Despite the imminent threats associated with global warming, the demographic impact of environmental disruption has rarely been studied at the local level. In northern Senegal, the construction of a canal designed initially to prevent local flooding has led to severe coastal erosion and the salinization of fishing zones and the soil. Because of these changes, the inhabitants of Gandiol municipality have lost certain traditional sources of income. How have their livelihoods been affected? What is the role of migration in the response to these upheavals? This article describes how the population has adapted to the degradation of its environment.
1In 2003, the city of Saint-Louis in Senegal experienced serious flooding. To manage water levels in the Senegal River, the authorities decided to build a drainage canal on the Langue de Barbarie to divert flood waters towards the Atlantic Ocean. [1] Initially 4 m wide, this man-made breach, commonly known as la Brèche, rapidly and unexpectedly grew southward, reaching a width of 5,200 metres in 2015. [2] This uncontrolled widening of the breach exposed the municipality of Gandiol, 18 km south of the city, to severe coastal erosion. Gandiol comprises 30 villages and nine hamlets (Communauté rurale de Ndiébène-Gandiol, 2010), with a population of 21,182 in 2013 (ANSD, 2013). The local economy is based mainly on market gardening, fishing, and livestock production, alongside activities related to tourism and salt production.
2As the breach widened, two villages were swallowed up by the sea, and others remain under threat (Sy et al., 2015). Its southward expansion is continuing (Durand et al. 2010). While the effects of this encroachment may lessen over time, its environmental and social impacts are immense. As well as destroying habitats, the advancing sea has affected local fishing, market gardening, and livestock production.
3Before the breach was constructed, boats could fish in the Senegal River and the Atlantic Ocean, depending on the season, the weather, and sailing conditions. The breach destroyed mangrove fish breeding grounds and allowed seawater to mix with the fresh water in the river, leading to accelerated decline of fish stocks. Crossing the breach by boat has also become a dangerous endeavour. The fishermen’s canoes frequently capsize, sometimes with loss of life. These destructive changes threaten the livelihoods of local populations that rely on fishing for subsistence.
4Coastal flooding increases soil and groundwater salinity, reducing biodiversity and limiting the diversity and yields of vegetable and fruit crops (Tine, 2020). In the past, a wide range of fruits and vegetables could be grown and harvested all year round. Today, among the vegetables grown in the region, only two species of onions can grow in the saline soil. The decrease in uncontaminated watering points and pastureland has forced livestock breeders to limit their herd sizes, and the cost of maintaining large herds had become prohibitive (Tine, 2020).
5This decline of the primary sector makes it more difficult for local inhabitants to maintain their livelihoods and obtain a steady income, and many households must find new ways of adapting to the changed environment. Migration is one possible response to environmental stress (McLeman and Smit, 2006), notably via remittances (Foresight, 2011) sent back by migrants to improve the living conditions of local populations (Adger et al., 2002). By studying this migration, we hope to gain a clearer understanding of the dynamics and processes at play in this context. For Gandiol, we posit that migration is a strategy of adaptation to environmental degradation.
6Applying the ‘migration for adaptation’ approach, this article proposes a typology of the consequences of migration strategies on the adaptive capacity of households in Gandiol. After introducing this approach and its application to Senegal, it describes the demographic context of the Gandiol municipality via a typology of the data collected during a field study conducted in July and August 2017.
I – Migration as an adaptation to environmental change
7The Intergovernmental Panel on Climate Change defines adaptation as:
This definition evokes the notions of adaptability and survival capacity under new climate conditions that modify original habitats. The strategies deployed, often independent and spontaneous, are a response to climate change, with the aims of reducing vulnerability and increasing resilience (Mertz et al., 2009). In this way, populations incorporate new practices into their social system (Mansanet-Bataller, 2010).
1 – Theoretical considerations
8In the research literature, environmental migration is often seen as an adaptation strategy (McLeman and Smit, 2006; McLeman et al., 2008; Upadhyay and Mohan, 2017). [3] Research in this field looks beyond the immediate causes of migration by examining the multiple factors at play, notably in contexts of environmental change (Sakdapolrak et al., 2016; Baldwin and Fornalé, 2017).
9The ‘migration for adaptation’ approach considers that new opportunities and resources in receiving regions provide a means to diversify livelihoods, promote climate adaptation, and strengthen social resilience among sending and receiving communities and the migrants themselves (Gemenne and Blocher, 2017). Transfers of money, technology, best practices, and networks are considered to contribute to institutional and technical consolidation and innovation in response to environmental change (Barnett and Webber, 2009; Scheffran et al., 2012).
10Migrant remittances provide support to households in three ways (Gemenne and Blocher, 2017): by providing resources to overcome natural disasters; by creating opportunities for income-generating activities and investments; and by financing collective adaptation projects. Migration is thus seen as a response that serves to diversify income sources and reduce dependence on natural resources (Tacoli, 2011).
11Two approaches can be combined under this theoretical framework. The sustainable livelihood approach applied to translocal spaces examines the use of individual and household skills and resources to improve livelihoods within the limits of the opportunities and constraints of the living environment; individuals are considered active agents (Greiner and Sakdapolrak, 2013a, 2013b; Schöfberger, 2017). The second approach, that of the new economics of labour migration, uses the household, not the individual, as the unit of analysis (Piguet, 2018). It has a somewhat optimistic vision of migration, which it sees as a strategy for spreading household risks (Piguet, 2018).
2 – Application to Senegal
12In Senegal, during environmental crises such as natural disasters, migrant remittances are used mainly by households to buy food and basic consumer goods to survive over the short and medium term (Tacoli, 2011; Lo et al., 2014; Lalou and Delaunay, 2015; Tandian, 2015; Wade et al., 2017; Zickgraf, 2018; Sakho et al., 2019). Households also invest in access to basic services such as health or education (Sakho et al., 2019). Consistent with research conducted elsewhere, our initial observations in Senegal suggest that these financial resources represent a form of social insurance for households (Gubert, 2002; Clarke and Wallsten, 2003; Yang and Choi, 2007; Gioli, 2017). These short-term strategies sometimes take precedence over long-term investment in environmental risk reduction, but they serve to reinforce the social prestige of the household (Wade et al., 2017).
13For farmers, money received from migrants can be used to develop forms of land use more suited to the new environmental conditions or, in certain cases, to maintain traditional economic activities (Romankiewicz et al., 2016). Other investments are designed to increase longer-term economic security. For example, migrant remittances may be used to improve housing (Tacoli, 2011), thereby contributing more broadly to the development of sending localities (Tandian, 2015).
14While remittances support adaptation strategies, the scientific literature points up that households and national economies run the risk of becoming dependent on external markets. Schöfberger (2018), who uses the concept of ‘translocal livelihood strategies’, implies that migration between different places may facilitate household adaptation. While emigration enables certain household members to remain in their home village, those left behind may become dependent on remittances if they do not invest in income-generating activities. Household vulnerability may thus be increased in sending areas and transmitted to receiving areas. Couharde and Generoso (2015) observed the macroeconomic consequences of these money transfers on the economic performance of West African countries during environmental shocks of the period 1985–2007. Their results showed that remittances have a significant but ambiguous impact on the economies of countries experiencing climate events. During droughts, they provide support for household adaptation but raise demand for imported farm products and increase the dependence of local economies on external markets. That said, while migrant remittances pose a risk of dependence for households and national economies, they may also partly make up for the lack of resources to implement environmental adaptation policies at the government level.
15Given the small number of case studies, the dispersion of research centres, and the broad range of methods and disciplines involved, the results of the migration-for-adaptation approach are still very fragmented. Research lacks qualitative empirical data on how adaptation capacities are affected by these remittances and by migration. Likewise, little is known about the perceptions of the beneficiary populations themselves (Le De et al., 2013).
16This article aims to flesh out existing empirical knowledge. By proposing a typology of the impact of remittances and of emigration on the adaptation strategies of households of origin, it aims to fill a knowledge gap for Senegal highlighted by Wade et al. (2017). It would be intuitively logical to assume that migration holds back rural development due to the departure of healthy, educated individuals. This might be especially true for Senegal, a country with a mainly agricultural economy, strongly dependent on climatic conditions. In the current context of environmental instability, a massive rural exodus is under way (Tandian, 2015). Based on empirical evidence, this study seeks to identify the adaptation mechanisms and strategies deployed by households in Gandiol and, more broadly, to see whether remittances actually contribute to the development of the municipality.
II – The situation in Gandiol
17Studies of sub-Saharan Africa have shown that in degraded rural environments where livelihoods are limited, some populations do not have the means to migrate permanently (Wiederkehr et al., 2018; Borderon et al., 2019). Faced with a lack of job opportunities and declining income, households may seek to adapt through strategies such as selling off livestock to reduce herd sizes, engaging in small-scale secondary activities, or changing their occupation. For those with the necessary resources, however, permanent migration of a household member offers a means to escape the spiral of poverty.
18In Gandiol, field data suggest that permanent migration is a direct consequence of the environmental degradation caused by the breach. In the past, migration was mainly circular and seasonal, linked to local fishing activities. Permanent migration appears to be a new strategy, designed to allow families to maintain their livelihoods in their home village (Tandian, 2015) supported by transfers of money, best practices, and technologies (Sall et al., 2011; GERM, 2017). While no statistics on international and internal migration are available to illustrate the new migration patterns in Gandiol, the skewed sex ratio reveals a shortfall of men in the population, lending support to this hypothesis. [4] In the most recent population census (2013), the country counted practically equal numbers of men and women, with a sex ratio of 99.4 men per 100 women (ANSD, 2013). A similar equilibrium is observed in the Saint-Louis region (99.5). In Gandiol, however, with a population of 21,182, the sex ratio is 80.2 (Table 1), which is much more skewed than at the regional or national levels. The imbalance is even greater for the 15–49 age group, with a sex ratio of 60.8 men per 100 women. In the 2002 census, the sex ratio was 90.2 in the 36 villages and hamlets (out of 39) for which data are available (ANSD, 2002). This sex imbalance grew larger between the two censuses, a period that witnessed the opening and widening of the breach. While we cannot formally conclude that the sex imbalance is due solely to male emigration in response to the opening of the breach, these figures do indicate a deficit of males in a context of environmental degradation.
Table 1 - Distribution of men and women by age group in Gandiol in 2013

Table 1 - Distribution of men and women by age group in Gandiol in 2013
III – Method
19The qualitative data were collected in the Gandiol municipality in July and August 2017. Thirteen villages (Figure 1) were selected to represent the main economic activities (market gardening, fishing, and livestock production) and the three main ethnic groups (Wolof, Fulani, and Moor). Only household members remaining in Gandiol and receiving remittances from one or more migrants were interviewed. By selecting these specific profiles and applying qualitative methods, we could collect data on representations of migration and migrant remittances and on migrants’ personal experiences, and highlight changes in migration characteristics as perceived by the interviewees. Sixty-four semi-structured interviews (36 men aged 20–85 and 28 women aged 18–64) were conducted, with the aim of representing different social groups.
20The fieldwork was conducted with a research assistant living in Gandiol and actively involved in the sustainable development of the municipality. He facilitated our relations with the customary authorities, and worked as our translator, as most respondents spoke little French.
Figure 1 - Study area

Figure 1 - Study area
21Each series of interviews in the various villages began with a meeting with the customary authorities to obtain the consent of the village head or to ask for advice on how to conduct the interviews to better understand the problems confronting the village. This initial exchange enabled us to contact village notables or resource people who helped us to identify individuals with the desired profile. These initial respondents then told us about other individuals who matched the criteria.
22This snowball sampling method has several limitations that make it difficult to propose an exhaustive typology of the complex interactions between remittances, migration, and adaptation. We could not ask questions about maladaptation (Barnett and O’Neill, 2010) or about failed migration-for-adaptation via migrant remittances. No interviews were conducted with households whose migrants do not send remittances, or with households with no migrants. It was thus impossible to determine whether households receiving remittances have specific characteristics regarding their networks and financial and material resources; for example, whether they are richer or better connected.
23After an initial analysis of the recorded interviews, nine common themes were identified. The excerpts that illustrate them were transcribed and grouped by theme, revealing four types of adaptation through migration. The excerpts were classified according to these four types, confirming the proposed typology. Our results are also based on field observations and informal conversations.
IV – Typology of the consequences of migration on strategies of adaptation to environmental change
24Illustrated by excerpts from the semi-structured interviews, this section presents a typology of the effects of migration on household adaptation strategies. We begin by describing the economic impact of La Brèche on respondents’ lives, in terms of soil salinization, physical danger to fishermen, and (in some cases) the emergence of household debt. We then present the household adaptation opportunities made possible by remittances, and identify three types of strategies: (a) income diversification that enables households to cover their daily needs and to repay their debts; (b) optimization of farming and fishing techniques to maintain a minimum livelihood; (c) construction of new dwellings far from the shore, and the development of basic infrastructure that gives a greater sense of security for local communities. Finally, we observed that a range of adaptation initiatives have been developed by women in response to changes in household structure resulting from male emigration.
1 – Economic consequences of the breach
25With the drop in fishing revenues due to the danger of crossing the breach, and the growing number of days when rough seas making fishing impossible, cash remittances offset a part of the lost income and serve to cover everyday household expenses. A fisherman from Tassinère and another from Pilote were asked what, for them, were the main environmental problems in Gandiol. Their answers illustrate the difficulties facing fishermen in Gandiol:
The main problem is the breach, which has made it more difficult for us to work. It’s tricky to cross. Several hundred people have died so far.
Now, there aren’t so many fish. Before the breach, we could catch lobsters in the river and fresh water fish. The river water is becoming more salty and there are fewer species, so I have to go further and further away. With the breach, it’s difficult to fish because of the currents, which bring in debris and dead tree trunks that damage my equipment.
28The salinization of the soil and groundwater has reduced crop diversity, yields, and frequency of harvests. In the past, the fields were within the villages, sometimes right next to the inhabitants’ dwellings. Today, the nearest arable land is several kilometres away. Farmers are forced to travel further and to dig ever deeper wells to find fresh water. With the deterioration of farming conditions, many fields have been abandoned. A market gardener, age 60, in Mbao village described salinization’s effect on his fields:
I have abandoned three fields because the soil is too salty. Many people have abandoned their fields. Before, I also grew potatoes, cabbages, and tomatoes. Now, I just grow onions, and my yields are lower. Before, you could get five to six tonnes per hectare. Now, I’m happy if a hectare produces three tonnes. Everything changed when the water became salty. My expenses are increasing because I keep having to change wells. The one I’m using now is more than 600 metres from my fields.
30The drop in income from fishing and market gardening has forced certain households to take out loans. A market gardener, age 52, from the village of Mboumbaye mentioned the emergence of debt problems when talking about the economic consequences of the breach:
More people started borrowing money, and a credit union was set up. Things were different before the breach. Before, we could save money, but now, people borrow. They use the loans to invest in fields and to cover everyday expenses.
32The emergence of debt reflects the decline in economic activities. Migration may thus be seen as an alternative to borrowing, but above all, as a viable option for ensuring a minimum level of subsistence.
2 – Remittances for diversifying income
33Coastal erosion and its consequences have reduced the incomes of the individuals we interviewed, whose livelihoods are highly dependent on their environment. In this context, migration and remittances diversify the means available for ensuring a minimum level of subsistence.
34Some fishermen have a tradition of circular and temporary migration to follow the movements of fish shoals. The breach has modified this practice. The remittances sent by one or more household members who have moved permanently to other regions of Senegal are sufficient to cover everyday household needs. When the migrants come home, they bring foodstuffs that are extremely expensive in the Gandiol region. The account of a fisherman, 52, from Tassinère shows how these two forms of support have become an income and food diversification strategy:
If the sea is rough and I can’t go out, the money I receive serves as a backup for my everyday needs. My son often sends money on a one-off or monthly basis, depending on his fishing income. When my son comes home, he also brings products that are cheaper in other regions, such as peanut butter or mangoes.
36A fish seller in Pilote, age 54, explained that she depends on remittances from her two children to buy her daily food supply. Her fisherman son has gone to work on the Petite-Côte, and her daughter lives in Spain with her Senegalese husband. ‘With the breach, there’s no fish any more. My husband can’t catch enough to feed everyone. So I use the money that my son and daughter send me for my everyday needs.’
37Environmental damage has not changed the mobility of market gardening households but has created new migration patterns. Among these populations, it is mainly the young men who have left, primarily to work in the urban informal sector. The onion seller, age 61, of Dièle Mbame explained why household members have to migrate to make a living:
Young people have left because they couldn’t find a job to support their parents. Before the breach, people didn’t leave because they could work at sea, in the river, or in the fields. My husband worked in the fields, but he can’t work any more. It’s one of my sons who has gone away to earn money to support us.
39Remittances provide a direct means to make up for loss of income due to salinization and lower crop yields. Reduced income has forced certain households to borrow from credit unions and to buy things on credit in local shops. Remittances enable households to repay their loans and lift the burden of debt, as pointed out by a Gandiol village head, age 75:
Local people can’t work in the fields any more. They often have to borrow from shopkeepers to eat because crop yields have fallen. Before, they didn’t borrow because our fields produced plenty of fruit and vegetables. We had enough money and enough food. But our sons’ money lightens the burden on our shoulders.
41Environmental damage caused by the breach has forced some households to diversify their income sources via remittances that play a dual role. The money sent by migrants covers households’ daily needs and enables those in debt to pay off their loans.
3 – Investment optimization
42Some market gardeners use migrant remittances to optimize cultivation techniques so that they can keep their fields and continue growing crops. In the past, fresh water could be found a few metres below the ground. Today, wells must be dug to a depth of several tens of metres and equipped with pumps. An onion grower, 65, in the vilage of Gouye Reine explained that he needed financial support from his son to continue his activity:
Sometimes, the cost of maintaining the equipment for my fields is so high that I have no money left to live on. When that happens, my son sends me money to cover the maintenance expenses. Without my son, I couldn’t afford to drill wells or buy a water pump.
44This transition to mechanized farming has enabled some vegetable growers to maintain a diverse range of crops and obtain several harvests each year.
45Likewise, some fishermen have used money from remittances to buy fishing gear adapted to the new environment and the arrival of new fish species. Powerful engines are needed to reduce the risk of capsizing when crossing the breach in heavy seas. The decrease in fish stocks has forced fishermen to go further out to sea and to stay out for longer, so larger boats are needed. Some fishermen have started to fish for new species, for which new nets and fishing techniques are needed. The words of a 50-year-old fisherman in Pilote illustrate the need to invest in new equipment:
The breach has caused much damage and loss of life. Many people have died because their boat capsized in the breach. Thanks to the money I’ve received, I could buy a larger boat. It’s getting hard to make a living because there aren’t many fish in the river. It’s better to fish in the sea at night, but it’s extremely dangerous to cross the breach in the dark. I’ve also had to learn how to use new nets, like bottom trawl nets or drift nets.
47Remittances can help households to optimize cultivation and fishing techniques, thereby safeguarding their long-term livelihood. Through optimization of this kind, inhabitants can adapt to a rapidly changing environment and lessen the impact of environmental degradation while maintaining technical skills and know-how.
4 – The protective role of remittances
48Successful migrants build houses in their village of origin with a view to returning home one day, either temporarily or permanently. These dwellings are usually large enough to accommodate the entire family. While consolidating ties with the origin community, this investment strategy also provides a refuge for the family in the event of coastal flooding. A village head, 68, recounted his experience in response to a question about the impact of emigration on the village:
Each generation has its own ideas. My generation didn’t think about leaving. Two of my sons are in Spain. One of them has papers, but not the other. He does casual jobs on the black market. It’s been 12 years since they left. One morning I got a text message: ‘We’re ready to go.’ The one with papers built a large house for the family far from the river bank. We’re safe now.
50For villages threatened by coastal erosion, remittances provide the means to build houses far from the shore, away from areas affected by coastal flooding. These constructions also contribute to development, particularly by improving village infrastructure. Water and electricity grids have been expanded to supply the new houses built in areas that previously had no basic services. For example, following the departure of the inhabitants of Doun Baba Dièye, the new neighbourhood of Boutou Ndour sprang up in the village of Dièle Mbame, and the whole village was connected to the electricity and water mains by the authorities. As a village male retiree, 70, explained:
Things started to develop when the new inhabitants arrived. Before, there wasn’t any running water or electricity, and there were no business activities. Now there’s water, electricity, a small market, and shops. It all happened very quickly. When new people moved in, they attracted more people, even from Saint-Louis, because there’s lots of flooding in the town during the winter.
52On the same topic of development, a marabout in Gandiol, age 47, pointed out that migrant remittances are often associated with transfers of knowledge that are helpful for the village economy:
Departures mean opportunities since everything the migrants earn comes back to the village. It’s a big step forward in the village. They go away, they learn something new, and it comes back to the village. When they earn money, it makes their families’ lives better. Before, we lived in tents, and now we have houses.
54A village head in Gandiol, age 66, mentioned the concepts of happiness and bounty. Infrastructure protection appears to strengthen the sense of well-being in the village:
It was when people started leaving that happiness came to the village. Now that the young people have gone, we can do things we couldn’t do before. We can respond more quickly when there is a disaster or when we have to repair a building because we know we’ll find the money. The departure of young people is a great development in the village.
56Building new houses requires labour. The pace of construction is slow, however, and extends over several years, so jobs in this sector are intermittent and non-permanent. Migrant remittances also serve to maintain existing dwellings and to renovate or build community buildings. In Tassinère, a retired fisherman, age 71, described what he saw as the positive link between migration and village development: ‘The houses began a few years ago. The houses are built in stages. The departure of young people is a good thing. This allows the village to develop, as it gives work to build the houses.’
57Several forms of adaptation come into play for the protection of people who stay in the villages. New housing funded by migrant remittances protects families by moving them away from the shoreline. The construction of new homes in safer areas has led to improved basic infrastructure, but also provides casual employment. Last, infrastructure development in the villages seems to provide a stronger sense of security.
5 – Consolidation through increased female employment
58Because of environmental degradation, many men have migrated elsewhere to support those who stay behind. To make up for their absence, women have started to assume new responsibilities and exploit new economic opportunities. By taking up paid employment, some women have broken away from the traditional patriarchal structure of the home and developed new livelihoods that reinforce the household’s adaptation capacity.
59With the increased salinity of the Senegal River, the area has been colonized by shellfish and oysters. Some women now collect and process them for sale in inland areas of Senegal and in neighbouring countries where seafood is difficult to find. The female president, age 43, of the economic interest grouping (EIG) in Gandiol described one of the effects of male emigration on female employment: ‘With their husbands away, the women here are gaining new freedoms and coming out of their homes to work. They often collect shellfish and oysters in the river.’ A fisherman, age 52, from the village of Keur Barka highlighted the importance of female employment for household survival: ‘Yields have fallen by half. The young people leave because there’s no work. Before, women didn’t work so much. Today, now that their husbands have left, they have to work to earn money every day.’ A woman in the village of Dégou Niayes, age 49, explained that she can’t grow crops in her field because the soil is too saline. Her husband left to go fishing on the Petite-Côte, and with the money he sends back they have extended their house. She harvests shellfish in the river, and this new job brings in enough money for her daily needs:
My husband has gone away to fish on the Petite-Côte. He comes back once a year with the money, and we use it to extend our house. When I really need it [money], he sends it to me. But I have to cover the daily cost of feeding my children. I can’t use the field in front of my house any more, so I decided to catch shellfish and oysters. But it’s very hard work.
61The physical demands of these activities may limit their emancipatory effects, however. Some women may be reluctant to engage in strenuous work of this kind and remain dependent on other sources of household income.
62Women also do other types of work. For example, EIGs have been set up to run flour mills. They also operate as small-scale micro-credit agencies, enabling women with limited employment opportunities to borrow money to launch a small business. A 54-year-old vegetable seller on the Mbao village market explained how the EIG helped her to open a small shop:
There is a big rural exodus of young people because of the breach which has taken away all the jobs. There aren’t many work opportunities for women. That’s why we have set up an EIG. Only the women stay in the village. Before, women could work in farming. Lots of us have lost our fields because of the salt. As the men are all gone, you have to look for solutions yourself and find ways of making money. So I decided to open my shop and I got financial support from the EIG. With the salty water, I can’t find good quality vegetables any more. I have to take a taxi to buy good vegetables.
64Other women have chosen to work for large vegetable suppliers in the Senegal River valley. This farm work makes life complicated for families, however, and the pay is low, so it is generally an option of last resort. When asked about alternative jobs that she could do, a woman aged 36 in the village of Geumbeul who picks beans on a seasonal basis for a large vegetable supplier described her arduous working day: ‘I work for a company picking beans. I have to fill three crates to earn 2,000 CFA per day. I have to leave at 4 a.m. and I get back at 6 p.m. The work is really hard, and the season is short.’
65The salinization of the Senegal River has also generated some new economic opportunities. Some women earn a regular income by selling the shellfish and oysters that have recently appeared. Others have formed EIGs to develop their activities and create new jobs. Those without new income sources can find lower-paid jobs in private businesses. By breaking away from the traditional patriarchal structure, women have reshaped the system of economic production and now help to ensure a stable household income.
Conclusion
66The opening of the breach in the municipality of Gandiol provides a textbook case for studying the impact of migration on adaptation strategies. The breach and its environmental and social consequences are both ‘sudden onset events’ and ‘slow onset events’ (Privara, 2019). Coastal erosion is often a sudden phenomenon resulting from flooding that destroys habitats and ecosystems. Coastal flooding, on the other hand, results in gradual processes of soil and groundwater salinization that build up over time. Climate change is predicted to accelerate the overall processes of erosion and of soil and groundwater salinization. Gandiol thus provides an opportunity to study different types of hazards occurring simultaneously in the same place.
67It is difficult to dissociate the effects of environmental change on a population from those of societal change. This is especially true when seeking to determine the role of environmental factors in the decision to migrate. Environmental and societal impacts are intertwined, as are their effects on the living conditions of a population. The case of La Brèche illustrates the environmental consequences of coastal erosion in West Africa. Its social consequences are less clear-cut, however. Case studies with a direct or indirect focus on coastal erosion and migration in the region are rare (Dossou and Glehouenou-Dossou, 2007; Codjoe et al., 2017; Ozer et al., 2017; Zickgraf, 2018). However, as this article has shown, local inhabitants clearly understand the consequences of the breach on their living conditions and the importance of migrant remittances. Our hypothesis of a link between environmental degradation and male emigration in Gandiol is thus confirmed. This male exodus has produced societal changes due in part to the deficit of men in the population.
68Our interviews revealed how migrant remittances are used over the short, medium, and long term. They serve primarily to complement household income, as observed elsewhere (Tacoli, 2011; Lo et al., 2014; Lalou and Delaunay, 2015; Tandian, 2015; Wade et al., 2017; Zickgraf, 2018; Sakho et al., 2019). This strategy plays a dual role in short- and medium-term adaptation. First, it provides a means to satisfy basic needs at a time of environmental shocks. For households with debts, the additional income serves to pay off their loans. Investment in new farming and fishing techniques is an optimization strategy enabling households to secure a stable minimum income while reducing the risk of dependence on remittances. It also provides a means to safeguard existing know-how.
69The construction and renovation of houses and community buildings play a protective role on several levels. As well as providing homes for families away from coastal flood zones, it also provides work for inhabitants. This point ties in with a general observation that migrant investments in property have changed Senegalese village landscapes (Wade and Wade, 2018) and stimulated the construction sector (Tandian, 2015). These protection strategies are probably effective over the long term as they contribute to a stronger sense of security.
70Last, large-scale male migration has modified the division of labour and challenged traditional patriarchal structures. Women’s involvement in income-generating activities guarantees a minimum long-term income for families and promotes female employment (consolidation). This analysis shows that remittances provide a stimulus for development in Gandiol. However, all our study participants received money from a household member who had migrated, so these findings cannot be generalized to all households in the study area.
71While diversification strategies have already been described in the literature, optimization, protection, and consolidation strategies are less well documented. This study aims to shed new light on population adaptation via migration, in a context of environmental degradation. While described separately, these strategies of adaptation through migration may well operate in combination.
72A typology provides a clearer picture of the phenomenon through more schematized overviews of complex crises. This makes comparison simpler and may bring to light more cross-cutting information both for Senegal and for West Africa. The typology provides a reference framework for studying the impact of adaptation strategies on population change in West African coastal communities affected by environmental degradation.
73The literature has focused on remittances sent by migrants from OECD countries. However, studies of environmental migration in West Africa have shown that climate change and environmental degradation may make international migration more difficult (Henry et al., 2004; Brüning and Piguet, 2018; De Longueville et al., 2019) while driving internal migration within a country or subregion. Climate change often makes it more difficult to acquire the substantial resources needed for international migration. It would therefore be useful to shift the research focus towards internal remittances.
74The first task would be to determine the volume of these financial transfers, their nature, the internal transmission channels used, and their impact on adaptation strategies so that any differences with respect to international transfers can be identified. Qualitative studies would then be needed to understand how the perception of internal remittances influences the way adaptation strategies are implemented. Remittances are not necessarily unidirectional, since migrants may receive money from their household of origin. It would be useful to study the contexts of these remittances and their use. Because migrants who arrive in a new destination bring their own practices and norms with them, it would also be helpful to study the effects of the arrival of new individuals and the consequences of immigration on the adaptation capacity of populations in destination societies.
75Africa is the continent most vulnerable to environmental variations (IPCC, 2007), so we can expect migration to increase—mainly within countries and subregions—especially in West African societies where mobility is strongly rooted in local cultural structures (Mortimore, 1989). To plan for adaptation in a context of coastal degradation, more information is needed on the social processes involved (Curtis and Bergmans, 2018). Data of this kind are important for Senegal, where coordination is lacking and public policies are fragmentary (Wade et al. 2017), especially when it comes to planning for climate change adaptation.
Appendix
Saint-Louis and the municipality of Gandiol in 2003

Saint-Louis and the municipality of Gandiol in 2003
Saint-Louis and the municipality of Gandiol in 2016

Saint-Louis and the municipality of Gandiol in 2016
Notes
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[1]
The Langue de Barbarie is a sandbank measuring around 30 km in length that separates the Senegal River from the continent.
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[2]
See Durand et al. (2010) for the construction of the breach and its efficacy; Rey and Fanget (2017) for a critical assessment of its construction; Sy et al. (2015) for its hydrogeomorphological development. For maps of the area, see Appendix.
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[3]
To select the case studies for this article, we used the Climig Database (https://www.unine.ch/geographie/climig_database), an online bibliographic research tool developed by the Institute of Geography of the University of Neuchâtel. It lists all publications in the field of environmental migration. We used Africa and Senegal as keywords before selecting the articles manually.
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[4]
The sex ratio is the ratio of males to females in a population. It is expressed as the number of males per 100 females. A figure above 100 indicates a male majority, while a figure below 100 indicates a female majority. https://www.ined.fr/en/glossary/sex-ratio/