % of the surface, the Member State concerned may set a lower percentage at a level between 90 % and 100 % in its national restoration plan [...] and provide adequate justification [...]. In such a case, the Member State shall gradually put in place restoration measures that are necessary to achieve that lower percentage by 2050. By 2030, those restoration measures shall cover at least 30 % of the additional surface needed to achieve such lower percentage by 2050, and by 2040, they shall cover at least 60 % of the additional surface needed to achieve such lower percentage by 2050.

4. If a Member State applies the derogation pursuant to paragraph 3 to specific habitat types, the obligation set out in paragraph 2 shall apply to the remaining additional surface needed to reach the favourable reference area of each group of habitat types listed in Annex II to which those specific habitat types belong.

5. Member States shall put in place restoration measures for the marine habitats of species listed in Annex III to this Regulation and in Annexes II, IV and V to Directive 92/43/EEC and for the marine habitats of wild birds falling within the scope of Directive 2009/147/EC [...].

6. The determination of the most suitable areas for restoration measures in accordance with paragraphs 1, 2 and 5 of this Article shall be based on the best available knowledge and the latest technical and scientific progress in determining the condition of the habitat types listed in Annex II to this Regulation and the quality and quantity of the habitats of the species referred to in paragraph [...].

7. Member States shall ensure that the condition is known of the following areas:

a - by 2030, for at least 50 % of the area distributed over all habitat types in groups 1 to 6 listed in Annex II;

b - by 2040, for all areas of the habitat types in groups 1 to 6 [...];

c - by 2040, for at least 50 % of the area distributed over all habitat types in groups 7 [...];

d - by 2050, for all areas of the habitat types in group 7 [...];

8. The restoration measures referred to in paragraphs 1 and 2 shall consider the need for improved ecological coherence and connectivity between the habitat types listed in Annex II and take into account the ecological requirements of the species referred to in paragraph 5 that occur in those habitat types.

9. Member States shall put in place measures which shall aim to ensure that the areas that are subject to restoration measures in accordance with paragraphs 1, 2 and 5 show a continuous improvement in the condition of the habitat types listed in Annex II until good condition is reached, and a continuous improvement of the quality of the habitats of the species referred to in paragraph 5, until the sufficient quality of those habitats is reached.

10. Without prejudice to Directive 92/43/EEC, Member States shall, by the date of publication of their national restoration plans [...], endeavour to put in place necessary measures with the aim of preventing significant deterioration of areas where the habitat types listed in Annex II to this Regulation occur and which are in good condition or are necessary to meet the restoration targets set out in paragraph 14 of this Article

11. Outside Natura 2000 sites, the obligation set out in paragraph 9 shall not apply to deterioration caused by:

a - force majeure, including natural disasters;

b - unavoidable habitat transformations which are directly caused by climate change;

c - a plan or project of overriding public interest for which no less damaging alternative solutions are available, to be determined on a case by case basis; or

d - action or inaction by third countries for which the Member State concerned is not responsible.

12. Outside Natura 2000 sites, the obligation set out in paragraph 10 shall not apply to deterioration caused by:

a - force majeure, including natural disasters;

b - unavoidable habitat transformations which are directly caused by climate change;

c - a plan or project of overriding public interest for which no less damaging alternative solutions are available; or

d - action or inaction by third countries for which the Member State concerned is not responsible.

13. Within Natura 2000 sites, the non-fulfilment of the obligations set out in paragraphs 9 and 10 is justified if it is caused by:

a - force majeure, including natural disasters;

b - unavoidable habitat transformations which are directly caused by climate change; or

c - a plan or project authorised in accordance with Article 6(4) of Directive 92/43/EEC.
14. Member States shall ensure that there is:

a - an increase of the area in good condition for habitat types of groups 1 to 6 of the habitat types listed in Annex II until at least 90 % is in good condition and until the favourable reference area for each habitat type in each biogeographic region of the Member State concerned is reached;

b - an increase of the area in good condition for hab-
itat types of group 7 of the habitat types listed in
Annex II until at least the percentage, referred to
in paragraph 1, first subparagraph, point (d), is in
good condition and until the favourable reference
area for each habitat type in each biogeographical
region of the Member State concerned is reached;

c - an increasing trend towards the sufficient quality and quantity of the marine habitats of the species listed in Annex III to this Regulation and in Annexes II, IV and V to Directive 92/43/EEC and of the species falling within the scope of Directive 2009/147/EC."

NATIONAL RESTORATION PLAN (NRP)

To meet these objectives and fulfil their obligations,
Member States must present a **National Restoration
Plan** covering the period up to 2050, with intermediate
deadlines of 2030 and 2040. This Plan must be submitted
to the Commission within 24 months, i.e. by 18 August

2026 at the latest. This will be followed by a year of dis-
cussions with the Commission and the other Member
States, before final adoption on 18 August 2027. The Plan
may be revised every six years.

MILESTONES

<figure><img src="image_10.png" /></figure>
## Selection of feedback

LIFE IP MarHa is a European project designed to implement the Natura 2000 network at sea. Although there are many examples of actions similar to ecological restoration in overseas France, this note has chosen to present feedback from works and projects carried out solely in mainland France. They are presented by GHT targets as part of the nature restoration law.

Note 1: To our knowledge, no restoration actions are available for GHT 6 "Vents and seeps".

Note 2: The feedback presented here does not correspond to the definition in the strictest sense, but reflects the variety of projects identified as restoration projects. This technical note provides a critical analysis of these projects.

## Towards a critical analysis

To analyse the different projects, each "feedback" sheet includes a "Critical analysis" section based on the definition of restoration used in the Regulation (see definition on page 7).

This definition gives rise to a number of principles that will make it possible to validate the approach to these projects within the framework of the European Nature Restoration Regulation.

Thus, for a project to meet the definition of ecological restoration, it must:

1. (Target): start with a degraded ecosystem **AND**

2. (Target): consider all the components of an ecosystem, i.e. abiotic, biotic (considering communities representative of the ecosystem) and functional **AND**

3. (Target): aim for recovery (degraded state) towards a "known" reference state (of all components) **AND**

4. (Target): guarantee the long-term integrity of the ecosystem (without maintenance of restoration measure(s)) **AND**

5. (Method): define the initial state and qualify "degradation" **AND**

6. (Method): define the reference state of an ecosystem (justifying this choice) **AND**

7. (Method): identify the pressure(s) causing the degradation **AND**

8. (Method): be characterised by an intentional process **AND**

9. (Method): assess the level of intervention required to achieve the objective (choice of intervention strategy) **AND**

10. (Method): eliminate the pressures causing the degraded state OR reduce them to a level sustainable for the ecosystem OR prove that they no longer exist AND

11. (Progress towards the objective): monitor/confirm the recovery (state and/or surface) of all ecosystem components towards the reference state (demonstrate the effectiveness of the measure(s)/describe the ecological trajectory).

Where the following are understood as:

* Restoration target: all the different components of an ecosystem that have suffered degradation;

* Restoration objective: recovery of the ecosystem (all its components), taking as a reference a state intended to be re-established or achieved. This reference must be based on an integrated, functional "ecosystem model" that has been lost due to degradation.

* Restoration method: restorative process involving interventions to initiate or assist ecosystem recovery (ranging from interventions to limit pressures to a level sufficient for spontaneous ecosystem recovery, to actions on ecosystem components to assist recovery).
Comment 1: The approach applied here considers natural habitats. We do not consider here the specificities of restoring semi-natural habitats where ongoing/regular human activity is intrinsically linked to the dynamics/ balance of this semi-natural habitat (e.g. maintenance of lagoons and upkeep of their structure, maintenance of open terrestrial environments).

Comment 2: These criteria apply solely to this note, and are not a substitute for all the operational scoping work carried out to date, in particular by the SER. Their

purpose is to objectify this preliminary critical analysis for this study. They must be revised before they can be more formally implemented at national level.

Comment 3: If not all ecosystem components are targeted, and if not all pressures are lifted or controlled, but the other principles are respected, then the project can be considered a partial restoration action.

## Content of feedback sheets

Each project is presented in the form of feedback sheets, organised according to the following model:
# Project Title

Project implementation period:
Administrative project start and end dates

<figure><img src="image_11.png" /></figure>

00.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

GHT that can be targeted by the Nature
Restoration Law

### ECOLOGICAL ISSUE IDENTIFIED

Habitat or species at stake

### RESTORATION STRATEGY

Contribution to a possible restoration
strategy among natural restoration,
assisted restoration and reconstructive
restoration

### COSTS

Details of the costs accessed by LIFE
MarHa

### CONTACT

Contact for further information on the
project in question

## LOCATION

Geographical location of the project

<figure><img src="image_12.png" /></figure>

## Background and context of the approach

Presents the context in which the project was initiated.

## Nature of the operations

Summarises the different project actions to which LIFE MarHa has had access, in
chronological order.

## Report by the project leader

The report by the project leader is independent of the Life MarHa report and its
critical analysis.

## Critical analysis

This is a critical analysis with regard to the definition (Part I.2) and criteria (Part II.2) of ecological restoration used in this note.

### Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td></td></tr><tr><td>All the targeted ecosystem components</td><td></td><td></td></tr><tr><td>Recovery objective</td><td></td><td></td></tr><tr><td>Long-term integrity</td><td></td><td></td></tr><tr><td>Initial state</td><td></td><td></td></tr><tr><td>Reference state</td><td></td><td></td></tr><tr><td>Identified pressures</td><td></td><td></td></tr><tr><td>Intentional process</td><td></td><td></td></tr><tr><td>Choice of intervention strategy</td><td></td><td></td></tr><tr><td>Pressure reduction/elimination</td><td></td><td></td></tr><tr><td>Monitoring</td><td></td><td></td></tr></tbody></table>

If at least one of the criteria is missing, the project does not meet the chosen definition of ecological restoration.

Where the colours correspond to the following qualitative values:

<table><tr><td>Criterion fully met in the project</td></tr><tr><td>Criterion partially met in the project</td></tr><tr><td>Criterion not considered in the project</td></tr></table>
Feedback by target GHT

<figure><img src="image_13.png" /></figure>
<figure><img src="image_14.png" /></figure>

# SEAGRASS BEDS

Eelgrass (Zostera marina)
© Livier Schweyer/French Biodiversity Agency
<figure><img src="image_15.png" /></figure>

## PROJECT IDENTITY

### TARGET GHT

Seagrass beds

### ECOLOGICAL ISSUE IDENTIFIED

Eelgrass *Zostera marina*

### RESTORATION STRATEGY

Contributes to the natural restoration strategy

### COSTS

The total expenditure on the ECONAV project (AMI de l'AAMP 2013-2019) was €73,436.48, broken down as follows:

* 25% for the sociological study,

* 44% for the 12 ecological moorings installed,

* 31% for project management and follow-up (salary costs).

Another source of funding for ecological moorings: Natura 2000 contract

### CONTACT

FBA/Morgane Remaud
morgane.remaud@ofb.gouv.fr

### LOCATION

ZSC FR5300023 "Archipel des Glénan" located south of the commune of Fouesnant in Finistère.

<figure><img src="image_16.png" /></figure>

## Background and context of the approach

The Glénan Archipelago is a natural site protected by various regulations (classified site, national nature reserve, biotope decrees, underwater hunting reserve, Natura 2000, etc.). It is also one of Brittany's leading nautical sites.

In addition to its appeal for pleasure boating and related activities (recreational fishing, water sports, etc.), the site is also a centre of significant and varied professional fishing activity. Lastly, the number of tourists visiting the site has been rising steadily over the years, mainly due to the arrival of passenger boats from the mainland.

To better reconcile these uses and the protection of the site, the commune of Fouesnant, as a Natura 2000 operator and port manager, decided to initiate a debate to promote econavigation in the Archipelago by involving users more; it won the AMI "Econaviguer dans une AMP" in 2014.

Since 2017, the commune of Fouesnant has been experimenting with the use of "innovative" moorings, whose aim is to limit the impact on eelgrass beds (*Zostera marina*), habitats found in large numbers on the "Glénan Archipelago" Natura 2000 site and particularly sensitive to the pressure caused by moorings, as the scraping of chains on the seabed causes their degradation.

## Nature of the operations

The ECONAV project had several components. Given the difficulties encountered during the implementation of the project, only the following actions were carried out:

* a sociological study to better understand the site and its users. Unfortunately, the study was not conducted correctly, due in particular to the fact that the number of interviews required was too small for the ethologist's starting date (23/100), and to a total lack of project ownership by the elected representatives, as a result of the overly conceptual nature of the study. However, this study improved knowledge of how local players perceive the Archipelago. The results of this study were used to define an effective communications strategy and optimise existing governance.

* experimentation with ecological moorings: two types of system were installed, depending on water depth: a system with an intermediate buoy for greater depths, and a system without an intermediate buoy for shallower waters. Both systems
featured chain-winding hawsers to reduce their abrasive action. As a result, 12 innovative moorings were installed in 2017 on the Beg Meil and Saint Nicolas des Glénan sites (La Pie and La Chambre). The success of these innovative systems has encouraged elected representatives to replace all traditional communal moorings with low-impact moorings. New mooring lines were installed between 2018 and 2022, making a total of 38 ecological moorings at Saint Nicolas des Glénan (25 at La Pie and 13 at La Chambre).

* a study of nautical activity, to change thinking on the environmental optimisation of port facilities and the organisation of the waterfront.

**Monitoring** was carried out at each of the three sites to assess the effectiveness of the innovative moorings (two innovative moorings, one conventional mooring and a reference point located in a nearby seagrass bed free from anchoring pressure).

<figure><img src="image_17.png" /><figcaption>Monitoring protocol implemented</figcaption></figure>

<figure><img src="image_18.png" /><figcaption>In shallow water with a retractable line</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>In shallow water with the subsurface float</figcaption></figure>

The monitoring protocol, shown above, was as follows:

In each study area, monitoring involved assessing the density of eelgrass (*Zostera marina*) beds near mooring points and comparing the estimated densities near different mooring systems. The "classic" mooring represents the "normal or conventional mooring" reference point. The point within the beds represents the reference point in the absence of impact.

## Assessment by the project leader

The results of the eelgrass bed monitoring carried out between 2016 and 2021 (2022 for Beg Meil) in the three sectors studied seem to confirm the benefits of innovative moorings compared with conventional moorings. Over the five years of monitoring, the average density of the beds at the innovative moorings was much higher than that observed under the conventional moorings.

However, these results must be put into perspective given that the densities of beds under the innovative moorings remained lower than those of the reference beds at the three monitoring sites.

The dives carried out did not reveal any scraping of the ends on the seabed, although the tidal conditions at the time of the dives were probably not the most favourable for observing this phenomenon (mid-tide, coefficient 57). In the future, to understand and optimise the behaviour of these mooring systems, a test dive should be planned at low tide with a high coefficient, to observe system behaviour when the water depth is at its minimum. This test is planned for the new Le Grand Large ZMEL at Pointe de Mousterlin, which was recently 100% fitted with innovative mooring lines.
It should be remembered, however, that many parameters influence the dynamics of the sea beds (hydro-dynamic and morpho-sedimentary conditions, sunshine, etc.) and that it can take several years for them to return to optimal functioning after being impacted for many years (four years at the Plougonvelin site monitored by the Parc Marin d'Iroise).

The results of these five years of monitoring confirmed the value of the system but did not allow an assessment of the entire eelgrass re-colonisation process under the innovative moorings.

Due to the considerable human and financial resources required, and the replacement of all the traditional moorings by innovative moorings, monitoring according to the initial protocol was phased out in 2021 and 2022. It was decided to change the monitoring objective on the Glénan Archipelago, to no longer focus on the efficiency of the moorings, but on the evolution of eelgrass health (OPHZ's protocol). The effectiveness of low-impact moorings is still being monitored at the recently equipped Mousterlin ZMEL.

## Critical analysis

<table><thead><tr><th></th><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td rowspan="10">Definition of ecological restoration</td><td>Degraded ecosystem</td><td></td><td>Marine eelgrass beds degraded by mooring.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Only part of the biotic component was targeted here: the eelgrass bed and its functional components, which are difficult to assess. The abiotic components were not targeted.</td></tr><tr><td>Recovery objective</td><td></td><td>The objective was to increase the density of the sea bed, but not to recover all its components.</td></tr><tr><td>Long-term integrity</td><td></td><td>For the moment, monitoring has not demonstrated the long-term integrity of this ecosystem.</td></tr><tr><td>Initial state</td><td></td><td>An initial state was identified, but it only concerned the spatialisation of the bed.</td></tr><tr><td>Reference state</td><td></td><td>The project compared the bed subjected to scraping pressure with a nearby reference bed. However, no specific reference condition was identified for the restoration of the eelgrass beds.</td></tr><tr><td>Identified pressures</td><td></td><td>The main pressure on the eelgrass beds is boat anchoring.</td></tr><tr><td>Intentional process</td><td></td><td>Initiative of the Natura 2000 site manager and local elected representatives.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>To reduce and control the pressure on the beds, it was decided to contribute to the natural restoration strategy by experimenting to modify the moorings in the sectors concerned.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>Reducing and controlling pressure by replacing innovative mooring systems that prevent chains from scratching the eelgrass beds.</td></tr><tr><td>Monitoring</td><td></td><td>Only the parameters of eelgrass bed density, leaf length and leaf width were monitored.</td></tr></tbody></table>

This project contributed to the natural restoration strategy for eelgrass beds, but did not fully meet the definition of ecological restoration.

Although a positive trend is emerging, it has not yet been demonstrated that the state of the impacted bed has returned to the ecological state of the reference beds. The monitoring of the bed is planned to continue using the OPHZ protocol and should be continued over the long term by including different ecosystem components.
# Experiment to restore degraded beds in the Thau Lagoon by removing disused pleasure boats

## Project implementation period 2022 - 2025

<figure><img src="image_20.png" /></figure>

02.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Seagrass beds

### ECOLOGICAL ISSUE IDENTIFIED

* Eelgrass Zostera marina
* Dwarf eelgrass Zostera noltii
* Fan mussel Pinna nobilis
* Long-snouted seahorse
* Hippocampus guttulatus

### RESTORATION STRATEGY

Contributes to a natural restoration strategy

### COSTS

The total cost of the project is €58,300 excluding VAT

### CONTACT

FBA/Mathilde Labbe
mathilde.labbe@ofb.gouv.fr

Sète Agglopôle Méditerranée/
Jean Marc Rajaut
jm.rajaut@agglopole.fr

Syndicat Mixte du Bassin de Thau/
Camille Pfleger
c.pfleger@smbt.fr

### LOCATION

ZSC FR9101411 "Herbiers de l'étang de Thau", in the commune of Frontignan, Hérault.

<figure><img src="image_21.png" /></figure>

## Background and context of the approach

The Ponton de la Bordelaise is the emblematic dive site of the Thau Lagoon, where people can admire an unusual underwater landscape and exceptional biodiversity, including the Fan mussel, the Long-snouted seahorse, seagrass beds and large numbers of sea slugs.

**This site suffers from historical (former landfill) and recurrent (macro-waste and ship groundings) degradation, which has physically damaged the marine ecosystem.**

The Syndicat mixte du bassin de Thau (manager of the Natura 2000 site) and Sète Agglopôle Méditerranée (anti-pollution intervention brigade), accompanied by the Biotope consultancy and supported by a group of partners and community divers, decided to set up a project to restore and decontaminate the Ponton de la Bordelaise site. This project was carried out with financial support from the French Biodiversity Agency (FBA), as part of the Life MarHa programme (LIFE 16 IPE FR001).

It is part of a national issue of managing and retiring end-of-life pleasure boats (ELPBs), which many MPAs are facing as a result of fleet ageing and abandonment. It should be noted that ELPB removal operations are not currently subject to impact assessment.

This initiative also reflects the unanimous desire of the public (supported by the Project Rescue Ocean association) and the site's diving community, as well as local players and public authorities, to take action to preserve the biodiversity of this site impacted by the presence of some twenty ELPBs and other macro-waste.

## Nature of the operations

The project is divided into four stages:

1. The design and application of a decision support grid for ELPB removal. The Biotope consultancy was commissioned to carry out this work. It is made up of four categories of indicators that provide information on the physical characteristics of the ELPB, the ecological sensitivity or nearby anthropic issue, and the technical feasibility of removal. Each indicator assessed can be weighted according to the site's specific challenges, and then the overall analysis is translated into a removal relevance index. This grid was applied to 24 ELPBs and underwater macro-waste.

2. Monitoring by naturalist divers was carried out before and after the work. At T-1 months, to update knowledge of the initial state of the environment, and at T+1
months, to observe any potential degradation related to
the work. Lastly, a follow-up at T+1 year will be carried out
to update knowledge and compare it with the site's initial
status. Monitoring involves searching for, counting, measur-
ing and locating several key species on the site, particularly
in relation to ELPBs: the Long-snouted seahorse, the Fan
mussel and the eelgrass beds (number, sex, size, behaviour
and positioning, specifically linked to ELPBs). For fixed or
less mobile species, such as the fan mussel or eelgrass beds,
monitoring will help to determine whether the avoidance-re-
duction measures implemented during the works phase have
been effective (e.g. the installation of an anti-sludge curtain
for abandoned, silted-up vessels nearby to be removed).
However, this study has improved knowledge of how
local players perceive the Archipelago. The results of
this study were used to define an effective communi-
cations strategy and optimise existing governance.
For these species and for seahorses, monitoring will make it
possible to determine whether the changes caused on the
site by the removal of the ELPBs have had any consequences,
and thus to validate or invalidate the results of the evaluation
grid developed. This first test will also make it possible to
adjust the parameters of this assessment tool and readjust
future removal operations on the site.

3. Extraction of ELPBs and macro-waste. The work took place in winter, in line with the biological calendar and the fishing and shellfish farming activities close to the site. Removal can be tricky and time-consuming, depending on the state of degradation and access to the ELPBs (note: on site, most are sunk, and on banks with bottoms of 0 to 4 m). After drying, ELPBs that have remained intact are transported to the approved treatment centre (recycling paid for by *APER). Degraded ELPBs are sent to landfill. The construction of an access road and a technical area was necessary to carry out the extractions by land. (*APER: national eco-organisation approved by the French Ministry of Ecological and Solidarity to manage the dismantling and recycling of end-of-life pleasure and sports boats)

4. Capitalisation and optimisation of the operation: press coverage, descriptive video, on-site information panel, feedback sheet, raising boat owners' awareness of their rights and duties as boaters, boat end-of-life procedures, and consolidation of the intervention strategy for this issue in the Thau Lagoon.

<figure><img src="image_22.png" /><figcaption>End-of-life pleasure boat sunk in Thau Lagoon</figcaption></figure>

© Xavier Rufray/Biotope

Report by the project leader

The construction of this project required a great deal of preparation: numerous preliminary studies, construction of the analysis grid, consultation meetings, boat ownership forfeiture procedures, estimation of the technical requirements for the work, preparation of an overland route and agreement with the owners. It took almost two years, mainly due to the administrative complexity of this type of operation and the involvement of a large number of players.

Given the ecological issues at stake, it was necessary to step
up the environmental studies and ecological supervision of
the worksite. These requirements had to be assessed on a
case-by-case basis.

The momentum generated enabled multi-stakeholder collabo-
ration that was essential to the project's success. Consultation
and support for the project was a key stage.

The February 2024 worksite was unable to remove all the ELPBs from the site (14 in six days). The final follow-up one year after the completion of the work (February 2025) will determine the next stage of the project. The extraction of sunk ELPBs is very costly (€3,700/ELPB on average for this project). Not to mention treatment, which was not systematically covered by APER (in the case of ELPBs broken up at the time of lifting). Before scheduling new operations, a decision will have to be made between State or local authority portage, as well as co-financing.

The site was also affected by other damage: 122 tyres counted
in the area and 11 pieces of macro-waste (boat parts, fridges
and ELPBs) and even car parts.

The site's divers and the FFESSM (French Federation of Underwater Sports and Studies) wanted to help restore the site: organisation of a citizen operation to clean up underwater and land-based macro-waste a few weeks later, which led to the collection of 75 tyres and several kilos of waste.
Although monitoring at T+1 months showed no disturbance linked to the removal works (presence of seahorses, Fan mussels intact, no regression of seagrass beds), another is expected in early 2025 to identify trends in ecosystem response. Regular monitoring will then be carried out by the diving clubs.

<figure><img src="image_23.png" /><figcaption>ELPB and macro-waste sunk in Thau Lagoon</figcaption></figure>

© Thomas Menut/Biotope

## Critical analysis

<table><thead><tr><th></th><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td rowspan="10">Definition of ecological restoration</td><td>Degraded ecosystem</td><td></td><td>Lagoon degraded by vessel abandonment, resulting in chemical pollution and a physical impact on habitats.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>The project sought to target all ecosystem components: biotic (representative fauna and flora), abiotic (linked in particular to the nature of the substrate) and functional (presence of functional habitats).</td></tr><tr><td>Recovery objective</td><td></td><td>Objective of conservation of target species and renaturation of beds.</td></tr><tr><td>Long-term integrity</td><td></td><td>This project is helping to improve conditions at the site, but further action is needed to remove and control all the pressures on the environment (existence of the Ponton, emergence of the blue crab).</td></tr><tr><td>Initial state</td><td></td><td>Although an initial assessment was carried out, it only concerned part of the ecosystem's overall components.</td></tr><tr><td>Reference state</td><td></td><td>The aim of the project is to help restore a Mediterranean coastal lagoon (vegetated unconsolidated sediments).</td></tr><tr><td>Identified pressures</td><td></td><td>One of the pressures weighing on this ecosystem is the abandonment and subsequent degradation of pleasure boats and the accumulation of macro-waste. This leads to a degradation in the nature of habitats and their functions.</td></tr><tr><td>Intentional process</td><td></td><td>An initiative by the Natura 2000 site manager and a strong public commitment.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>Contribution to the strategy of natural restoration through the removal of pressures, using a grid to assess the potential ecological gain or loss from the removal of ELPBs. The choice of strategy was drawn up in consultation with all site stakeholders (scientists, socio-economic players, manager, local elected representatives and government departments).</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The very essence of the project is to reduce and help eliminate the pressures on the site. The aim is to eliminate all current and future pressures through the introduction of a regulation prohibiting mooring and berthing in the area. Other pressures remain poorly characterised, such as water quality and the presence of invasive exotic species.</td></tr><tr><td>Monitoring</td><td></td><td>Only part of the biotic component of the ecosystem is monitored: the species at stake.</td></tr></tbody></table>

This project may contribute to a natural restoration strategy for the Ponton de la Bordelaise site and partially meets the chosen definition of ecological restoration. As part of a continuum of actions aimed at restoring the site (improving water quality, raising user awareness), it has helped to reduce and eliminate pressure on the site.
# Operation to remove more than 20,000 tyres from the Golfe-Juan

## Project implementation period 2015 - 2019

<figure><img src="image_24.png" /></figure>

03.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Seagrass beds

### ECOLOGICAL ISSUE IDENTIFIED

Posidonia Posidonia oceanica
Coralligenous beds

### RESTORATION STRATEGY

Contributes to a natural restoration strategy

### COSTS

The total cost of the project was €1,2 million:

* AFB: €1 million

* Michelin Foundation: €200,000

### CONTACT

FBA/Mathilde Labbe
mathilde.labbe@ofb.gouv.fr

### LOCATION

ZSC FR9301573 "Baie et Cap d'Antibes - Îles de Lérins",
in the communes of Antibes and Cannes in the Alpes-Maritimes Region

<figure><img src="image_25.png" /></figure>

## Background and context of the approach

Millions of tyres were immersed along the coast to create artificial reefs for fishing purposes, a common practice in the 1970s. Artificial reefs have always been used in many parts of the world. However, Japan is the world leader in terms of submerged volumes, with over 20 million m³, mainly for fishing purposes. The United States comes second, with over 1,000 sites, this time for recreational purposes. In Florida, nearly two million tyres were submerged off the coast of Fort Lauderdale in 1972, at the suggestion of the American tyre company Goodyear. Once this had been recognised as a failure, a tyre removal operation was carried out between 2007 and 2010. France relaunched the principle in 1968, particularly on the Mediterranean coast, to increase fish stocks. A number of used materials were recycled to achieve this, such as electricity pylons, concrete stairwells, wrecks and, later, tyres. There are currently 90,000 m3 of artificial reefs off the coast of France.

Between 1980 and 1989, over 20,000 tyres (i.e. 8,000 m³) were immersed in the Golfe-Juan at a depth of between 24 and 37 m. The "Baie et Cap d'Antibes - Îles de Lérins" Natura 2000 site is located between Cannes and Antibes. At the time, the Direction Départementale de l'Equipement and the Prud'homie Services were hoping to support professional fishing in a fish-poor area. Nearly 30 years later, it has been a failure. Not only were these artificial reefs never colonised, but the tyres gradually disintegrated, releasing heavy metals into the water and spreading, threatening sensitive habitats in the vicinity (Posidonia meadows, coralligenous).

In 2015, a pilot tyre removal operation was carried out on a small scale. 2,500 tyres were removed (around 10%). This test phase validated the technical and environmental feasibility of the operation and enabled recommendations to be formulated for the second stage of the project, which involved the removal of the remaining tyres.

The operation to remove the artificial reefs, made up of over 20,000 tyres, had four main objectives:

* interrupt the process of altering the ecosystem and habitats of Community interest, such as the Posidonia meadow;

* consolidate the balance of this ecosystem to preserve it;

* restore the ecosystem to its natural state and functions;

* free the seabeds from the extensive occupation caused by the spreading of tyres by swell and currents.
## Nature of the operations

The tyre removal operation was subject to various regulatory procedures (case-by-case examination, project subject to declaration under the French Environmental Code, prior declaration and declaration concerning the occupation of the Public Maritime Domain).

The operation then took place over seven six-day campaigns at depths ranging from 25 to 35 metres, involving a team of six to eight professional divers.

### 1. Preparatory phase

Delivery of tyre storage containers and installation of skips on the vessel. D -4/5 days: Briefing of teams on the course of the project and positioning of underwater probes on the vessel.

### 2. Operational phase:

The day before work started:

* Positioning of the vessel in the area with the installation of four moorings on a sandy-muddy substrate, in order to define the work area;

* Deployment of a 150-metre anti-pollution barrier (securing the intervention zone and potential pollution);

* Environmental monitoring by Suez to ensure the effectiveness of the preventive measures before, during and after the works phase (monitoring of water quality, sedimentation and turbid plume).

Removal work:

* The divers grouped tyres in batches of 10 to 30 units on a rope;

* The batches of tyres were lifted by parachute, then crated on board the ship (after draining over water) and placed in containers;

* The divers collected other waste (scrap metal, macro-waste) in nets spread on the seabed and then hauled aboard;

* Surface collection of macro-waste for the duration of the worksite ("clean boat").

Waste treatment (tyres and others):

* Sea transport (Océa vessel) and regular unloading of skips in the port of Nice during the sea work (six trips for a total of 8,500 tyres);

* Treatment of tyres by Suez, without additional cleaning (reduction in water use and eco-responsible behaviour);

* 100% reuse of tyres (shredded and transformed into aggregate) at the Istres land-based site (Bouches-du-Rhône).

Marine restoration pilot project

© Greg Lecoeur/French Biodiversity Agency

<figure><img src="image_26.png" /></figure>

## Report by the project leader

Prior to the environmental monitoring of the site by Suez Environnement, a scientific assessment was carried out by the University of Nice Sophia Antipolis (under contract with the AFB). The main question was whether the partial removal of tyres in May 2015 had any impact on the marine environment and the health of organisms living in the environment. If so, what were the physiological and spatial-temporal consequences on the mussels caged at the study stations, chosen specifically for their location? **The results showed a negative impact on mussel survival, which diminished after 170 days, but no dispersal of pollutants to neighbouring sites.**

The environmental monitoring of the marine works demonstrated the absence of any impact on the physical, chemical or biological quality of the marine environment. In addition, an ROV tracking survey confirmed that almost all the tyres had been removed, with only a few scattered or completely silted up tyres remaining. It also helped to bring local players together and establish a common dialogue around the theme of marine environment rehabilitation. Raising public awareness through the different communication tools developed as part of this project has also increased recognition among local communities of the importance of protecting the marine environment, and encouraged them to take an active role in this protection.

A total of 20,553 tyres weighing 170 tonnes were removed.

This project made it possible to:
* interrupt the process of altering the ecosystem and habitats of Community interest, such as the Posidonia meadow, and consolidate the balance of this ecosystem in order to preserve it,

* restore the ecosystem to its natural state and functions before the immersion of the tyres,

* free the seabeds from the extensive occupation caused by the spreading of tyres by swell and currents.

<figure><img src="image_27.png" /></figure>

Marine restoration pilot project

© Greg Lecoeur/French Biodiversity Agency

## Critical analysis

### Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Physical and chemical pollution caused by the massive immersion of tyres.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Representative biotic and abiotic components were targeted in this project, but the functional components are unknown.</td></tr><tr><td>Recovery objective</td><td></td><td>Objective to return to a state prior to tyre immersion</td></tr><tr><td>Long-term integrity</td><td></td><td>Although the meadow is beginning to show signs of recovery (four years after the end of the project), this action will only be effective if the site is monitored on an appropriate and ongoing basis.</td></tr><tr><td>Initial state</td><td></td><td>Although an initial assessment was carried out, it only concerned part of the ecosystem's overall components.</td></tr><tr><td>Reference state</td><td></td><td>The reference here is that prior to the massive immersion of tyres, but is not justified by a given ecological status.</td></tr><tr><td>Identified pressures</td><td></td><td>The main pressure on this ecosystem was the physical pressure resulting from the dispersion of tyres on Posidonia meadows and coralligenous beds. As they degraded, they also caused chemical pollution.</td></tr><tr><td>Intentional process</td><td></td><td>FBA initiative.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>Contribution to the natural restoration strategy for habitats of Community interest such as seagrass beds and coralligenous reefs by removing tyre piles.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>Removal and control of the main source of pressure, but polluted sediments were not treated.</td></tr><tr><td>Monitoring</td><td></td><td>The project conducted a follow-up at T+212 days to demonstrate the effects of an initial experimental withdrawal of 2,500 tyres. There was no follow-up to the removal of the tens of thousands of remaining tyres.</td></tr></tbody></table>

This project can contribute to a natural restoration strategy for the ecosystem and habitats of Community interest (such as the Posidonia meadow) impacted by the immersion of over 20,000 tyres, and partially meets the definition of restoration. Posidonia meadows are priority habitats under the Habitats Directive, and have a slow growth rate (averaging between 100 and 1,000 cm per century), making their recovery particularly lengthy in the event of impact (Boudouresque et al., 2012). In addition, to validate the restorative scope of the project, it is necessary to carry out appropriate, long-term monitoring of the site (including the underlying sedimentary habitats), and protect the area from any form of pressure that could undermine the ecosystem's resilience.
# Restoration of dwarf eelgrass beds in the Arcachon Basin using the seeding method

## Project implementation period 2021 - 2022

<figure><img src="image_28.png" /></figure>

04.

FEEDBACK
SHEET

## PROJECT
IDENTITY

### TARGET GHT

Seagrass beds

### ECOLOGICAL ISSUE IDENTIFIED

Dwarf eelgrass *Zostera noltei*

### RESTORATION STRATEGY

Contributes to a reconstructive
restoration strategy

### COSTS

The total cost of the project was €14,300
including VAT, excluding HR costs:

* Services provided by teams from the Netherlands (equipment, transport and field work): €9,800 incl. VAT

* Cooler and small equipment:
  €4,500 incl. VAT

### CONTACT

Parc Naturel Marin du Bassin d'Arcachon
FBA/Thomas Fauvel
thomas.fauvel@ofb.gouv.fr

### LOCATION

ZSC FR7200679 "Bassin d'Arcachon et Cap Ferret",
in the commune of Gujan-Mestras in Gironde

<figure><img src="image_29.png" /></figure>

## Background and context of the approach

The world's seagrass beds are experiencing a major decline. In the **Arcachon Basin**, **84%** and **45%** of **common and dwarf eelgrass beds** respectively **have been lost since the 2000s**. The remaining areas are small and have largely lost their ecological functions. There are many reasons for their decline, but research by Ifremer has shown that it was initiated by contaminants whose toxicity is exacerbated by heatwaves and continues as a result of declining hydrodynamics. One of the objectives of the 2017-2032 management plan for the Parc naturel marin du Bassin d'Arcachon (PNMBA) is to restore seagrass beds to areas and ecological functions equivalent to those of the early 2000s.

The water quality and hydrodynamic conditions have now become favourable for the restoration of dwarf eelgrass beds on certain foreshores. The many assisted or reconstructive restoration experiments around the world have demonstrated that this method has great potential for recovering lost surfaces and functionalities. The conditions required for success are well identified: reduction of initial pressures (natural restoration), site selection and large-scale implementation. The pressures have been brought under control through awareness-raising campaigns for pleasure boaters and professionals, the removal of moorings on seagrass beds, support for the replacement of moorings with lower-impact devices, discussions and experiments with yachting and oyster farming professionals, and studies on pressures.

In this context, restoration by seeding seems to be the most appropriate option, given the wide availability of seeds, the absence of impact on donor meadows, the possibility of working on a large scale and the low cost.

Lastly, the simplicity of the protocol makes it possible to train and involve volunteer citizens, and to work on a very large scale, thus increasing the chances of success.

<figure><img src="image_30.png" /></figure>

<figure><img src="image_31.png" /></figure>

Colonisation CoI (%)

Decline in dwarf eelgrass area and coverage in the Arcachon Basin in 1989 and 2012 (Ifremer sources)
## Nature of the operations

The PNMBA maintained technical exchanges with teams from the University of Groningen and The Fieldwork Company, which are successfully implementing a project to restore intertidal seagrass beds by seeding in the Wadden Sea in the Netherlands. Their relatively simple method has been used since 2018, with the support of volunteers, in an area where seagrass beds had completely disappeared. By summer 2020, eelgrass could be observed within a 170 ha envelope around the seeding sites.

The Park was supported by teams from the Netherlands throughout the project. This operation involved four stages:

1. **Harvesting in summer/autumn 2021:** participants collected mature eelgrass breeding plants. These were then placed in water tanks until the seeds detached from the plant;

2. **Winter storage:** the 55,000 seeds, stripped of all organic matter, were stored in circulating cold water throughout the autumn and winter;

3. **Spring seeding:** the seeds were sown from March, just before the germination period. Seeding involves injecting a mixture of silt and seed directly into the sediment using an extruder gun;

4. **Follow-up:** this involved measuring germination rates in the laboratory and quantifying and measuring seagrass patches in the field.

<figure><img src="image_32.png" /><figcaption>Harvesting of breeding plants by participants
© PNMBA</figcaption></figure>

<figure><img src="image_33.png" /><figcaption>Beds from spring seeding
© PNMBA</figcaption></figure>

## Report by the project leader

**Though simple to implement, the method required few resources but a large workforce.**

It was shown that the probability of long-term success is highly dependent on the scale of the project.

Harvesting took place in August 2021 and seeding from March 2022. The volunteers were trained in the field by the PNMBA team.

Overall, seed storage was a success. However, the presence of mould was observed on the cuticle of a significant number of seeds (a fungus of the Halophytophtora genus).

In areas that seeds did not reach or that were not maintained due to currents, seeding just before germination could help to establish new seagrass beds. It would therefore be possible to initiate recolonisation in these areas or to reinforce regressing meadows to reverse the trend locally. Regular monitoring of the sites will enable the success of the operations to be assessed.

Initial field monitoring in July 2022 and laboratory germination tests showed encouraging results. However, monitoring carried out later in the summer failed to find the germinated eelgrass, which appeared to have been covered by the mud. According to observations on other seedlings by the Parc Naturel Marin, eelgrass does not form rhizomes (horizontal underground stems) in the first year, making it vulnerable to covering by mud.

A new monitoring operation, carried out on 19 July 2024 at Gujan Mestras, nevertheless revealed the presence of numerous patches of seagrass, ranging from 10 to 50 cm in diameter. An exhaustive study has not yet been carried out due to the significant presence of filamentous green algae, which covers a large part of the site. Further monitoring will be carried out at the end of the summer, as well as in another area where the seeds collected by the volunteers were sown in 2022.
Critical analysis

Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Seagrass bed in decline, which began in the early 2000s due to marine heatwaves and pollution, and continued due to its consequences on hydrodynamics.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>All the representative ecosystem components were targeted.</td></tr><tr><td>Recovery objective</td><td></td><td>Objective of returning to a state prior to the decline of the seagrass beds.</td></tr><tr><td>Long-term integrity</td><td></td><td>The eelgrass seeding project alone was not enough to guarantee the restoration of the beds. At the same time, other actions were taken to improve the conditions for returning to a reference state.</td></tr><tr><td>Initial state</td><td></td><td>Not all components were targeted, but the sites where these actions were carried out were known and the eelgrass had disappeared.</td></tr><tr><td>Reference state</td><td></td><td>The reference state targeted here was that close to the ecosystem of the 1980s.</td></tr><tr><td>Identified pressures</td><td></td><td>Seagrass decline was initiated by contaminants whose toxicity was exacerbated by heatwaves and continues as a result of declining hydrodynamics.</td></tr><tr><td>Intentional process</td><td></td><td>An initiative by the "Eelgrass" Commission of the Parc Naturel Marin du Bassin d'Arcachon (PNMBA), in response to the degradation of eelgrass beds.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>This project was part of an overall large-scale eelgrass restoration project. The strategy comprised a continuum of natural, assisted and reconstructive restoration actions.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>To make this possible, the PNMBA artificially modified the hydrodynamics of the area. Water quality was not yet optimal, but the PNMBA considers that the pressures have been sufficiently controlled to allow this action to be carried out. The project was combined with an assessment of any unidentified pressures.</td></tr><tr><td>Monitoring</td><td></td><td>The project was regularly monitored for changes in foreshore morphology, hydrodynamics and seagrass coverage.</td></tr></tbody></table>

The PNMBA drew up a strategy for restoring dwarf eelgrass beds based on five pillars: reducing anthropogenic pressures through management and support measures, acquiring knowledge of the regression phenomenon, a series of experiments to develop restoration tools, public awareness, and setting up international collaborations.

The single action of seeding presented in this sheet makes some contribution to the definition of ecological restoration. It should be stressed that this experiment is only possible if the hydrological conditions (a limiting factor in the case of eelgrass) are favourable.
# RenforC programme: strengthening carbon sinks in the marine environment

## Project implementation period 2021 - 2023

05.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Seagrass beds

### ECOLOGICAL ISSUE IDENTIFIED

Posidonia
Posidonia oceanica

### RESTORATION STRATEGY

Contributes to a reconstructive
restoration strategy

### COSTS

The cost of the operations to restore Posidonia meadows was estimated at approximately €200 per m²

### CONTACT

University of Corsica Pasquale Paoli
/Gérard Pergent
pergent_g@univ-corse.fr

/Christine Pergent Martini
pmartini@univ-corse.fr

### LOCATION

ZSC FR9402015 "Bouches de Bonifacio, Îles des Moines", in the commune of Bonifacio, Corsica

<figure><img src="image_34.png" /></figure>

## Background and context of the approach

Posidonia meadows, which cover more than 2 million hectares in the Mediterranean, store eight times more carbon than forest soils within the bio-constructed structure of their matte, which can be up to 8 m thick. Large quantities of carbon: 2,500 to 3,000 t CO2 equivalent per hectare are sequestered over several thousand years. In comparison, forests store 150 to 400 t CO2 equivalent per hectare.

As part of the Setec Foundation call for projects to combat climate change, the GIS Posidonia RenforC project was selected to launch a pilot project for the ecological restoration of these meadows. The Corsican Environment Office and the French Biodiversity Agency joined the initiative following this award. Several scientific teams were also identified to participate in this project, based on their expertise in the field of seagrass restoration: THALASSA Marine Research & Environmental Awareness (France), Biosurvey (Italy), University of the Balearic Islands - IMEDEA (Spain), International School for Scientific Diving (ISSD) "Anna Projetti Zolla" (Italy).

The RenforC programme aimed to develop and validate a strategy for reinforcing carbon sinks in the marine environment by setting up an experimental pilot project for the Posidonia meadow in Sant'Amanza Bay. The aim was to test different strategies (conservation, natural recolonisation) and restoration methods (fixation techniques, cuttings) for degraded seagrass beds at a single work site, and to assess their ecological and financial costs, in an attempt to restore the ecosystem services they provide as quickly as possible.

## Nature of the operations

Four transplantation techniques were tested on a single site in Sant'Amanza Bay. It was composed of dead matte due to the degradation of the beds by the anchoring of large pleasure craft.

<figure><img src="image_35.png" /><figcaption>Transplanting area</figcaption></figure>
In all, more than 12,000 Posidonia samples were collected by scuba diving in a nearby site, at an equivalent depth, with a minimum spacing of 2 m between plants to avoid damaging the existing meadow. These cuttings were preserved in seawater and attached to different supports before being planted on the experimental site at a depth of 15 m.

1. **THALASSA Marine Research & Environmental Awareness (France) transplantation pilot protocol:** Plagiotropic cuttings with 3 to 5 leaf fascicles were attached to galvanised steel stakes and then fixed to the substrate underwater, over an area of approximately 225 m² in seven islands of 3 m² with a high density equivalent to the adjacent unimpacted meadow (200 plants per m²), i.e. over 4,400 plants.

2. **Protocol of the University of the Balearic Islands - IMEDEA (Spain):** The cuttings were secured by U-shaped iron stakes and then fixed to the substrate underwater, over an area of approximately 225 m², in 24 islands of 1 m² with a lower density than that of the adjacent unimpacted meadow.

3. **Biosurvey (Italy) transplantation protocol:** The cuttings were attached to five-branch modules 75 cm in diameter over an area of 225 m². These modules were made from bioplastics derived from starch and vegetable oil. Their biodegradability was five years.

4. **International School for Scientific Diving (ISSD) (Italy) transplantation protocol:** The cuttings were placed on a coir mat previously fixed to the substrate.

The reference state for the transplantation site and the natural site were assessed in June and September 2021 respectively. Annual monitoring following the transplants took place in 2022 and 2023.

## Report by the project leader

The table below summarises the main results obtained.

<table><thead><tr><th></th><th>Protocol 1<br>Thalassa<br>mr&amp;ea</th><th>Protocol 2<br>UBI -<br>IMEDEA</th><th>Protocol 3<br>Biosurvey -<br>UNIPA</th><th>Protocol 4<br>ISSD -<br>UNISS</th></tr></thead><tbody><tr><th>Cuttings<br>survival rate</th><td>85 %</td><td>99 %</td><td>96 %</td><td>80 %</td></tr><tr><th>Bundle surviv-<br>al rate</th><td>83 %</td><td>85 %</td><td>71 %</td><td>96 %</td></tr><tr><th>Coverage</th><td>-42 %</td><td>-69 %</td><td>-67 %</td><td>-40 %</td></tr><tr><th>Leaf length</th><td>+4 %</td><td>-4 %</td><td>0 %</td><td>-19 %</td></tr></tbody></table>

Where the descriptors selected were:

* The survival rate of the cuttings corresponds to the number of living cuttings at time Tn (with n representing the time elapsed since the initial transplantation), compared with the number of living cuttings measured in the initial state (TO);

* Density represents the number of bundles per unit area (generally per square metre; Pergent et al., 2008). This value is obtained by counting the total number of bundles on the surface occupied by the transplants and, if necessary, reducing this value to the square metre (Monnier et al., 2021e) to facilitate comparisons;

* The transplantation coverage corresponded to the surface area covered by the cuttings in relation to the total surface area of the substrate on which they were planted; this descriptor was calculated from vertical photographs of the different transplants;

* The maximum canopy height corresponded to the length of the largest leaves in the leaf bundles, measured at the same time of year, i.e. in May (a parameter with marked seasonality). This descriptor was used to check whether the vegetative cycle of the transplants was influenced by the protocol.

According to the scientific experts in charge of the project, these reconstructive restoration techniques were more expensive than natural restoration techniques (pressure removal). These techniques can meet specific local needs, but cannot currently be applied on a large scale. An additional three-year monitoring project was initiated in 2024 to better understand the results of this comparison of techniques, and guidelines were drawn up in partnership with the Mediterranean scientific community and the FBA, to help restore Posidonia meadows. These guidelines can be downloaded from the MPN website (https://medposidonia-network.com/news/).

To guarantee the chances of success, the teams in charge of operating followed the recommendations issued by Boudourque et al. 2021, using the following decision tree:

<figure><img src="image_36.png" /></figure>
Critical analysis

Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Over the last few decades, the anchoring of pleasure craft in Sant'Amanza Bay has caused the loss of 8 ha of meadow, representing a 16% reduction in its surface area.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>The representative biotic component of the ecosystem was targeted in this project, but abiotic components were not mentioned. The project focused in particular on the specific function of carbon sequestration.</td></tr><tr><td>Recovery objective</td><td></td><td>The aim of this project was to test different experimental protocols for transplanting Posidonia to increase the surface area of the beds.</td></tr><tr><td>Long-term integrity</td><td></td><td>This pilot project aimed to demonstrate the effectiveness of different transplantation methodologies, but was not in itself sufficient to restore this habitat in Sant'Amanza Bay.</td></tr><tr><td>Initial state</td><td></td><td>Although an initial assessment was carried out between 2019 and 2020, it only concerned part of the ecosystem's overall components.</td></tr><tr><td>Reference state</td><td></td><td>The target reference here was the pressure-free state of the Sant'Amanza meadows, but no historical reference was targeted.</td></tr><tr><td>Identified pressures</td><td></td><td>The main pressure on this ecosystem was the anchoring of small and large pleasure craft within the meadow.</td></tr><tr><td>Intentional process</td><td></td><td>GIS Posidonia initiative in response to a call for projects.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>In view of past damage to the Posidonia meadow and the new protection measures, it was agreed to experiment with transplantation.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The main pressure from ships anchoring in the meadow was brought under control by the introduction of a prefectoral decree and the creation of mooring and light equipment zones (ZMEL) prohibiting all anchoring.</td></tr><tr><td>Monitoring</td><td></td><td>Follow-up work was carried out as part of the project, to demonstrate the effectiveness of the different methods to be tested.</td></tr></tbody></table>

Although this project could ultimately contribute to a reconstructive restoration strategy for the Posidonia meadow impacted by the anchoring of small and large pleasure vessels, it only partially meets the definition of restoration.

This experimental action aimed to re-establish the carbon sequestration function and was therefore akin to rehabilitation<fnref n="1" />. It differed from restoration, which aims to recover the ecosystem as a whole.

Posidonia meadows are priority habitats under the Habitats Directive, and have a slow growth rate (averaging between 100 and 1,000 cm per century), making their recovery difficult in the event of impact (Boudouresque et al., 2012).

<footnote n="1">¹ Rehabilitation is a process aimed at restoring specific functions of a degraded ecosystem (Le Floc'h & Aronson, 1995; Gann et al. 2019), restoring certain processes, productivity and certain ecosystem services (SER 2004). The objective of rehabilitation is therefore purely functional: the environment must be "fit" to perform a function that it is no longer able to do.</footnote>
MACROALGAL
FORESTS

Thongweed (*Himanthalia elongata*) in the Chaussée de Sein
© Yannis Turpin/French Biodiversity Agency
# Restoration of cystoseira belts
(Ericaria mediterranea and Gongolaria barbata)
by transplantation

## Project implementation period 2019 - 2021

<figure><img src="image_37.png" /></figure>

06.

FEEDBACK
SHEET

## PROJECT
IDENTITY

### TARGET GHT

Macroalgal forests

### ECOLOGICAL ISSUE IDENTIFIED

Gongolaria barbata
Ericaria mediterranea

### RESTORATION STRATEGY

Contributes to a reconstructive
restoration strategy

### COSTS

The total cost of the project
was estimated at €32,218 excluding VAT

### CONTACT

Aire Marine Protégée Côte Agathoise
Direction du milieu marin, Ville d'Agde
/Mélissa Trougan
melissa.trougan@ville-agde.fr
04.67.94.67.90

### LOCATION

Within the Aire Marine Protégée de la côte agathoise, Z
SC FR9101414: "Posidonies du Cap d'Agde",
off the commune of Agde in Hérault

<figure><img src="image_38.png" /></figure>

## Background and context of the approach

Cystoseirae are brown algae, known as "engineer species" as they structure their habitat to promote the development of a multitude of other organisms. Due to their arborescent morphology, cystoseirae form a habitat known as a "cystoseira forest". Cystoseira forests play an important role in the marine ecosystem: their structure allows juvenile fish to escape predators and to develop (this is known as a "nursery" zone). The Aire Marine Protégée (MPA) de la côte agathoise is a Natura 2000 zone covering 6,152 hectares of exclusively marine territory and managed by the town of Agde's marine environment department. Historically, several species of cystoseira have been recorded within the MPA: E. mediterranea, G. barbata, C. compressa and E. crinita. However, of these four species, two (E. mediterranea and G. barbata) have completely disappeared from the area since the 2000s. The main suspected causes of these disappearances are habitat destruction, water quality degradation, eutrophication and overgrazing by herbivores. Furthermore, the town of Agde's wastewater treatment plant, located close to the coast, was not designed to cope with the summer influx of visitors to the seaside resort, and much of the untreated water was discharged into the sea. In 2013, a new wastewater treatment plant opened and at the same time, water quality seemed to improve. These favourable conditions have led to the natural redevelopment of certain cystoseira (E. crinita and C. compressa). In this rather favourable context, the managers of the Côte Agathoise MPA decided to launch this project to restore the cystoseira belts of the species Gongolaria barbata and Ericaria mediterranea, whose transplantation techniques have previously been tested and validated by specialists from the Institut Méditerranéen d'Océanologie/GIS Posidonie in other areas of the Mediterranean.

<figure><img src="image_39.png" /></figure>

Installation of clusters of *Ericaria mediterranea* around the Ile de Brescou
© Mélissa Trougan/MPA agathoise
## Nature of the operations

The operation consisted of several main stages:

1. **The choice of transplantation site:** For both species, the transplantation areas were chosen taking into account exposure to hydrodynamics, bathymetry and the history of the presence of these species in Agde. It was therefore decided to reintegrate *G. barbata* at Brescou and La Roquille, and *E. mediterranea* at Brescou, Sentier sous-marin and Grande-Conque. For *E. mediterranea*, rocks were precisely identified according to their exposure, slope and immersion characteristics (bathymetry). Three rocks were identified at Grande Conque, two at Sentier sous-marin and five around Brescou. *E. mediterranea* was also planted under the eco-designed floating pontoon at Brescou, on porous concrete slabs.

An initial mapping of the presence of Cystoseira was carried out upstream of the Cystoseira reintroduction by surveying the rocky areas of the mediolittoral and upper infralittoral zones. Aerial photos were also taken using a drone to obtain an accurate aerial view of the shallow coastal waters.

2. **Transplantation of *Ericaria mediterranea*** - **July 2019:** The process applied was called Cystore™, which consists of taking fertile *Ericaria mediterranea* branches in spring-summer to make a "bouquet" that is then attached to the rock using a ring. This "bouquet" will emit zygotes (i.e. cystoseira "eggs") around the attachment point for two to three weeks. These bouquets will emit fractions of these zygotes and result in

young Cystoseira, known as "recruits", which will become fertile and initiate a gradual recolonisation from one area to the next. This method has already been tested on another species in Spain, *Gongolaria barbata* (Stackhouse) C. Agardh by M. Sales (in Gianni et al., 2013), and *Ericaria amenacea* in the Parc National des Calanques in Marseille (Javel et al., 2015). Branches were harvested in close proximity to limit the effects of maladaptation, and on belts spaced 2 m apart to avoid inbreeding.

3. **Transplantation of *Gongolaria barbata*** - **April 2019:** *Gongolaria barbata* was collected in the Etang de Thau near Balaruc les Bains. The process was identical to that used for *E. mediterranea*.

4. **Monitoring colonisation:** The evaluation of the project's success was based on the following monitoring:

* visual monitoring of the performance of transplants from year N and N+1 in spring and summer: visual observations with GIS reporting.

* visual PMT monitoring of cystoseira recruits and/or young plants every year in late spring, with a cartographic estimate of cystoseira colonisation dispersion.

<figure><img src="image_40.png" /><figcaption>*Ericaria mediterranea* recruit in November 2019
© MPA Agde</figcaption></figure>
<figure><img src="image_41.png" /><figcaption>Spring 2021 monitoring of one of the Mediterranean reintroduction stations © MPA Agde</figcaption></figure>

## Report by the project leader

In April 2019, shortly after the *G. barbata* plants were put in place, a sea storm washed almost all of them ashore. Following monitoring in October 2019 and June 2020, it turned out that the transplantation did not work, largely due to the sea storm.

The *E. mediterranea* transplants showed positive results, with the presence of recruits as early as autumn 2019, and in July 2020 in almost all the natural stations. For the time being, these young thallus are found in the immediate vicinity of the transplantation area, due to the low propagation capacity of zygotes of this species. **From 2020, annual PMT monitoring revealed effective colonisation from one site to the next on the majority of the implantation sites.**

At the Brescou Pontoon, the transplants positioned on the perforated concrete slabs did not work. The excessive depth of the slabs and the lack of light during the winter period, when the pontoon was wintered in the outer harbour of Cap d'Agde, were factors that greatly influenced the effectiveness of this operation. **So, in 2021, a new transplantation operation was carried out, but with the *G. barbata* species. However, this new operation proved unsuccessful.**

This study also allowed observation of the *E. crinita* population. This species is endemic to the Mediterranean and characterises an association that develops in a calm environment in the upper infralittoral zone. It structures the habitat of small rocky bottoms, harbours a high diversity of species and acts as a nursery for teleosts. It is a key species with a central functional role in food webs and in the photophilic infralittoral rock habitat. It would therefore be interesting to carry out a detailed mapping of macroalgal communities in the Côte Agathoise Marine Protected Area.

**From 2020, annual PMT monitoring revealed effective colonisation from one site to the next on the majority of the implantation sites.**

At the Brescou Pontoon, the transplants positioned on the perforated concrete slabs did not work. The excessive depth of the slabs and the lack of light during the winter period, when the pontoon was wintered in the outer harbour of Cap d'Agde, were factors that greatly influenced the effectiveness of this operation. **So, in 2021, a new transplantation operation was carried out, but with the *G. barbata* species. However, this new operation proved unsuccessful.**

This study also allowed observation of the *E. crinita* population. This species is endemic to the Mediterranean and characterises an association that develops in a calm environment in the upper infralittoral zone. It structures the habitat of small rocky bottoms, harbours a high diversity of species and acts as a nursery for teleosts. It is a key species with a central functional role in food webs and in the photophilic infralittoral rock habitat. It would therefore be interesting to carry out a detailed mapping of macroalgal communities in the Côte Agathoise Marine Protected Area.
Critical analysis

<table><thead><tr><th></th><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td rowspan="10">Definition of ecological restoration</td><td>Degraded ecosystem</td><td></td><td>Cystoseira forests were in decline due to a deterioration in water quality.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all ecosystem components were targeted in this action. Only part of the biotic component was targeted, notably two species of cystoseira.</td></tr><tr><td>Recovery objective</td><td></td><td>The primary objective of this action was to validate the effectiveness of the Cystoseira TM protocol and its replicability on the MPA site, with a view to the overall recovery of the ecosystem.</td></tr><tr><td>Long-term integrity</td><td></td><td>This experimental project aimed to demonstrate the effectiveness of different transplantation methodologies, but was not in itself sufficient to restore cystoseira belts.</td></tr><tr><td>Initial state</td><td></td><td>The site has been regularly monitored since 1982. A final initial assessment was carried out in 2019, prior to the transplantation operation.</td></tr><tr><td>Reference state</td><td></td><td>This pilot project aimed to test the replicability of a transplantation methodology and did not justify the notion of a targeted reference.</td></tr><tr><td>Identified pressures</td><td></td><td>Various pressures were identified as the cause of the decline in cystoseira belts: coastal artificialisation, poor water quality due to an obsolete wastewater treatment plant and overgrazing by herbivores.</td></tr><tr><td>Intentional process</td><td></td><td>MPA initiative.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>Water quality seemed to improve following a renovation of the wastewater treatment plant in 2013, leading to a return of certain cystoseirae. With the pressures under control, it was decided to use the transplantation method to target extinct species.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The main pressure came from water quality, which seemed to have been brought under control by the creation of a new wastewater treatment plant in 2013.</td></tr><tr><td>Monitoring</td><td></td><td>Monitoring was carried out as part of the project, but did not target all ecosystem components.</td></tr></tbody></table>

This experimental action may ultimately contribute to a reconstructive restoration strategy for two species of cystoseira: *Gongolaria barbata* and *Ericaria mediterranea* and partially meets the definition of ecological restoration.

Nevertheless, it was part of a continuum of actions whose overall ecological restoration challenge is described in the latest MPA management plan. The long-term objective was to restore the cystoseira belts historically present on the upper medio- and infralittoral levels of the MPA and thus recover the ecological functions of this habitat, particularly in terms of nursery and refuge zone.
<figure><img src="image_42.png" /></figure>

## PROJECT IDENTITY

### TARGET GHT

Macroalgal forests

### ECOLOGICAL ISSUE IDENTIFIED

*Laminaria hyperborea*

### RESTORATION STRATEGY

Contributes to an assisted restoration strategy

### COSTS

The total cost of the project is €156,900 including VAT over three years (Year 1: €82,600 incl. VAT, year 2: €39,900 incl. VAT and year 3: €34,400 incl. VAT)

### CONTACT

Association Estuaires Loire & Vilaine
President of the Association
/Jean-Claude Menard
jc.menard@club-internet.fr

## LOCATION

ZSC FR5202011 "Estuaire de la Loire nord" in the commune of La Baule, Loire-Atlantique

<figure><img src="image_43.png" /></figure>

## Background and context of the approach

Laminaria macro-algae fields are among the world's richest ecosystems. They are essential breeding habitats and nurseries for many species. They also provide essential ecosystem services by capturing part of the CO2 emitted by human activities and produce O2.

Although protected by the OSPAR Convention since 2021, the "Estuaires Loire & Vilaine" (ELV) association has noted the disappearance of *Laminaria hyperborea* from various sites in France. These sites include the Bay of Le Pouliguen, a site monitored by the association since 1995 (surface mapping study).

These disappearances are probably linked to excessive water turbidity and increased sediment deposition on the seabed. The causes may be natural, such as river flooding, but the Loire has been experiencing severe low water (the lowest average level of a river) over the last ten years, and no major floods have been reported. They are often man-made, due to harbour dredging. The port of Le Pouliguen/la Baule is dredged every two years, with discharges 500 m from the coast, and Pornichet every six years, with discharges into the bay at "Fromentières". There is continuous dredging of the Loire Estuary from Donges to St Nazaire using stationary dredgers and the direct discharge of 2 to 4 million tonnes into the estuary. In summer, the presence of phytoplankton blooms could be a factor in the opacity of the water column, thus reducing photosynthesis.

Kelp inventories enable the ecological assessment of water bodies (WFD (2000/60/EC) and the ecological quality assessment of coastal water bodies (Le Gal & Dernier-Courtel, 2015). ELV surface mapping shows that 90% of kelp has disappeared from Le Pouliguen Bay over the last 20 years, with the situation now stabilising.

ELV responded to a call for projects from the Loire Bretagne water agency and was selected to restore kelp habitats. The aim of this experimental project is to contribute to the restoration of 600m² of degraded areas by reintroducing kelp while taking action on the potential causes (harbour dredging). The îlots des Évens appear to be an ideal site for experimentation, for several reasons: the low water turbidity due to favourable currents, and an existing kelp population.
<figure><img src="image_44.png" /></figure>

Significant presence of mussels and starfish
during the definition of the initial state
© Armel Ruy - 1Ocean

<figure><img src="image_45.png" /></figure>

Laying of coir ropes
© Armel Ruy - 1Ocean

## Nature of the operations

### March 2023: Proposed actions on pressures

One of the causes of kelp disappearance is water turbidity, which reduces photosynthesis. This disrupts the recruitment and growth of kelp *Laminaria hyperbora*. The association identified this pressure as coming mainly from fine silt (clay) brought in by harbour dredging: Le Pouliguen/la Baule every two or three years, Pornichet every six years and occasional dredging of the Grand Port Maritime de Nantes-Saint-Nazaire in the estuary channel all year round. This represents between 40 and 60,000 tonnes of sediment. One of the project's first actions was therefore to meet port stakeholders and government departments to put forward recommendations for reducing the impact of dredging on kelp forests, in particular by adapting work schedules to the kelp cycle.

### November 2023: Kelp collection

Some 20 sexually mature specimens aged 4-5 years (1m long) were collected at several sites around the îlots des Évens. Some were then placed in basins at the Roscoff marine station, while others were placed in basins in Pénestin. The aim was to compare reproduction in controlled (Roscoff) and uncontrolled (Pénestin) environments.

### Winter 2023/2024: Kelp reproduction

Different supports (C. Weed protocol, Saint Malo) will be used at the Roscoff marine station and in a mussel farmer's tank in Pénestin. The composition of the îlots des Évens is highly varied. It is composed of boulders, rocks, small pebbles, large pebbles, small boulders and sandy areas. As a result, different supports were selected for the seedlings to adapt to the different types of habitat present. The supports were

four-strand coir ropes (to surround the blocks) or laid on the bottom, approximately 200 m long. Large stones 100/200 mm, placed at the bottom of the basins, flat rock slabs 30X40, 40X50 cm.

### Summer 2024: Kelp implantation

A range of players (ELV, diving clubs) implanted the young individuals on each dive. An initial survey was carried out over an area of 600 m²: fauna and flora inventory, site topography.

### From summer 2024: Monitoring

The evolution of the kelp (growth, any displacement of supports, recruitment) will be monitored for three years.

## Report by the project manager

This experimental work programme should help validate an effective methodology for contributing to the restoration of larger areas of kelp, as proposed in the "Seaforce" project submitted for European funding but not selected (Thibaut de Bettignies, PatriNat): restoration of 6 ha of endangered kelp forests and a reduction in identified anthropogenic pressures, while involving local stakeholders and the general public to ensure the sustainability of this approach. The overall aim of the work programme presented here is to provide a strong incentive for large-scale restoration to create a self-sustaining ecosystem by mitigating anthropogenic pressures and drawing inspiration from Nature-based Solutions (Ecological Services of Marine Ecosystems IUCN France, 2014).

<figure><img src="image_46.png" /></figure>

Example of a kelp forest in the Iroise Sea
© Yanis Turpin - French Biodiversity Agency
Critical analysis

Definition of ecological restoration

<table><thead><tr><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>ELV demonstrated a 90% disappearance of kelp over 20 years.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all ecosystem components were targeted in this action. Only part of the biotic and abiotic component were targeted.</td></tr><tr><td>Recovery objective</td><td></td><td>The aim of this project is to test a methodology for transplanting kelp plants to increase their colonised surface area.</td></tr><tr><td>Long-term integrity</td><td></td><td>This experimental project aims to demonstrate the effectiveness of a transplantation methodology, but does not in itself guarantee the restoration of the entire ecosystem.</td></tr><tr><td>Initial state</td><td></td><td>The site has been regularly monitored since the 1990s by ELV and as part of the WFD monitoring of water bodies. The variable conditions of this ecosystem also highlight the difficulty of carrying out a complete initial assessment.</td></tr><tr><td>Reference state</td><td></td><td>This pilot project aims to test the effectiveness of a transplantation methodology. The variable conditions of this ecosystem also highlight the difficulty of establishing a reliable reference state.</td></tr><tr><td>Identified pressures</td><td></td><td>The pressures have not yet been clearly identified. Episodes of mussel and brittle star invasion are frequent and demonstrate the real imbalance in the environment, due to both natural and anthropogenic causes (professional and recreational fishing). The main pressure identified by the association is an increase in turbidity due to dredging in the port of Le Pouliguen/la Baule. This results in an insufficient number of individuals needed to ensure good reproduction.</td></tr><tr><td>Intentional process</td><td></td><td>The association launched the project following the decline in kelp forests.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>As the number of individuals per m² was insufficient, it was decided to test a transplantation method.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>Discussions took place between ELV, port stakeholders and government departments before the start of the transplantation operations. To date, the pressures have not been brought under control.</td></tr><tr><td>Monitoring</td><td></td><td>Monitoring is planned over three years and will focus on the evolution of the kelp (growth, displacement or not of the supports, recruitment) as well as the physical and chemical quality of the water, to understand the pressures exerted on the environment.</td></tr></tbody></table>

This experimental action may contribute to a strategy of assisted restoration of the *Laminaria hyperborea* species on the ilots des Evens, but does not meet the definition of ecological restoration. This work is an experimental project aimed at testing a transplantation methodology to increase the kelp colonisation area, with a view to replicability at other sites. Although discussions have taken place with port stakeholders and government departments, the pressures that led to the decline in kelp are not yet fully known or under control.
# SHELLFISH BEDS

Common mussel (*Mytilus edulis*) and velvet crab (*Necora puber*)

© Emmanuel Donfut/French Biodiversity Agency
# FOREVER (Flat Oyster RECOVERy) project:
ecological restoration of the flat oyster
in Brittany

## Project implementation period 2018 - 2020

<figure><img src="image_47.png" /></figure>

08.

FEEDBACK
SHEET

## PROJECT
IDENTITY

### TARGET GHT

Shellfish beds

### ECOLOGICAL ISSUE IDENTIFIED

Flat oyster *Ostrea edulis*

### RESTORATION STRATEGY

Contributes to a reconstructive
restoration strategy

### COSTS

The total cost of the project was estimated at €1,388,363 excluding VAT, and it received EMFAF (European Fund for Maritime Affairs, Fisheries and Aquaculture) funding.

### CONTACT

Ifremer/Stéphane Pouvreau
stephane.pouvreau@ifremer.fr

### LOCATION

ZSC FR5300046 "Rade de Brest, Estuaire de l'Aulne", in the commune of Logonna-Daoulas in Finistère and ZSC FR5300027 "Massif dunaire Gâvres-Quiberon et zones humides associées" in Morbihan

<figure><img src="image_48.png" /></figure>

## Background and context of the approach

The project was divided into three phases:

1. **Inventory, map and study the dynamics of oyster beds** in Brittany. This work resulted in an inventory of residual populations, which is available for download (Pouvreau et al., 2021).

2. **Analyse**, from an ecological point of view, the essential elements involved in the dynamics of a wild flat oyster bed and their respective contributions to population recovery (recruitment, larval abundance, larval dispersal, predation, effects of abiotic parameters (temperature, salinity, etc.)).

3. **Undertake pilot tests** of ecological restoration (reconstructive) of *Ostrea edulis* using three types of method:

* **Shell enrichment:** This first type of action consists of depositing large, regular quantities of mollusc shells on the seabed, generally from the same family (*Ostreidae*, i.e. hollow oysters or flat oysters, etc.) or related families (*Scallops*, *Mytilidae*). These shells serve as an essential hard substrate for spat to attach to, and have the advantage of being chemically attractive to larvae (linked to calcareous compounds). However, as demonstrated in FOREVER, this technique can only be applied on calm bottoms and in areas with few predators;

* **Spat seeding:** This second type of restoration is relevant when the abundance of natural larvae is no longer sufficient. The sharp drop in larvae abundance recorded in Quiberon Bay in the 2010s led the SOBAIE oyster farming syndicate to ask all companies still engaged in flat oyster farming in Quiberon Bay to seed 1% of their annual harvest as spat on the central bank, a bank under collective concession in the centre of Quiberon Bay (concession awarded to the CRC de Bretagne Sud). The seeded spat come from the area: they are collected in summer using limed collectors, then lifted the following spring to recover the spat. Repeated every year, this type of action, which was monitored in FOREVER, can bring results, but requires very active predation control.

* **Creation and deployment of supports using innovative eco-design techniques (use of shellfish co-products) to support recolonisation (kickstarter).** This third type of technique, the most promising, was initiated in the FOREVER project. The eco-design of the support involved recycling hollow oyster shells into aggregates which, once mixed with cement, can be used to build specific structures. Nine reefs were submerged as part of this project. They consisted of between 40% and 60% shell debris, the remainder being cement. The larvae then colonised the reef. For this first-of-its-kind occurrence in France, the format of the reefs was decided in consultation with professionals.
## Report by the project leader

The inventory of populations carried out in Action 1 of the FOREVER project showed that it is rare to find populations subject to special management measures. This lack of

<figure><img src="image_49.png" /><figcaption>Artificial module installed during the FOREVER project at T0 - June 2019
© Ifremer</figcaption></figure>

management on a regional (and also national) scale was probably one of the ultimate causes preventing the species from making a significant comeback. To monitor the factors involved in the dynamics of a flat oyster bed (Action 2) and develop and test the restoration methods proposed in Action 3, underwater scientific experimental ecological restoration sites were implemented, starting in 2018, within the beds in each of the two workshop sites: the Roadstead of Brest and Quiberon Bay.

The results obtained after three years demonstrated the feasibility of restoration, at least on a small scale. The most effective method was to use suitable substrates. The first two fairly dense populations can now be seen on artificial reefs in the Roadstead of Brest and Quiberon Bay. Densities, aggregation levels and biodiversity place these populations at level 4 on the habitat assessment scale, equivalent to the "Oyster bed" level, the original habitat of the flat oyster. These reefs represent a very small surface area: 6 m² in Quiberon Bay and 3 m² in the Roadstead of Brest, but each now houses several hundred adult flat oysters. This demonstrates the relevance of this method. However, this first restoration project for the species in France also showed that a great deal of work remains to be done on the composition and design of these supports.

Launched in 2022, the REEFOREST project (REstoring the European Flat Oyster Reefs & their Ecosystem Services on the French coasts) will develop a material, a design and a method. This six-year project is the subject of an agreement between Ifremer and the FBA. It proposes to finalise and consolidate the restoration methodology (creation and deployment of adapted eco-nuclei) and to progressively implement the very first pilot ecological restoration operations for the species on different well-documented Natura 2000 sites for the species, relevant to the Life MarHa and able to serve as a textbook case in the future for other sectors of the French coast. The second objective of this

project is to test methodologies that can objectively measure the potential impact of restoration measures at targeted sites. In the Roadstead of Brest, the restoration of the oyster beds is interacting with another heritage habitat: the maerl beds.

While the REEFOREST project aims to optimise restoration methodologies, it also feeds into two other "transfer of scale" projects: REHPAR and CLIMAREST.

* Launched in 2024, the **REHPAR project** (Restoration of the Flat Oyster Beds in the Roadstead of Brest) is a multi-partner project funded by the Loire-Brittany Water Agency. It brings together the Comité Régional de la Conchyliculteur de Bretagne Nord, Ifremer and the Parc Naturel Régional d'Armorique. The aim is to restore a 200 m2 oyster bed using eco-designed modules made from *Ostrea edulis* reef wood on the Logona-Daoulas coastline. It will last one year and be the subject of long-term scientific monitoring. The eco-modules tested were developed as part of REEFOREST.

* The **CLIMAREST project** (EU Mission Horizon) is a European project running from 2023 to 2026 to restore different marine habitats in Europe, including the flat oyster in France. The main site is in Quiberon Bay, and the aim is to restore the former Penthievre oyster farm on a scale of several hundred m². The techniques used are those developed as part of REEFOREST.

<figure><img src="image_50.png" /><figcaption>Artificial module installed during the FOREVER project at T+15 months - September 2020
© Ifremer</figcaption></figure>
Critical analysis

Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Flat oyster reefs have all but disappeared from the workshop sites. The only remaining populations in Brittany are considered residual to fragile.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all ecosystem components were targeted in this project. Only part of the biotic component was targeted</td></tr><tr><td>Recovery objective</td><td></td><td>The FOREVER project aimed to re-establish high-density Ostrea edulis populations wherever possible.</td></tr><tr><td>Long-term integrity</td><td></td><td>The aim of this action was to test different methods that could contribute to reconstructive restoration, with a view to large-scale deployment. However, given the duration of the project, it was not possible to measure the long-term integrity of the ecosystem without restoration measures.</td></tr><tr><td>Initial state</td><td></td><td>One of the aims of the project was to inventory and diagnose the residual populations in Brittany (mapping and ecological state of the banks, physical and chemical parameters, associated biocenosis, genetic structuring and associated parasite status).</td></tr><tr><td>Reference state</td><td></td><td>In the absence of a convincing reference state at the start of the project, this notion was poorly defined. Since then, a major effort in historical ecology on a European scale and within the NORA framework has allowed a better definition of the reference (pre-industrial) state.</td></tr><tr><td>Identified pressures</td><td></td><td>Despite the species' decline, due in particular to overexploitation over several centuries, Brittany's relict populations are still subject to human pressures: dredge fishing, illegal dive fishing, shore gathering and habitat degradation.</td></tr><tr><td>Intentional process</td><td></td><td>NORA (Native Oyster Restoration Alliance) was created at the instigation of the OSPAR Commission, in response to the European-wide decline in flat oysters. The aim is to encourage the return of the flat oyster. On a national scale, this approach is provided by the FOREVER project.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>The obstacles identified by the project were the absence of natural supports, the presence of predators, the persistence of parasites, increased sedimentation and professional and recreational fishing. The project made it possible to test a number of different techniques and propose several possible strategies for reconstructive restoration only.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The experimental sites had pressures identified as causing the decline of flat oyster reefs (water quality, parasites). Only part of the pressures could be relieved in the current context. The first pressure (dredge fishing on relict populations) was no longer effective at the test site.</td></tr><tr><td>Monitoring</td><td></td><td>Monitoring was carried out throughout the project but did not take into account the entire ecosystem. Nevertheless, more comprehensive monitoring continues on projects arising from FOREVER (REEFOREST) over several years.</td></tr></tbody></table>

This action may contribute to a strategy of assisted restoration of the *Ostrea edulis* species and partially meets the definition of ecological restoration.

It laid the foundations for the restoration of this habitat: an initial assessment, an understanding of the ecosystem as a whole, an inventory of the pressures and recommendations for reducing them, as well as in situ tests to encourage recruitment with a view to initiating the recolonisation of this species.
<figure><img src="image_51.png" /></figure>

# MAERL BEDS

Maerl bed with *Lithophyllum fasciculatum*

© Alain Pibot/French Biodiversity Agency
# Removal of oyster-farming waste from a Maerl bed - Anse du Poulmic

## Project implementation period 2020 - 2021

<figure><img src="image_52.png" /></figure>

09.

## FEEDBACK SHEET

## PROJECT IDENTITY

### TARGET GHT

Maerl beds

### ECOLOGICAL ISSUE IDENTIFIED

Lithophyllum fasciculatum

### RESTORATION STRATEGY

Contribution to a natural restoration strategy

### COSTS

The total cost of the project was estimated at €59,335 excluding VAT:

* Habitat mapping (Biological coastal area):
  €11,250 excl. VAT

* Waste mapping operation (SERENMAR - SHIP AS A SERVICE):
  €10,715 excl. VAT

* Waste removal operation (including full recycling - SERENMAR):
  €29,370 excl. VAT

* Monitoring by the FBA: €8,000

### CONTACT

FBA/Alain Pibot
alain.pibot@ofb.gouv.fr

Parc Naturel Régional d'Armorique
/Anna Capietto
anna.capietto@pnr-armorique.fr

### LOCATION

ZSC FR5300046 "Rade de Brest, Estuaire de l'Aulne", in the commune of Argol in Finistère

<figure><img src="image_53.png" /></figure>

## Background and context of the approach

The Anse du Poulmic in the southern Roadstead of Brest is home to one of the world's few known stations (along with the Roz bank, also in the Roadstead of Brest, and Galway Bay in Ireland) of the habitat "Maerl banks with *Lithophyllum fasciculatum*" on mud. This Anse has long been known for its biological richness, used to collect the larvae of cupped oysters, flat oysters and scallops, notably due to its role as a "sink area".

Diachronic monitoring of the site since 2012 clearly showed the following trends:

* rarefaction of *Lithophyllum fasciculatum*, which was ubiquitous on this bank in 2012 but rare on the site in 2020;

* the modification of local hydrodynamics by obstructing the natural flow of currents causes over-sedimentation and an accumulation of free brown algae, leading to a lack of light that has had a major impact on the Corallinaceae species that make up the maerl;

* buoy deadweight moorings and the numerous materials, chains, ropes and other shellfish waste litter the benthic floor, generating scraping and crushing;

* finally, the flat oyster catchers and scallop cages obstruct the light on which the maerl species depend, over several hectares of this limited and heritage-rich site.

Despite this monitoring, the shellfish farming activities previously authorised on this site have generated large quantities of waste, causing significant damage and a clear degradation in the site's conservation state. The map below illustrates the importance of waste.

<figure><img src="image_54.png" /><figcaption>Mapping the maerl bed and associated waste</figcaption></figure>
## Nature of the operations

This project involved a number of different stakeholders, including government departments (DDTM, DREAL), the Natura 2000 zone manager, the Comité Régional de la Conchyliculture (Regional Shellfish Growing Committee) and two service providers: Bio-Littoral and SERENMAR - SHIP AS A SERVICE.

The project involved several steps upstream of the waste removal action:

* **August 2020:** mapping of benthic habitats in the Poulmic area (2,500 x 1,000 m). To achieve this, the consultancy firm produced 231 photographic and video points on a precise grid, using a weighted tripod fitted with two cameras and a spotlight;

* **November 2020:** diving and multibeam echosounder surveys to quantify and qualify the waste present;

* **March 2021:** waste extraction and transport to an approved sorting centre;

* **April 2021:** campaign to determine the density of *Lithophyllum fasciculatum* after obtaining authorisation from the site's professionals. The methodology used was the quadrat method along a linear transect.

<figure><img src="image_55.png" /><figcaption>Examples of waste removed during the operation</figcaption></figure>

© Alain Pibot/French Biodiversity Agency

<figure><img src="image_56.png" /><figcaption>Examples of waste removed during the operation</figcaption></figure>

© Alain Pibot/French Biodiversity Agency

<figure><img src="image_57.png" /><figcaption>Examples of waste removed during the operation</figcaption></figure>

© Alain Pibot/French Biodiversity Agency

## Report by the project leader

This project was part of an overall restoration strategy for the Anse du Poulmic maerl bed, which was the subject of three interventions: the removal of shellfish waste (2020 - 2021), the removal of underwater waste from the Lanvéoc-Poulmic naval base (2021-2022) and the adaptation of a shellfish concession to environmental challenges (2022 - 2025).

The cartographic study of 230 habitat stations (700 photos and 230 videos) revealed a high coverage of maerl beds with algal cover by the species *Rytiphlaea tinctoria*.

The second study highlighted high coverage rates of maerl beds in the shellfish park area.

It also demonstrated the importance of this site as a breeding ground for two species: the nudibranch *Doris verrucosa* and the black seabream *Spondyliosoma cantharus*.

The waste survey identified over 230 items of waste, mostly of oyster-farming origin. To fit in with the project budget, it was agreed to focus on waste larger than 1m² and located outside shellfish farming areas. **60 targets were removed as a result, representing almost 8 tonnes of waste.**

This operation allowed restoration work to be carried out on this rare habitat by removing waste (the greatest pressure on the site outside of active operation).

The changing health of the bank is monitored on a regular basis, making it possible to observe changes in its vitality and the range of associated species. However, there are clear signs of recovery in this habitat, with live maerl coverage approaching 100%. On the other hand, the specific species *Lithophyllum sp.* remains in a critical situation at this site.

This operation also made it possible to:

* raise public awareness of the richness of the Roadstead of Brest;

* make shellfish farmers aware of the damage caused by their practices;

* enter into discussions with shellfish farmers to transfer their activities to less fragile sites.
## Critical analysis

### Definition of ecological restoration

<table><thead><tr><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Decline in the vitality of maerl beds and associated biocenosis since 2012.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all components were targeted in this project; only the biotic components representative of this habitat and certain abiotic components were targeted.</td></tr><tr><td>Recovery objective</td><td></td><td>The project aimed to restore the general condition of the maerl bed in the Poulmic sector.</td></tr><tr><td>Long-term integrity</td><td></td><td>The aim of this action was to remove one of the main pressures (macro-waste abrasion) exerted on this site and allow the ecosystem to recover naturally. To date, it has not been demonstrated that this action alone is sufficient to guarantee the integrity of the ecosystem.</td></tr><tr><td>Initial state</td><td></td><td>The initial assessment carried out in 2020 enabled the area to be mapped, complementing the various inventories carried out previously. Not all ecosystem components were targeted.</td></tr><tr><td>Reference state</td><td></td><td>Only a reference state based on photographs from 2012 was targeted.</td></tr><tr><td>Identified pressures</td><td></td><td>A number of pressures were identified: the abandonment of shellfish waste, leading to physical and chemical pressure on the seabed, shellfish farming right on the maerl bed, and the deterioration in water quality in the Roadstead of Brest. It should be noted that this area was not subject to dredge fishing.</td></tr><tr><td>Intentional process</td><td></td><td>In 2018, the FBA initiated actions to halt the degradation of this habitat.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>In 2018, following the observation of the degradation of this heritage habitat, the FBA initiated discussions with various stakeholders in the area to establish a recovery strategy for this ecosystem: shellfish farming professionals, the State's instructive services and the Parc Naturel Régional d'Armorique (manager of the N2000 zone).</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The main thrust of this action was to reduce one of the main pressures on the maerl bank, but water quality was unassessed and uncontrolled.</td></tr><tr><td>Monitoring</td><td></td><td>BACI-type monitoring was carried out following the operations and will be continued in the coming years by the FBA and the N2000 zone manager, to demonstrate the effectiveness of pressure removal in this zone.</td></tr></tbody></table>

Following a mission to the area in 2012, it became clear that the site had a high environmental profile, including the presence of maerl beds rich in biodiversity. This heritage habitat was severely degraded in 2018. One of the targeted causes was the abandonment of shellfish waste. The aim of this action was to remove one of the apparent pressures and allow the ecosystem to regenerate naturally.

Although similar to remediation<fnref n="1" />, this action can contribute to a natural restoration strategy for the Anse du Poulmic maerl bank. In conjunction with the site's different stakeholders, it aimed to reduce or eliminate the sources of degradation by acting on the activities generating the pressures, and then allow the ecosystem to recover spontaneously. Furthermore, this operation was part of a continuum of restorative actions: adapting shellfish farming methods to environmental challenges, but also understanding and controlling the pressures originating in the watershed that lead to poor water quality through the TerraRade contract.

Although it meets certain principles of the definition, it is still premature and difficult to demonstrate the effectiveness of such an action on all ecosystem components. Monitoring must continue for several years, and the monitoring protocol must be refined.

<footnote n="1">¹ Remediation is a management activity consisting of eliminating or reducing the physical or chemical pollution of a site (e.g. removal or detoxification of contaminants or excess nutrients in substrate, sediment, water) (Gann et al. 2019).</footnote>
# Adaptation of a shellfish farm to environmental challenges

## Project implementation period 2022 - 2025

<figure><img src="image_58.png" /></figure>

10.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Maerl beds

### ECOLOGICAL ISSUE IDENTIFIED

*Lithophyllum fasciculatum*

### RESTORATION STRATEGY

Contribution to a natural restoration strategy

### COSTS

The breakdown of project costs is as follows:

* Replacement of four marker anchors: €6,920 incl. VAT

* Experimentation with natural catchment, production of raised cages: 50,000 incl. VAT

* Analysis of 420 photoquadrats: €18,900 excl. VAT

* Monitoring and boat rental: 9,000 excl. VAT

### CONTACT

FBA/Alain Pibot

alain.pibot@ofb.gouv.fr

Parc Naturel Régional d'Armorique
/Anna Capietto

anna.capietto@pnr-armorique.fr

### LOCATION

ZSC FR5300046 "Rade de Brest, Estuaire de l'Aulne", in the commune of Argol in Finistère

<figure><img src="image_59.png" /></figure>

## Background and context of the approach

A shellfish farm was authorised to operate for 35 years due to a lack of knowledge of marine habitats. Both concessions are located within the Natura 2000 site "FR5300046 - Rade de Brest, Estuaire de l'Aulne". This site boasts a marine habitat of high heritage value, the *Lithophyllum fasciculatum* maerl bed.

The Roadstead of Brest is a remarkable ecosystem for shellfish farming, with oyster beds (flat and hollow oysters) and spat collection activities. More recently, the emergence of an innovative activity based around the black scallop, *Mimachlamys varia* (hatchery and grow-out at sea), offers interesting diversification prospects for the industry.

The Roadstead is also home to vast maerl beds, some of which contain a very rare species: *Lithophyllum fasciculatum* or globular maerl (species in the process of being added to the list of national protected species). It is particularly present in the Poulmic - Lomergat sector, where scallop farming concessions are located. Farming is currently carried out in cages resting on the substrate, with an impact on the underlying habitat.

The project is led by Ferme Marine and financed by the Plan France Relance. The aim is twofold: to maintain economic activity on the site through new farming techniques, mainly at elevation, and to contribute to the natural restoration of the maerl bed by reducing pressure.

The results could make it possible to propose new operating methods and develop shellfish farming in areas that are currently inaccessible, as part of a sustainable approach to reconciling an economic activity with the preservation of heritage habitats. They will also lead to a more detailed understanding of this habitat. Lastly, the development of a new shellfish industry, that of the black scallop, meets the crucial challenge of diversifying the industry, with companies often in an economically fragile monoculture situation. They are exposed to zoo-sanitary hazards whose economic consequences can be dramatic.

<figure><img src="image_60.png" /></figure>

<figure><img src="image_61.png" /></figure>

Natura 2000 site
"FR5300046 - RADE DE BREST, ESTUAIRE DE L'AULNE"

<figure><img src="image_62.png" /></figure>

Maerl bank
with *Lithophyllum fasciculatum*

<figure><img src="image_63.png" /></figure>

Shellfish farming concessions

<caption>Project location in the Anse du Poulmic</caption>
## Nature of the operations

The project consisted of two major actions:

**1. Action 1 - Relocation and adaptation of breeding structures:**

* Adaptation of the technical process, by installing two raised cages to measure the height above ground, thus eliminating the impact of the cages on the maerl;

* Innovation through experimentation with natural scallop capture;

* Placement of four low-impact buoys to delimit the concession and reduce pressure on the habitat.

**2. Action 2 - Assessment of the impact and resilience of the natural habitat after the removal or reduction of the pressure:**

This action corresponds to monitoring the impact of Action 1. Quadrat photos (50 x 50 cm) of the area were taken before the installation of conventional and elevated cages to establish an initial state, and then at regular intervals to monitor the potential impact. All the images were then analysed by the Université de Bretagne Occidentale.

<figure><img src="image_64.png" /><figcaption>Photoquadrat - T0 cage D
© Alain Pibot/French Biodiversity Agency</figcaption></figure>

<figure><img src="image_65.png" /><figcaption>Photoquadrat - T+2 months,
under the cage
© Alain Pibot/French
Biodiversity Agency</figcaption></figure>

<figure><img src="image_66.png" /><figcaption>Photoquadrat - T+5 months,
under cage D
© Alain Pibot/French
Biodiversity Agency</figcaption></figure>

<figure><img src="image_67.png" /><figcaption>Algal cover of the photoquadrat in July 2023
© Alain Pibot/French Biodiversity Agency</figcaption></figure>

## Report by the project leader

**1. Action 1 - Relocation and adaptation of breeding structures:**

* Adaptation of the technical process, by installing raised cages to measure the height above ground, thus eliminating the impact of the cages on the maerl: The raised cages were due to be delivered to the shellfish farmer in spring 2023. During this period, the ironmongery business was in a state of flux, with significant recruitment difficulties. Despite contacting several companies specialising in the manufacture of shellfish farming equipment in rebar, they all withdrew several weeks after committing. These companies were suffering from shortages of staff, particularly welders. This caused several months' delay, forcing the Ferme Marine to adapt conventional cages by raising them according to plans drawn up at the end of 2022. They were delivered in July 2022. Prior to the installation of the two elevated cages, four conventional cages (placed on the bottom) were put into the water in October 2022 to monitor their impact.

* Innovation through experimentation with natural scallop capture using biosourced cups: Unfortunately, it was not possible, within the time available for this project, to build enough capture devices to initiate the offshore test phase. The lead times were too long.

* Placement of four low-impact buoys to delimit the concession and reduce pressure on the habitat: A service provided by TEMANO enabled the old buoys to be replaced by four ecological buoys in September 2022. Technical teams also took advantage of the sea outing to remove 1 tonne of oyster-farming waste.
## 2. Action 2 - Assessment of the impact and resilience of the natural habitat after the removal or reduction of the pressure:

The monitoring protocols for this action are available on request. The metrics used were the percentages of:

* live maerl,

* fauna,

* algae,

* crustose coralline algae,

* live maerl x dead maerl,

* live maerl x sediment,

* dead maerl x sediment,

* empty shells,

* empty shells x sediment

At the same time, different taxa typical of a good maerl state were sought.

105 photo quadrats were analysed over six outings between October 2022 and July 2023. Monitoring will be carried out in 2024 and 2025.

The results are still being analysed and will be available once the 2024 monitoring programme has been completed.

The project faced a number of challenges. The weather conditions made it impossible to take all the photos planned. In winter, swell and rainfall conditions made it difficult to apply the protocol, and in summer, heavy algal coverage in the Roadstead of Brest made this application impossible. In addition, the geo-political context has had repercussions

on the timescales and rates normally applied in cage design. This delayed the start of the experiment, forcing a revision of the initial protocol. Monitoring should therefore continue at least until 2024 and 2025. However, long-term monitoring would allow the true impact of this restoration project to be assessed.

<figure><img src="image_68.png" /><figcaption>Algal cover of the cages in July 2023
© Alain Pibot/French Biodiversity Agency</figcaption></figure>

<figure><img src="image_69.png" /><figcaption>Photoquadrat distribution diagram</figcaption></figure>
## Critical analysis

### Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>The breeding cages smother the maerl beds and the associated biocenosis.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all components were targeted in this project; only the biotic components representative of this habitat.</td></tr><tr><td>Recovery objective</td><td></td><td>The project aimed to restore the general state of the maerl bed within a shellfish farm concession.</td></tr><tr><td>Long-term integrity</td><td></td><td>The aim of this action was to control the main pressure (suffocation of shellfish cages) on this concession and allow the ecosystem to recover naturally. It has not yet been demonstrated that this action alone can be sufficient to guarantee the integrity of the ecosystem.</td></tr><tr><td>Initial state</td><td></td><td>The initial assessment carried out in 2022 enabled the area to be characterised, complementing the various inventories carried out previously. Not all ecosystem components were targeted.</td></tr><tr><td>Reference state</td><td></td><td>No reference state was targeted for this project.</td></tr><tr><td>Identified pressures</td><td></td><td>A number of pressures were identified: the abandonment of shellfish waste, leading to physical and chemical pressure on the seabed, shellfish farming right on the maerl bed, and the deterioration in water quality in the Roadstead of Brest. It should be noted that this area was not subject to dredge fishing.</td></tr><tr><td>Intentional process</td><td></td><td>In 2018, the FBA initiated actions to halt the degradation of this habitat.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>In 2018, following the observation of the degradation of this heritage habitat, the FBA initiated discussions with various stakeholders in the area to establish a recovery strategy for this ecosystem: shellfish farming professionals, the State's instructive services and the Parc Naturel Régional d'Armorique (manager of the N2000 zone).</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The main thrust of this action was to reduce pressures on the maerl bank, but water quality was unassessed and uncontrolled.</td></tr><tr><td>Monitoring</td><td></td><td>BACI-type monitoring was carried out following the operations and will be continued in the coming years by the FBA and the N2000 zone manager, to demonstrate the effectiveness of pressure reduction in this zone. Not all ecosystem components were targeted.</td></tr></tbody></table>

This experimental action can ultimately contribute to a natural restoration strategy for the Anse du Poulmic maerl bank. In conjunction with the site's different stakeholders, it aimed to reduce or eliminate the sources of degradation by acting on the activities generating the pressures, and then allow the ecosystem to recover spontaneously. This action also aimed to adapt shellfish farming to environmental challenges, while enabling economic activity on the site.

This operation was part of a continuum of restorative actions: removal of macro-waste, but also understanding and controlling the pressures originating in the watershed that lead to poor water quality through the TerraRade contract.

Although it meets certain principles of the definition, it is still premature and difficult to demonstrate the effectiveness of such an action on all ecosystem components. Monitoring must continue for several years, and the monitoring protocol must be refined.
# SPONGE, CORAL AND CORALLIGENOUS BEDS

Coralligenous beds, the Mediterranean's major ecosystem, and red coral (Corallium rubrum), which is particularly fond of rocky bottoms with little exposure to light
© Emmanuelle Rivas/French Biodiversity Agency
# Protecting coralligenous reefs at Cap d'Agde

## Project implementation period 2020 - 2022

<figure><img src="image_70.png" /></figure>

11.

## FEEDBACK SHEET

## PROJECT IDENTITY

### TARGET GHT

Sponge, coral beds and coralligenous beds

### ECOLOGICAL ISSUE IDENTIFIED

Coralligenous beds

### RESTORATION STRATEGY

Contributes to a global natural restoration strategy

### COSTS

* The total cost of the Récif lab project was €1.3 m (excl. VAT)

* Lot 4 of this project: the artificial reef village operation (studies and works) cost around **€700,000**. It was financed by ADEME (Ministry of Ecological Transition), the Occitanie/ Pyrénées-Méditerranée Region, the French government (Plan Littoral 21 Méditerranée) and the town of Agde.

### CONTACT

AMP côte agathoise
/Renaud Dupuy de la Grandrive
renaud.dupuy@ville-agde.fr

## LOCATION

Within the Aire Marine Protégée de la Côte agathoise, Z SC FR9101414: "Posidonies du Cap d'Agde", off the commune of Agde in Hérault

<figure><img src="image_71.png" /></figure>

## Background and context of the approach

Along with the Posidonia meadow, the coralligenous habitat is one of the two main habitats emblematic of Mediterranean biodiversity. Flora and fauna are extremely well represented, offering a vast palette of colours and a unique biological richness. Only present away from bright light, its development is very slow (1 to 4 mm/year). It is built by the accumulation of encrusting red algae on a rocky base, making it vulnerable to external, mainly mechanical pressures, such as recreational diving.

Within the Aire Marine Protégée de la Côte Agathoise (AMPCA), the Roc de Brescou fishing area was set up by the Ministry of Agriculture and Food decree of 27 December 2019, which prohibits all forms of fishing in this area. It was then supplemented by the prefectoral decree of 31 January 2020 to regulate ship mooring, scuba diving and dredging. Together, these two decrees form what is commonly referred to by the public, for the purpose of better understanding, as the Roc de Brescou marine reserve. Initiated by professional fishermen and supported by the town of Agde, this reinforced protection zone (ZPR) located less than 2 km off the coast of the Île de Bresco has the status of a fishing area for a renewable six-year period. Its regulations authorise navigation but prohibit all forms of professional or recreational fishing, scuba diving, ship mooring and dredging.

<figure><img src="image_72.png" /></figure>
The objectives were the following:

* protect natural habitats (the marine reserve covers rocky and sandy seabeds, as well as 46% of Agde's coralligenous reefs), and protect biodiversity including fish, molluscs and crustaceans...

* protecting biodiversity through this marine reserve supports sustainable fishing (both professional and recreational) and the sustainable management of scuba diving activities.

As a result, some coralligenous dive sites have been withdrawn from Adge diving, increasing pressure on the few remaining coralligenous spots outside the area.

## Nature of the operations

Initiated by professional fishermen, the creation of the Roc de Brescou Marine Reserve took place in several stages:

### 1. Consultation between local players

This stage brought together all the socio-economic players: professional fishermen, local elected representatives, recreational fishermen, managers and professional divers. The fishing area project was validated by the COPIL of the marine protected area in July 2018.

### 2. Administrative procedure:

A file was submitted to the DDTM-DML34 in October 2018. This followed a series of consultations and validations with various bodies (Ifremer, CPMR, local nautical commission, maritime prefect, DPMA CNPMEM and public consultation).

The reserve was finally subject to two decrees:

* the ministerial decree of 12/27/19 (NOR: AGRM1931952A), which stipulates that all forms of sea fishing are prohibited in the entire delimited area, for a period of six years (renewable).

* the maritime prefectural decree of 01/31/2020 (N° 007/2020) prohibits ship mooring, scuba diving (with scuba gear or free diving) and dredging in this zone.

In parallel with the area, the Côte Agathoise MPA led the RECIF'LAB programme (ADEME Programme d'Investissement d'Avenir), divided into four batches, with the common aim of proposing an innovative approach that integrates coastal and offshore issues for the recovery of biodiversity, while acting on the pressures and impacts associated with them. More specifically, lot 4 of this programme was dedicated to reducing the pressure on the coralligenous beds linked to the intensity of diving activity by implementing and managing an alternative offer: the immersion of a pressure relief device near a less sensitive site. To do this, a village of artificial reefs, created in consultation with the local diving community, was immersed on a soft bottom with low sensitivity, at the same bathymetry as the coralligenous beds and close to the fishing area.

### 3. Device design workshop and in-depth engineering studies

The village was designed in consultation with the diving community to meet both their expectations and the project's ecological objectives. Based on the ideas put forward by the centres, a technical and economic pre-study and detailed engineering studies (hydrodynamics, geotechnical stability, sizing of artificial reef elements, etc.) were carried out.

### 4. Administrative authorisations

A request for an amendment to the artificial reef concession was submitted to the DDTM-DML34 to obtain administrative authorisations for the immersion of artificial structures.

### 5. Manufacture, transport and immersion

The main module was assembled directly in the port of Sète (for direct access to the transport barge) using 3D concrete elements manufactured in the workshop. The secondary modules were manufactured in the workshop and placed on the barge with the riprap. The artificial village was immersed over three days in early July 2022. In all, a 3D-printed concrete main reef (6.5m high, with a 6m x 8m base) was immersed, surrounded by ten smaller secondary modules and a pile of riprap.

### 6. Management and operation of the device

A number of workshops took place with Adge divers to define the management methods. It was decided to provide free access to the site, with no mooring (to limit damage to the site) and restricted to one boat on site at a time, to avoid overcrowding. These rules were incorporated into the new Natura 2000 diving charter. A site access schedule has also been set up between the diving clubs.

### 7. Scientific monitoring

In accordance with the ministerial decree, and to assess the effectiveness of this protection measure, scientific monitoring was carried out before and after (n+3) the installation of the protected area. Various indicators were measured: project acceptability, coralligenous protection, assessment of fishery resources and biodiversity, assessment of catches by professional fishermen, visitor numbers and compliance with regulations and resources.

The installation of the artificial reefs required the following monitoring:

* monitoring of diving activity and ichthyological monitoring of the two habitats: the coralligenous bed and the artificial site, using a BACI-type methodology;

* monitoring of the physical condition of the structures and colonisation by underwater flora and fauna.

The monitoring is based on the strategy document for the implementation of artificial reefs, and is planned over a 12-year period (+1, 3, 6, 9 and 12 years).
# Evaluation

An evaluation of the fishing areas was carried out at mid-term (2023). The results are summarised below.

## Social criteria

### Project acceptability

100% of the users surveyed (professional diving organisations and associations, yachting associations, recreational fishing and spearfishing associations, professional fishing/tour boat organisations and prud'homie) considered the reserve to be an asset for the maritime territory of Agde and were in favour of maintaining it. 90% of the recreational anglers surveyed were aware of the reserve's existence, although 30% were unaware of its regulations and exact perimeter. Anglers' perception of the reserve is mixed, mainly due to the absence of markers in the area.

## Ecological criteria

### Coralligenous bed protection - currently being acquired

### Assessment of fishery resources

Experimental fishing was generally lower in 2022 than in 2019 for all zones combined, with the first significant effects on yield appearing in the ZPR Lobsters, brown scorpion fish and capons were more abundant in the ZPR. After visual counting, the density of six species was increasing: conger eel, lobster, rock lobster, rock scorpion fish, small red scorpion fish and rock red mullet.

### Biodiversity assessment

There was a trend towards increased density of Peysonnelia algae and erect bryozoans in the ZPR, and a slight decrease in Cliona drilling sponges in and outside the ZPR. Acoustic monitoring showed an increase in fish biophony within the reserve. This effect was not found on benthic invertebrates.

## Economic criteria

### Assessment of catches by professionals

No results presented, due to lack of data

### Visitor numbers

There was no change in the use of the area by divers, but recreational fishermen moved to the western sector, close to the reserve. Violations were a daily occurrence.

<figure><img src="image_73.png" /><figcaption>Spiny lobster, *Palinurus eleuthes*, a species monitored by MPA-Agde teams
© Emmanuelle Rivas/French Biodiversity Agency</figcaption></figure>

<figure><img src="image_74.png" /><figcaption>3 red sea squirts, *Halocynthia papillosa*, coralligenous bio-constructor
© Emmanuelle Rivas/French Biodiversity Agency</figcaption></figure>

## Management criteria

### Compliance with regulations and resources

Following the introduction of the fishing area, the town of Agde's marine environment department increased its human, technical and budgetary resources to manage the fishing area as effectively and sustainably as possible. The MPA-Agde application has been improved, enabling strong, diversified communication. A "blue patrol" (marine environmental patrol) has been set up on a permanent basis. Today, nearly 2/3 of surveillance trips reveal a breach of regulations in the Roc de Brescou Marine Reserve, mainly by motorboats engaged in recreational fishing, either anchored or drifting. This result remained constant over the four years observed.

The artificial reef project has achieved its initial objectives of providing a new artificial diving site. The technological work was also coupled with the technical feasibility of the dives through working group discussions with local diving clubs. The diving clubs also signed a charter for the use of the 3D reef to ensure sustainable management of the structure and the village.

Diving centre visitor numbers were limited in the first year, due to the low level of colonisation of the village by marine flora and fauna. After two years in operation, the feedback from divers was very positive, and they identified interesting fauna typical of the Agde area, with the presence of emblematic species such as conger eels, forkbeards, scorpion fish, lobster, black-headed sars and more. Today, all the professional diving centres that visit the coralligenous beds offer diving on this site once or twice a week instead of the coralligenous site.

Scientific monitoring of the artificial reefs is underway, but no monitoring report has yet been published. The artificial structures are currently free of any physical damage, and have survived two winter periods without any displacement or sinking into the substrate.
Critical analysis

Definition of ecological restoration

<table><thead><tr><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Coralligenous bed degradation since 2011.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>The project targeted corall indigenous reefs in their entirety (biotic, abiotic and functional).</td></tr><tr><td>Recovery objective</td><td></td><td>The overall corall indigenous restoration project aimed to re-establish the general state of this ecosystem by protecting 46% of the Adge corall indigenous beds using a fishing area and relocating part of the diving activity to a sandy area with artificial structures.</td></tr><tr><td>Long-term integrity</td><td></td><td>46% of the MPA's corall indigenous beds were protected (via fishing area coupled with diving, dredging and anchoring bans). A Natura 2000 Charter was signed with local diving clubs to limit anchoring on the corall indigenous beds and prohibit it on the artificial village.</td></tr><tr><td>Initial state</td><td></td><td>A corall indigenous bed monitoring programme was launched in 2011. It provided an initial overview of this habitat. A partial initial assessment (granulometry) of the sandy zone hosting the artificial reefs took place prior to their immersion.</td></tr><tr><td>Reference state</td><td></td><td>There was no pre-human activity reference state for the corall indigenous bed. The corall indigenous sites in the area served as a reference for the evolution of the corall indigenous beds in the absence of impact.</td></tr><tr><td>Identified pressures</td><td></td><td>On the corall indigenous bed, the main pressures identified were: diving, recreational fishing (including anchoring in both cases) and, to a lesser extent, professional fishing.</td></tr><tr><td>Intentional process</td><td></td><td>The professional fishermen and the town of Adge decided to initiate this project after noting the degradation of the corall indigenous bed since 2011.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>This project was part of a continuum of actions initiated by the Côte Agathoise MPA to protect the corall indigenous bed while preserving an economic activity. One of these actions was the creation of a fishing area to increase fish stocks and conserve almost half the surface area of the Adge's corall indigenous beds. This area led to the closure of dive sites, increasing pressure on the remaining corall indigenous sites. Following an analysis of the issues at stake (environmental, economic), it was decided to create an artificial area dedicated to diving to alleviate the pressure exerted by recreational diving on the remaining dive sites. The site was chosen in consultation with recreational diving organisations. These structures were to be located at the same bathymetry as the corall indigenous sites (around 20 m), close to the Roc de Brescou. In addition, there was an administrative requirement for the immersion to take place within an existing artificial reef concession.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>The introduction of the area effectively eliminated pressure on almost 50% of the corall indigenous beds. The impact of diving was to be limited by moving to an artificial site and working with the centres to restrict anchoring on the corall indigenous beds and prohibit it on the artificial village (N2000 charter). Nevertheless, the installation of artificial reefs will generate pressure on sandy bottoms, which has yet to be characterised.</td></tr><tr><td>Monitoring</td><td></td><td>The socio-ecosystem components were monitored. The reefs were monitored using BACI-type protocols for corall indigenous beds and the reef village. Based on the strategy document for artificial reef implementation, it will endeavour to monitor the representative components of the two sites (corall indigenous and sandy zones).</td></tr></tbody></table>

This project can contribute to a strategy of natural restoration of corall indigenous reefs and partially meets the definition used in this note.

This action was part of an overall strategy to restore the corall indigenous beds of the Roc de Brescou. The displacement effect of diving pressure and ship anchoring following the creation of the fishing area has led to an accumulation of diving pressure on a limited number of dive sites. After analysis of the environmental issues and consultation with all stakeholders in the area, it was decided to build an artificial reef for recreational diving on a low-risk sedimentary habitat.

Nevertheless, the sandy bottoms on which artificial reefs have been deposited will see their biotic, abiotic and functional components change, giving rise to a new pressure that remains to be characterised.
# Restoration of Gorgonian communities impacted by lost fishing gear

## Project implementation period 2022 - 2023

<figure><img src="image_75.png" /></figure>

12.

## FEEDBACK SHEET

## PROJECT IDENTITY

### TARGET GHT

Sponge, coral beds and coralligenous beds

### ECOLOGICAL ISSUE IDENTIFIED

Gorgonians

### RESTORATION STRATEGY

Contributes to a reconstructive restoration strategy

### COSTS

The total project cost of 41,200 excl. VAT was as follows:

* Development of a gorgonian replanting protocol: 22,000 excl. VAT

* Monitoring of replanted gorgonians and biodiversity: 15,200 excl. VAT

* Capitalising on results: 1,500 excl. VAT

* Communication with users and other local stakeholders: 1,500 excl. VAT

### CONTACT

PALANA ENVIRONNEMENT

/Pablo Liger

pablo.liger@gmail.com

Parc Marin de la Côte Bleue

/Benjamin Cadville

cadville.benjamin@parcmarincotebleue.fr

### LOCATION

Within the Parc Marin de la Côte Bleue, ZSC FR9301999: "Côte bleue marine" in Bouches du Rhône

<figure><img src="image_76.png" /></figure>

## Background and context of the approach

The Palana Environnement association has been running the Net Sea project since 2016; the project aims to identify lost fishing gear and nets, assess their impacts and, if necessary, remove them. This project is being carried out in collaboration with marine protected area managers, professional fishermen, police authorities and recreational divers. One of the impacts of lost fishing gear is the degradation of coralligenous populations, and more specifically of upright species such as gorgonians. When a net removal operation reveals torn gorgonian colonies, specific replanting and monitoring dives will be carried out to help restore the environment and evaluate the success of the operations over time.

The project took place in the ZSC FR9301999 "Côte bleue marine", managed by the Syndicat Mixte Parc Marin de la Côte Bleue (PMCB), in sectors with coralligenous populations impacted by lost nets or repeated anchoring by ships. This habitat is found throughout the site, both inshore at shallow depths and offshore at depths down to -55 to -60 metres, and exceptionally down to -70 meters. The habitat occupies 238.5 ha, or 1.3% of the site's surface area. The coralligenous beds of the Côte Bleue have a variety of micro-habitats that support a wide range of fauna.

Nearly 700 species of invertebrates and around 40 species of fish have been inventoried in the Coralligenous beds at the western edge of the Côte Bleue Marine Natura 2000 site and in the Gulf of Fos.

The aim of this project was to propose the development of a protocol for replanting gorgonians impacted by lost fishing gear, ship anchors or divers' flippers. This protocol would be easy to apply during routine dives by biologist divers in marine protected areas, for example, but also at any other site heavily impacted by ship anchors or with lost fishing nets that can be removed.

<figure><img src="image_77.png" /><figcaption>Red gorgonian, here bicolorled (Paramuricea clavata)
© Palana environnement</figcaption></figure>

<figure><img src="image_78.png" /><figcaption>Fishing net on a gorgonian population
© Palana environnement</figcaption></figure>
## Nature of the operations

The project consisted of several actions:

1. **Development of a** easily applicable gorgonian replanting protocol: This action was subcontracted to the CREOCEAN consultancy office. In particular, its teams drew on feedback from the TRANSCOR project developed by Septentrion Environnement.

2. **Monitoring of replanted gorgonians and biodiversity:**

Monitoring: Monitoring was carried out in several ways:

* Monitoring of gorgonian survival: T+ 1 month/T+ 3 months/T+ 6 months/T+ 12 months/T+ 15 months/T+ 18 months after transplantation: the rate of gorgonian necrosis will be assessed.

* Biodiversity: T+ 1 month/T+3 months/T+ 6 months/T+ 12 months/T+ 15 months/T+ 18 months after transplantation: species list of mobile individuals as well as their number and size class will be evaluated during the gorgonian survival monitoring dive.

* Successful attachment: successive transplantation dives will ensure that the gorgonian is firmly attached to the resin; the success of the attachment will then be assessed at each follow-up dive (T+ 1 month/T+3 months/T+ 6 months/T+ 12 months/T+ 15 months/T+ 18 months).

A zero state assessment was carried out during transplantation in the vicinity of the transplant area, and temperature sensors (HOBO U22 type) were installed.

3. **Capitalising on results**

4. **Communication with users and other local stakeholders.**

## Report by the project leader

**Monitoring of gorgonian survival:** At the Elevine site (wall and canyon), 35 white (*Eunicella singularis*) and yellow (*Eunicella cavolinii*) gorgonians were transplanted at a depth of 30m. The survival rate after 18 months was around 60%. Two *E. singularis* were transplanted at 20 m (early 2022), with 100% survival in December 2023 (T+22months). Unfortunately, none of the five replanted red gorgonians (*Paramuricea clavata*) were found.

The main reasons for this difference in success could be the sensitivity/fragility of the *P. clavata* species, the size of the individuals, and the orientation of the transplants:

* The white and yellow gorgonians were significantly smaller (average 25.8 cm and 19.2 cm respectively), and set on a flat or gently sloping substrate.

* The red gorgonians were much larger (between 30 and 60 cm depending on the individual), and set on a very sloping or vertical substrate.

**Monitoring of benthic species:** The site was heavily covered with encrusting calcareous red algae, *Peyssonnelia spp.*, indeterminate red algae and "Turf".

**Attachment success:** Several tests were carried out on epoxy glues. All were two-component adhesives (one "glue" component and one "hardener" component). After several tests, the Spanish brand Ivegor (recommended by several partners) was selected. After a few months, the glue began to recolonise (attesting to its non-toxicity for benthic organisms).

**Drawing up of a replanting protocol:** Together with the Créocéan consultancy, Palana developed a gorgonian replanting protocol applicable to three species (white gorgonian *E. singularis*, yellow gorgonian *E. cavolinii* and red gorgonian *P. clavata*). The protocol, final report (42 pages) and detailed Retex sheet (5 pages) are available on request.

Several recommendations were made, including:

* the transplantation site should be chosen according to the natural presence of the species, close to the gorgonians found removed,

* the preferred depth was around 30 m,

* the glue should be prepared on the boat, then stored in a transportable bag,

* the individuals selected for the transplantation must not show significant necrosis. Care must be taken to maintain the flaring at the base of the plant,

* the colonies should be transplanted away from turbulent environmental conditions.

The project encountered several difficulties:

* changing weather conditions, leading to the cancellation of several trips,

* the installation of four temperature sensors was rudimentary, even to the point of losing them (a site much frequented by recreational divers),

* the processing of data from several different sensors,

* the lack of response from certain university partners made it impossible to answer the question of artificial genetic mixing due to the transplantation.

<figure><img src="image_79.png" /><figcaption>Newly transplanted colony
© Palana environnement</figcaption></figure>
Critical analysis

Definition of ecological restoration

<table><thead><tr><th>Criteria</th><th>Assessment</th><th>Comments</th></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Degradation of gorgonian colonies by lost fishing gear, non-permanent anchors and recreational diving.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>Not all components were targeted in this project; only three species of the biotic component were targeted.</td></tr><tr><td>Recovery objective</td><td></td><td>The coralligenous habitat as a whole was not targeted in this project, just some of the engineer species in this habitat, which can be home to up to 1,800 species in the Mediterranean.</td></tr><tr><td>Long-term integrity</td><td></td><td>This experimental project helped - but was not enough on its own - to preserve the ecosystem's integrity over the long term without further restoration and management measures.</td></tr><tr><td>Initial state</td><td></td><td>An initial assessment was carried out during the project. It consisted of a description of the site (morphological and bathymetric study, a census of particular structures), a study of the specific diversity, and a demographic study of the trained species.</td></tr><tr><td>Reference state</td><td></td><td>No reference state was targeted during this experimental project.</td></tr><tr><td>Identified pressures</td><td></td><td>The main pressures identified were the mechanical action of lost fishing gear, non-permanent anchoring and recreational diving.</td></tr><tr><td>Intentional process</td><td></td><td>Multiple dives took place within the park's perimeter during the operations to retrieve lost fishing gear, in partnership with the Parc Marin de la Côte Bleue. During these dives, numerous colonies of gorgonian sea fans were found torn off in fishing gear or deposited on the seabed. It was with this in mind that the Palana Environnement association and the Marine Park decided to launch this project.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>The strategy was chosen jointly by the Palana association and the Parc Marin de la Côte Bleue to test a protocol for transplanting gorgonians torn out by fishing nets.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>Although parallel operations aimed to remove abandoned gear from the seabed, pressure on the site was not fully under control.</td></tr><tr><td>Monitoring</td><td></td><td>Monitoring was carried out during the project period (T+18 months) and will continue over the long term by the Palana association, in consultation with the Parc.</td></tr></tbody></table>

This experimental project aimed to transplant colonies of gorgonians torn up by fishing nets, with a view to their recovery. Although it can contribute to a reconstructive restoration strategy, it does not fully correspond to the definition of restoration used in the note. This action concerned three species and did not target a reference ecosystem or all ecosystem components. Nevertheless, this project will have made it possible to refine an existing protocol so it can be deployed at sites impacted by this pressure, and to raise user awareness of the richness of the coralligenous habitat.
SOFT SEDIMENTS
(NOT DEEPER THAN
1000 METRES OF DEPTH)

Coarse loose substrate and Posidonia (Posidonia oceanica) meadow
© Antonin Guillbert/French Biodiversity Agency
# Limiting of Smooth cordgrass
(Sporobolus Alterniflorus) in the Roadstead of Brest

## Project implementation period 2021 - 2022

<figure><img src="image_80.png" /></figure>

13.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Soft sediments
(above 1,000 m)

### ECOLOGICAL ISSUE IDENTIFIED

* The last *Limonium humile* stations

* Salt meadows of Community interest,
in particular those with floristic
diversity

* Areas of high importance for the feeding and resting of wintering avifauna (particularly mudflats).

* Dwarf eelgrass (*Zostera noltei*) meadows

### RESTORATION STRATEGY

Contributes to an assisted restoration
strategy

### COSTS

The total cost of the project was
€94,024.26 incl. VAT

### CONTACT

Parc Naturel Régional d'Armorique
/Anna Le Joncour
Anna.le-joncour@pnr-armorique.fr

### LOCATION

Within the Parc Naturel Régional d'Armorique (PNRA), ZSC FR9301999: "Rade de Brest, estuaire de l'Aulne" in Finistère

<figure><img src="image_81.png" /></figure>

## Background and context of the approach

In Brittany, the Spartina genus is represented by a single native species, small cordgrass (*Spartina maritima*). This has been strongly challenged by the appearance of three other species in the same genus: smooth cordgrass (*Spartina alterniflorus*), Townsend's cordgrass (*Spartina townsendii*) and common cordgrass (*Spartina anglica*), the latter two being the result of hybridisation between *Spartina maritima* and *Sporobolus alterniflorus*. Only *Sporobolus alterniflorus* is present in the Roadstead of Brest. This hardy poaceae of American origin first appeared in Europe in 1836 in the English port of Southampton (Tournay, 1996). At the end of the 19th century, it settled in France, where it is currently only present in a few stations in Aquitaine and Vendée, in the Hendaye region and in the Roadstead of Brest. Its introduction into the Roadstead of Brest probably dates back to the end of the First World War, accidentally transported by American ships (Dizerbo, oral communication in Bonnot-Courtois et al., 1989 cited in Sparfel et al., 2005).

Today, *Sporobolus alterniflorus* has invaded all the coves in the Roadstead of Brest. An analysis of the vegetation maps of the Roadstead of Brest and the Elorn River carried out in 2004 and 2005 as part of the Natura 2000 inventories made it possible to assess the proportions of Spartina in relation to other plant groups in coastal marshes (Bougault et al., 2004 - 2005). The community of Spartina with alternate flowers represented 60% (Roadstead of Brest) of the surface area occupied by vegetation characteristic of the mudflat and salt marsh. In 2014, 60.26% of the salt meadows in the Roadstead of Brest were invaded (Source: Maxime Hourdé, PNRA, 2014).

Since 2011, several studies and projects to test different control techniques have been carried out by the PNRA in partnership with scientists (LEMAR laboratory at the Institut Universitaire Européen de la Mer) and other managers (Association Bretagne Vivante, Conservatoire botanique nationale de Brest, association Al'terre breizh, Association de chasse sur le Domaine public maritime du Finistère, association Don Bosco, Brest métropole). These actions followed tests carried out by the Conservatoire Botanique National de Brest and mapping work by IUEM scientists. In 2015, a prioritisation strategy was put in place based on various environmental, technical and human criteria, resulting in the definition of around 20 priority intervention sites. Complementary full-scale projects confirmed the choice of certain effective techniques. A technical guide was also produced based on these experiences.

In 2021, the Parc naturel régional d'Armorique applied for funding under the French government's stimulus plan to carry out new projects to combat smooth cordgrass in the Roadstead of Brest over the period 2021 - 2022.
## Nature of the operations

This project required the implementation of a smooth cordgrass control strategy, based on over ten years of local experimentation.

### 1. Analysis of environmental characteristics:

The nature of the substrate appeared to be a limiting factor. Vaso-gravelly and gravelly-cobble substrates slow down colonisation by the species and/or limit its establishment (Queré, 2010) (Sparfel et al., 2005). In the field, the species seems to cope with variable salinities between 20 and 35 %. Observations made in situ or experimentally in greenhouses have shown that in environments with low salinity, or occasionally desalinated with freshwater, production and biomass tend to increase sharply (Broome et al., 1986). Lastly, the factor that seems to limit the extension of spartinae on low mudflats is immersion time. Below a minimum altitude of 0.9 m observed in the Roadstead of Brest, the immersion time was too long for the species to survive, as observed at the Anse du Moulin Neuf site (Plougastel-Daoulas) in 2005 (Sparfel et al., 2005). At this 0.9 m level, the immersion time was 27%. This corresponds roughly to the low-water coast at coefficient 50 (pers. com. Nathalie Poupart, IUEM).

### 2. Choice of control techniques:

* Topping was preferred on gravelly substrates, where the root and rhizomatous system was shallow. When the patch was small, or the substrate was too soft or the environment too fragile, the spartina was removed by hand using a spading fork and then a caterpillar wheelbarrow. The mini tractor was used for larger patches. The spartina was removed outside the limit of the highest tides, in the vegetation bordering the site, or along existing embankments.

* On muddy substrates, tarpaulins were preferred. Generally speaking, only surfaces under 2,000 m² were treated. Trenches were dug by hand around the spartina patches, then several opaque black tarpaulins were installed and stretched taut. The edges of the tarpaulin were pushed into the trenches and covered by the silt. Fenders (approx. 1 per 2 m²) were then fitted to secure the tarpaulin to the ground.

* Trench isolation was used when surface areas were too large. A trench was dug along or around a patch of spartina to isolate it and prevent it from spreading through its rhizomes.

### 3. Prioritisation of issues:

The intervention sectors were prioritised according to the issues at stake on the site, and the technical, financial and human feasibility. By cross-referencing these layers of information with the updated spartina mapping, areas of potentially negative interaction appeared between the spartina and each issue (ecological, landscape and use).

### 4. Site scheduling:

Following the different analyses, some 30 sites were selected, spread over 13 communes. This corresponded to controlling 1.5 ha of cordgrass, including 6,200 m² by tarping, 2,300 m² by spraying and 6,400 m² by isolation.

### 5. Awarding of a contract to carry out the work

### 6. Monitoring the effectiveness of actions

Parc d'Armorique teams regularly monitor ongoing projects to ensure that the tarpaulins are in good condition and check for spartina regrowth. Particular attention is paid in winter, when winter storms can damage the tarpaulins. The tarpaulins are removed after three years, or when they have deteriorated too much to play their role properly.

<figure><img src="image_82.png" /></figure>

<figure><img src="image_83.png" /></figure>

<figure><img src="image_84.png" /></figure>
## Report by the project leader

In all, 6,003 m² of Spartina were removed by tarpaulin covering and 1,001 m² by topping. This represents a total of 7,004 m². In addition, 409 linear meters of trenches were used to isolate 4,477 m² of Spartina.

Some worksites were cancelled and could not be carried out for a number of technical feasibility reasons, such as inaccessibility of the site or the substrate being too soft to allow contractors to reach the site. They were therefore abandoned.

Staffing problems at one of the contractors also caused delays. The schedule forced the project coordination teams to cancel certain worksites, such as those in the commune of Guipavas, outside the Natura 2000 site of the Roadstead of Brest.

The project also enabled the PNRA to refine the techniques it has developed for controlling spartina:

### Topping:

This feedback confirms the feasibility of mechanical topping on small surfaces (less than 50 m²), but for larger surfaces it is preferable to use the tarpaulin technique.

The main limitation of the topping process is the size of the patch and the amount of waste to be removed. For small patches of less than 20 m², it is easy to carry out topping by leaving the waste in place, provided there is an easily accessible spot nearby, above the high tide line. Beyond this surface area, it is difficult to leave waste on site. The nature of the substrate also limits this technique: the terrain must be firm and access to the site easy to facilitate the arrival of machinery and the

removal of waste.

### Tarpaulins on gravelly substrate:

Laying tarpaulin proved complicated on Spartina surfaces on gravelly substrate, as the tarpaulin did not adhere to the substrate. These sites had to be revisited several times as the tarpaulins were not holding up well. The technique of tarping over gravelly substrate was finally refined and approved, on condition that the trenches were made mechanically beforehand.

The experience with these projects also confirmed that tarpaulins are a useful technique for areas of less than 2,000 m². Beyond that, trench isolation is required.

### Post-work monitoring:

It is important to carry out regular monitoring of sites where Spartina has been eradicated. Where topping has been carried out, small clumps of Spartina may grow back where fragments of rhizomes may have remained. It is best to pull them out as soon as they re-grow to prevent them spreading. It is also essential to monitor the tarpaulins, which remain in place for three years. Regular monitoring will make it possible to put back pieces of tarpaulin that may move with the tides and currents, particularly during the winter period. A network of volunteers could be set up to monitor and intervene if necessary.

Following this project, a decision chart was drawn up to replicate it on other Natura 2000 sites:

<figure><img src="image_85.png" /></figure>
Critical analysis

Definition of ecological restoration

<table><thead><tr><td>Criteria</td><td>Assessment</td><td>Comments</td></tr></thead><tbody><tr><td>Degraded ecosystem</td><td></td><td>Acknowledgement of the spread of the invasive exotic species to the detriment of natural habitats in the Roadstead.</td></tr><tr><td>All the targeted ecosystem components</td><td></td><td>This comprehensive project aimed to recover the main components of the ecosystem.</td></tr><tr><td>Recovery objective</td><td></td><td>The aim was to recover a set of habitats in their entirety: biotic, functional and abiotic. This operation also focused on the conservation of the <i>Limonium humile</i> species, which on a national scale is only found in the Roadstead of Brest.</td></tr><tr><td>Long-term integrity</td><td></td><td>This experimental project helped but was not enough on its own to preserve the ecosystem's integrity over the long term without further restoration and management measures. This invasive species has become virtually naturalised, making complete eradication on a sectoral scale impossible.</td></tr><tr><td>Initial state</td><td></td><td>The initial assessment was based on an update of the 2014 Spartina mapping, but did not involve measuring all the components representative of the targeted habitats.</td></tr><tr><td>Reference state</td><td></td><td>The reference state targeted in the overall project was to return to a state prior to the 1950s, the probable date of the arrival of Spartina in the Roadstead of Brest. This area was considered unreachable due to the excessive surface area colonised by Spartina.</td></tr><tr><td>Identified pressures</td><td></td><td>One of the main pressures on the habitats targeted by the project is the expansion of smooth cordgrass and the disturbance of wintering birds.</td></tr><tr><td>Intentional process</td><td></td><td>Following the massive expansion of cordgrass in the Roadstead of Brest since the 1950s and the degradation of natural habitats, the PNRA has launched a strategy to combat this invasive species.</td></tr><tr><td>Choice of intervention strategy</td><td></td><td>The strategy was drawn up with the help of scientists and marine environment stakeholders. After more than ten experiments, an assisted restoration strategy was selected for targeted sites.</td></tr><tr><td>Pressure reduction/elimination</td><td></td><td>Spartina was the main remaining pressure threatening the viability of these habitats. The wintering birds occupying these habitats have to contend with disturbance from walkers. To help reduce this pressure, the PNRA introduced measures such as bird observatories and marked hiking trails. Chemical pressure was not assessed.</td></tr><tr><td>Monitoring</td><td></td><td>Only part of the biotic component was monitored: surface study (monitoring regrowth) of the Spartina, monitoring of <i>Limonium humile</i> and wintering bird populations.</td></tr></tbody></table>

This project aimed to combat the invasive species *Sporobolus alterniflorus* in the Roadstead of Brest and may contribute to an assisted restoration strategy for its habitats. The eradication of the species on a large scale was impossible due to its widespread presence. Only a few sites can still be restored.

This series of actions was part of a continuum of projects to combat cordgrass that have been carried out by the PNRA for over ten years. A technical guide sets out all the techniques tested, along with the methods for choosing and using each selected technique. It is available from the PNRA on request or can be downloaded from the following link: https://www.calameo.com/ofbiodiversity/books/00350294843a08ab9cda6

A Master's internship is currently underway to understand the spatial evolution and dynamics of cordgrass in the Roadstead of Brest.
# Restoration of mudflats in the Bay of Aiguillon

## Project implementation period 2019 - 2021

<figure><img src="image_86.png" /></figure>

14.

FEEDBACK
SHEET

## PROJECT IDENTITY

### TARGET GHT

Soft sediments
(above 1,000 m)

### ECOLOGICAL ISSUE IDENTIFIED

Mudflats

### RESTORATION STRATEGY

Contributes to a natural and assisted
restoration strategy

### COSTS

One of the LIFE Baie de l'Aiguillon actions, which involved the restoration of mudflats by removing former shellfish farms colonised by Japanese oysters, was as follows (€ inc. VAT):

* Regulatory instruction: €40,000

* Faunal inventory, particle size analysis and organic matter determination: €24,000

* Scrap metal recycling: €620 per ton

* Deposit withdrawal: €10.80-1.40/m³ or €5,200/ha

* Topographical survey: €18,000 for 7,000 hectares

* Recycling channel test: €1,080/m³

* REMI monitoring laboratory analysis: Between €25 and €30 per collection point

### CONTACT

Réserve naturelle nationale
de la baie de l'Aiguillon

/Jean-Pierre Gueret
jean-pierre.gueret@lpo.fr

/Louise Froud
louise.froud@lpo.fr

FBA/ Régis Gallais
regis.gallais@ofb.gouv.fr

### LOCATION

Within the Réserve naturelle nationale de la baie de l'Aiguillon, ZSC FR5200659 "Marais Poitevin" and ZSC "FR5400446", in Vendée and Charente-Maritime

<figure><img src="image_87.png" /></figure>

## Background and context of the approach

The Réserve Naturelle Nationale de la baie de l'Aiguillon is home to mussel and oyster farms, which have gradually slid downstream as a result of the gradual natural silting-up of the bay and the *Mytilicola intestinalis* crisis. The shellfish farming concessions abandoned in the 1960s have not been restored by their private owners and are now being used to support the development of wild beds of Japanese oysters *Magallana gigas*.

These oyster shell deposits have the following impacts:

* loss of natural mudflat habitat;

* sediment trap promoting accretion;

* local changes in current dynamics;

* competition with farmed shellfish for food resources.

To this end, LIFE Baie de l'Aiguillon implemented a mudflat restoration project involving the removal of these oyster beds.

Three intervention zones were identified, two in Vendée and one in Charente-Maritime, covering a total area of 190 hectares. The aim was to restore a minimum of 100 hectares of mudflat using two amphibious machines capable of moving over mud and through water. The interventions that took place on low tides with a coefficient of 60 or higher involved removing the supports (mainly oyster tables) and crushing the oyster shells on site.

Three winter work phases took place between September 2019 and November 2021, involving 158 tides and the restoration of approximately 118 hectares of mudflat, corresponding to approximately 42,000 m³.

<figure><img src="image_88.png" /><figcaption>Removal of oyster shell deposits
© LIFE Baie de l'Aiguillon</figcaption></figure>