Located on the Caribbean coast of Martinique, the Bay of Fort-de-France is a strategic and dynamic area, characterized by dense coastal urbanization.

It is home to around 40% of Martinique’s population, as well as major commercial and transport infrastructures, particularly a port and an international airport, thus playing a central role in the island’s economic, social, and cultural life.

In addition to significant urban development, the Bay of Fort-de-France also includes large agricultural areas, notably dedicated to sugarcane cultivation, as well as vast natural spaces.

However, due to its low elevation, part of this territory is now exposed to marine flooding, and the agricultural lands are experiencing soil salinization, threatening the existing agricultural model.

The Fort-de-France mangrove, also known as the Génipa mangrove—the largest mangrove in Martinique—is a key element of the area and plays a crucial role in coastal protection and biodiversity preservation. It is home to several plant and animal species endemic to the island, including various types of mangroves and mahogany trees.

The southern part of the bay was assigned to the Coastal Protection Agency (Conservatoire du Littoral) in 2015, followed by the northern part in 2017.

Fauna and flora

It is possible to observe mangrove species such as Rhizophora mangle (red mangrove), Avicennia germinans (black mangrove), Laguncularia racemosa (white mangrove), and Conocarpus erectus (buttonwood or grey mangrove). Protected plant species include: Oncidium ceboletta (orchids), Ammania coccinea (scarlet ammania), and Zygia latifolia (river acacia). Two CITES-listed species (Convention on International Trade in Endangered Species of Wild Fauna and Flora): Swietenia macrophylla (Honduran mahogany) and Swietenia mahagoni (West Indian mahogany), as well as 153 plant species from the back-mangrove zone.

Local partners:

The Lancieux Bay is an area gradually reclaimed from the sea by humans (polder). Over the centuries, the successive construction of dikes (such as the Dike of the Monks, the Roche Dike, or the Beaussais Dike) and irrigation canals has made it possible to develop agriculture.

The landscape has thus been shaped according to human needs, alternating between salt meadows, vegetable farming, bocage pastures, apple orchards, cereal crops, and wet meadows.

The Conservatoire du littoral’s land ownership of the polder has made it possible to initiate a transition of agricultural land. By establishing permanent grasslands without inputs, the aim is to improve water quality and reduce economic pressures in a sensitive area.

The Lancieux Bay has retained a wild character, with a great diversity of natural landscapes, while still being inhabited and used by humans.

Between the 13th and 16th centuries, the Benedictine monks of the Abbey of Saint-Jacut built a dike, now known as the “Dike of the Monks.” It enabled the draining of the coastal marshes for agricultural use. Later, the Roche Dike (18th century) marked the extension of the polder to its current boundaries. The Beaussais marshes (Ploubalay polder), separated from the Lancieux polder by a watercourse, were drained through the construction of a dike in the early 19th century. These two adjacent polders form a coherent unit within the Lancieux Bay.

The Dike of the Monks is the oldest heritage feature of the site and represents a valuable testimony to the development of the land-sea interface over past centuries.

Project actions and outcomes

Climate change and rising sea levels are causing changes along the coastline. During high spring tides, the sea now reaches the tops of the dikes and sometimes overflows them during storms.

Since 2015, new approaches to land management have been explored in order to anticipate the effects of rising sea levels. A strategy of planned dike retreat over time is gradually giving back to the sea what humans had reclaimed.

Accepting the maritime nature of the bay means shifting the perspective of users—allowing the sea to reclaim some space and creating new areas for walking and recreation.

Allowing saltwater to enter the low-lying inland marshes in a controlled way provides a new area for sea expansion. This helps absorb part of the sea’s energy during storms and reduces the cost of building and maintaining protective infrastructure. The bay offers favorable conditions for this flexible approach to coastal management.

Several reconnection scenarios have therefore been evaluated for the Lancieux polder:

• Dike removal
• Creation of breaches
• Installation of water control structures (sluices)
• Natural (uncontrolled) tidal flooding

Thus, in the municipality of Lancieux, this transitional area makes it possible to envision a layered protection system based on:

• The restored historic Dike of the Monks, repurposed as a walking path;
• A new, limited-length dike providing protection for people and property between the Dike of the Monks and the urbanized areas;
• The controlled intrusion of saltwater into the area returned to the sea, creating a new salt meadow marsh that helps dissipate wave energy.

The aim here is to balance heritage, environmental concerns, and the use of natural spaces through a strategy of gradually supporting the landward retreat of the coastline.

Chronology

• July 27, 2011: Resolution by the Lancieux municipal council proposing a system of successive defense layers: relying on the Dike of the Monks and, if necessary, implementing a third dike to protect the campsite and nearby homes.
• 2015: Hazard study – Assessment of the dike’s condition and maintenance recommendations. Definition of the vulnerable area.
• 2016: Meetings with mayors and intermunicipal officials – concerns about how residents might receive the project. Desire to highlight the benefits of the project for local residents as well as for tourism. Growing awareness of the emerging challenges related to climate change, which the Community of Municipalities will have to address within the GEMAPI framework (flood risk and aquatic environment management).
• November 4, 2016: Presentation of the results of geomorphological and landscape university studies to elected officials of the Côte d’Emeraude. Questions raised about project funding and the interest in a reconnection initiative rather than simply allowing nature to take its course. Desire to include cost estimates and assess technical and legal feasibility for each scenario.
• November 15, 2016: Exchange day between elected officials from Val de Saire (Licco site, Normandy) and those from the Bay of Lancieux on adapting coastal territories to climate change.
• 2017: Studies on “Ecosystem services of a Slikke-Schorre complex” and “Biogeomorphology and evaluation of the storm attenuation service of the Lancieux Bay salt marsh” (EPHE study).
• November 21, 2016: Discussions with the municipality of Lancieux on establishing a DUP (Public Utility Declaration) to secure land control—key to advancing the Adapto project.
• November 6, 2017: COPIL (steering committee) meeting for the implementation of GEMAPI.
• July 11, 2018: Site management committee for Tertre Corlieu and Beaussais Marshes.
• August 8, 2018: Meeting with the mayor of Lancieux about land acquisitions and water management in the Lancieux marsh.
• November 2018: Acquisition of parcel AH 238.

Over more than 420 hectares protected by the Conservatoire du littoral, the Lido de l’Or (Petit and Grand Travers) consists of natural environments of high ecological value such as dune ridges, salt marshes, and forested areas that require particular attention for biodiversity conservation. It is notably part of the European Natura 2000 network of protected sites.

Located between the urban areas of La Grande Motte and Carnon, this area is particularly fragile, subjected to strong pressures from both natural and human origins. While it experiences significant erosion effects on the Petit Travers, year-round tourist activity greatly contributes to the degradation of the coastal strip.

After extensive consultation, Petit Travers was the subject of an ecological restoration project in 2014. Between 2017 and 2022, the Life Adapto project helped to consolidate and share the experience of restoring Petit Travers and to develop a forward-looking, cross-sectoral vision for the Lido over the medium and long term.

Today, the ambition is to expand the project to cover the entire Lido, including Grand Travers. This project aims to better manage the multiple uses and the very high visitor numbers over the long term while improving visitor facilities, maintaining or even developing agricultural activity, implementing innovative forest plantation management solutions with the National Forestry Office (ONF), connecting the site to the river network, and restoring and opening to the public an 18th-century signal tower listed as a Historic Monument. In this context, the Life Adapto+ project is intended to provide decision-support tools to feed the project and anticipate updates to the site’s management documents through the lens of climate change adaptation.

Fauna and flora

It is possible to observe numerous bird species such as the Crested Lark, Blue Tit, Willow Warbler, Nightingale, Blackcap, and Green Woodpecker. During migrations, migratory passerines are also seen resting during stopovers. The flora is also extremely diverse, with over 150 species, including 21 considered to be of heritage value.

The Loire Estuary site has a unique dimension: spanning over 5,500 hectares, it is characterized by a rich network of wetlands, part of which is used for agriculture—mainly livestock farming. Within this site, four areas are or will be part of the Adapto+ Loire Estuary initiative.

Corsept, the westernmost area on the south bank of the estuary between the communes of Paimboeuf and Saint-Brévin, underwent a series of actions carried out between 2022 and 2024 as part of the Adapto Estuary Corsept project. Studying the expected changes at the land-sea interface, this approach highlighted adaptation pathways to rising sea levels for these areas, which include hay meadows, pathways, and nearby buildings.

Lavau-sur-Loire is one of the three new areas integrated into the LIFE Adapto+ project. This site, covering around 2,700 hectares and encompassing the former islands of North Loire, is located 19 km from Saint-Nazaire and 33 km from Nantes. To the east are Massereau-Migron, including the former islands of South Loire, and the Percée de Buzay, together covering an additional 2,200 hectares. These sites are partly designated within the European Natura 2000 network. These three new sites, where changes are already noticeable (vegetation, landscapes, and evolving uses), will be subject to further study within the LIFE Adapto+ framework.

Fauna and flora

It is possible to observe many species across these four sites, such as the European otter, Alpine longhorn beetle, stag beetle, great crested newt, sea and river lamprey, twaite shad, European eel, several species of bats including the barbastelle, lesser horseshoe bat, and brown long-eared bat, as well as numerous bird species: black-winged stilt, pied avocet, golden plover, Eurasian spoonbill, black-tailed godwit, northern shoveler, marsh snipe, common shelduck, bluethroat, marsh harrier, aquatic warbler, and reed warbler…

Owned by the State since the late 19th century and currently managed by the National Forestry Office (ONF), the Luzéronde site is located in the northwest of the island of Noirmoutier and is part of the European Natura 2000 network of sites.

This site is a textbook example of a coastal dune in contact with a rock revetment. It consists of a dune ridge that protects extensive agricultural and aquaculture areas, as well as several urbanized zones located to the east (mostly private land), from flooding. This natural barrier currently varies in width from 80 meters in the northern part of the site to 20 meters in the south—the area adjacent to the Devin dike. In the event of a breach during major weather events, the island of Noirmoutier would be severely impacted.

The ONF, as owner and manager of the dune area, and the Community of Communes of the Island of Noirmoutier (CCIN), within the framework of GEMAPI, have been working together for several years to reduce risk on the southern part of the dune ridge.

The Life Adapto+ project aims to strengthen this previously initiated approach by improving the dune’s resilience through actions that enhance sediment exchanges at the dune foot and support managed retreat of the dune ridge (accompanied translation). This project relies on the expertise of partner organizations (Cdl, BRGM, CEREMA, Observatory of the Island of Noirmoutier, ONF) as well as the shared commitment of local stakeholders (CCIN, municipalities, etc.) to promote nature-based solutions to address the effects of climate change.

The findings could lead to the creation of new management tools with national and European relevance for similar configurations.

Fauna and flora

It is possible to observe Ammophila arenaria, Cakile maritima, Euphorbia paralias, Calystegia soldanella, the coastal Omphalodes, Eryngium maritimum, as well as the Western spadefoot toad (Pelobates cultripes), a reptile species endangered in mainland France.

The morphology of the Orne estuary, from Caen to the sea, was significantly altered following the construction of the canal in 1857. After passing through Caen, the Orne River splits into two straight lines that structure the surrounding landscape. These two watercourses—the Orne and the canal—flow between two agricultural and urban plateaus, shaping a variety of evolving landscapes. The western corridor, guided by the canal, conveys an industrial and port-related character. To the east, the river changes with the tides, feeding a rich natural heritage: the Bay of the Orne.

The river’s embankment led to the disappearance of salt marshes (schorre) over much of the site. The banks of the Orne were reclaimed (polderized) all the way to its mouth. The Cagny marsh dike was built in the 18th century, transforming the former meander and its salt meadows into grazed wet grasslands. The François Fields polder is the result of more recent embankment works (1960s) on a tidal flat. As a result, downstream from the Montalivet dam (in Caen), the lateral expansion zone for natural habitats and tidal flooding now remains along only about one-fifth of the river’s length.

In 2011, the Cagny marsh dike failed, causing flooding in low-lying areas. During high spring tides, the sea occasionally overtops the dike, forcing the temporary closure of the cycle path built along its crest. This calls for a reassessment of the dike’s future—and more broadly, of the land behind it.

Today, available data on this site indicate that maintaining these polders in their current state is not the only possible vision for the future of the area. In fact, the return of salt meadow vegetation in the François Fields sector offers clear benefits in terms of economy, biodiversity, and landscape.

On the Cagny marshes, the LiCCo program (Coastal and Climate Change), carried out from 2011 to 2014, provided valuable insight into the evolution of the Orne estuary. A collective reflection was launched with all local stakeholders on what the coastline of tomorrow could look like. Adapting this estuary in the context of climate change and rising sea levels is based on:

• A vision for 2050: the development of a larger, deeper estuarine area to increase climate resilience;
• A trajectory to 2025: implementation of concrete, localized projects to re-establish lateral floodplain connectivity and promote coastal mobility.

The Orne, heavily canalized, lacks sufficient space for flood expansion—raising the issue of opening up the polders and affected marshes.

Project actions and outcomes

At Sallenelles, the approach involves working with local stakeholders to define public access facilities during the re-flooding of the François Fields.

Regarding the Cagny marsh, a process of reflection and project definition needs to be initiated, starting with historical and landscape analyses, followed by the development of prospective scenarios. In a scenario involving sea level rise, erosion, and rising groundwater levels, the current Cagny marsh dike would become obsolete and lose its protective function. Based on this analysis, the Conservatoire du Littoral and the Calvados Departmental Council, which manages the natural areas, are working on an alternative to the existing cycle path.

If the maritime character of the marsh is restored, new walking, cycling, and boating routes would offer visitors new experiences. Starting from the Nature and Estuary House, these paths contribute to maintaining the site’s appeal at the heart of the bay. At the same time, a consultation process should be conducted with Normandie Cabourg Pays d’Auge, the Chamber of Agriculture, Safer, the Conservatoire du Littoral, and local farmers to plan the gradual adaptation of their working tools over the coming years for this scenario.

Preliminary Study for 2050: Download now

Furthermore, addressing climate change requires a broader perspective than just the mouth of the Orne estuary (the intervention area of the Conservatoire du Littoral). Restoring the maritime character of the Orne demands a well-considered strategy at the scale of the entire Orne River—from Caen to the sea. Planning adaptation through different stages up to 2050 involves the participation of various stakeholders:

• The Calvados Department (greenways, sensitive natural areas, etc.), the CPIE
• The City of Caen, the Communauté de commune Caen la Mer, the Communauté de commune Normandie Cabourg Pays d’Auge, and the municipalities located downstream of the estuary (GEMAPI, urban planning documents, urban development of the peninsula…)
• Ports of Normandy (master plan for port development)
• State services (Risk Prevention Plan).