2. People and their Activities: Babel and Cocagne
p. 149-163
Texte intégral
1The conditions in and around Lake Chad described above have resulted in a significant level of settlement and the development of original and productive systems of activity, both on its islands and along its shores. When the Lake transitioned into its Little Chad state in 1973, its riparian societies—including people who carried on family occupations as well as many migrants of various origins—developed adaptive strategies generally based on mobility, making the most of the environment’s resources through varied forms of fishing, livestock farming, and agriculture. They also proved to be remarkably innovative and responsive to demand from urban markets: Lake Chad became an export hub for fish, livestock, and agricultural products and now plays a major role in regional food security. But this success comes with a price: increased pressure on space and resources has made it necessary to intensify productive activities and fine-tune regulations across activities and regions in order to prevent and manage conflicts.
An inhabited Lake
2Today, Lake Chad is the site of a major concentration of people in the central Sahel region. However, little is known about its demography: firstly, because the environment’s features (its variable nature, population mobility, and cross-border location) make it difficult to carry out a census. Understanding how many people depend on Lake Chad is further complicated by the issue of deciding the extent of the area to be studied.
3By following the administrative divisions that are used to create censuses, we have selected three groups which differ from one another in terms of the intensity of their trade and migratory relationships with the Lake:
4The first group is made up of the island populations, inhabitants of the Lake’s shores, and those who live in the immediate hinterland (up to around 30 to 40 km from the shore). This area corresponds to a circle with a radius of approximately 100 km extending from the point where the Chad-Cameroon-Nigeria tri-border area, which is roughly the Lake’s current geometric centre (Figure 6). It includes people who make their living, for the most part, directly from the Lake’s natural resources through fishing, livestock farming, and/or agriculture, either on a continuous basis or through seasonal migrations. As of 2013, this group included more than 2 million people.
5The second group includes a wider area with a radius of approximately 300 km. It covers the main area where products from the Lake are sold, as well as a major seasonal migration area, although it is not as exclusively centred on the Lake. This area includes the two urban centres in the region, N’Djamena and Maiduguri, as well as the largest administrative entities around the Lake (Nigeria’s Borno state and Diffa region, Cameroon’s Far North province, and Chad’s Lac, Kanem, Hadjer-Lamis and Chari-Baguirmi regions). However, within these regions, there are some highly populated areas that only interact with the Lake intermittently, or not at all, as is the case in the Mandara Mountains. As of 2013, there were 13 million people living in the Lake’s extended hinterland area.
6The third group corresponds to Lake Chad’s conventional basin, the area under the LCBC’s jurisdiction. Beyond the second circle described above, people have only tenuous relationships with Lake Chad. Nevertheless, products from the Lake are sometimes sold in these outlying areas, such as smoked fish or live cattle in Kano, although these products only play a minor role in supplying the areas in question. Occasional migratory flows of fishermen or farmers have been known to pass through these areas. As of 2013, this area had 47 million inhabitants.
7Populations are relatively dense in the areas around Lake Chad, particularly when compared with other neighbouring Sahel regions. Average population density is 50 people per km2. There is a significant difference between population density around the northern basin and shores (fewer than 20 people per km2) and around the southern shores (more than 60 people per km2). This difference is a product of the advantages of the southern shores: water is available on a more consistent basis and the area is better connected to the active urban regions to the south.
8The Lake is one of the rural areas that have seen major population growth over the last few decades. The population in the first circle defined above rose from 700,000 in 1976 to 2 million in 2005. The transition to the Little Chad state was accompanied by an average annual rate of growth that was slightly higher than the natural balance—around 3.2% per year. This means that overall the migratory balance is positive: the Lake attracts more people than it loses to rural exodus. This rate of growth is higher than 4% in some of the more attractive areas on the southern shores. Conversely, it is lower in the areas around the northern shores.
Figure 6. The population of the Lake and its regional environment.
Source: authors. Produced by: O. Ninot.
9The Lake and its shores were relatively un-urbanised: as of 2013; around 30 small towns accounted for less than 15% of the population. But the Lake falls within the sphere of influence of the region’s two major urban areas boasting populations of around 1 million inhabitants as of 2013: N’Djamena (1,150,000) and Maiduguri (900,000).
10With population growth expected to continue in the area immediately surrounding the Lake as well as in the rural and urban hinterlands, understanding the systems of activities that have been developed by riparian societies is essential for meeting regional food demand, while also taking into account their constraints and limitations.
Mobility and systems of activities
11The area around Lake Chad has never been so densely populated. During much of its history, the Lake’s population fluctuated. This nearly permanent water table, located at the 13th parallel north, has polarised populations at least since the Holocene era—i.e. for 10,000 years. However, major climatic variations throughout the region and around the Lake itself have also motivated people to leave. This was the case during periods of drought, or, conversely, during wetter periods which diminished the utility of its resources. Furthermore, in the pre-colonial period, although the Lake served as a refuge for people attempting to escape the authority of the Kanem-Bornu Empire, its southern shores were very sparsely populated due to fear of the Buduma island dwellers (Bouquet, 1990). In addition to this group, the shores of the Lake were home to small numbers of neighbouring populations: the Kanem in the north-east (Kanembou), the Borno in the south-east (Kanouri), the Mobber of the Yobe River, and the Choa Arabs and the Kotoko in the south on either side of the Chari River delta.
12The 20th century was marked by a movement of gradual colonisation, a trend which has accelerated since the transition to the Little Chad state in 1973. Migration to the Lake is inextricably linked to growing economic opportunities for exploiting natural resources. Migration started with fishing communities in the 1930s in Nigeria, and then in Cameroon and Chad in the 1950s. The decades of drought in the 1970s and 1980s saw the number of migrants grow even higher. Many of the migrants at that time were crop farmers, who migrated there with fishermen and livestock farmers, leading to a very mixed, cosmopolitan population, especially on the southern shores that attracted the largest number of migrants. During this influx of populations, groups who had been settled in the area for a long time moved closer to the Lake (Kanuri, Shuwa Arabs, and Kanembou) and mixed with migrants from further afield (Hausa, Fulani, Sara from southern Chad, mountain dwellers from Guera in the 1980s, Ouaddai people during the 2000s, and West African fishermen of various origins). The siting of communities, permanent villages, and temporary fishing stations and livestock camps evolved to adapt to the Lake’s changing water levels. Between 1965 and 1985, a period in which the Lake decreased in size, former seasonal camps became permanent villages and new temporary sites were built in areas that had formerly been covered by the Lake. This trend then reversed when water levels began to rise again.
13Natural potential, local knowledge, and growing urban opportunities encouraged the development of original and productive systems of activities based on population mobility and agricultural pluriactivity. Many of the Lake’s residents make their living by combining fishing, agriculture, and livestock farming. The importance these people attach to each of these activities varies according to the season or the year (depending on whether the water level is high or low), where they live, their geographic and cultural roots, their access to natural resources (land tenure rights), and the available capital and labour. Each year, the region sees both internal seasonal migration—Buduma islanders farming in the Bol polders, inhabitants of the southern shore fishing in open water, etc.— and migration from the region’s hinterland or even farther afield. The greatest mobility of populations is seen in the northern basin, where flood variability is at its highest: during flood recession and low-water periods, its inhabitants live along the estuary of the Yobe River or migrate to the southern basin, where they fish in open water or work as temporary labour on the fertile floodplains. When severe flooding occurs, the northern basin attracts many fishermen from all over the region and its surrounding areas. When flooding is moderate, the people from the Nigerian hinterland (Manga, Kadzell, and the Diffa region) move there to cultivate the land. Thus, mobility enables workers to optimise their production according to the Lake’s water level, which determines the location of natural resources.
14Locally, this pluriactivity is enhanced by the exploitation of other natural resources (see III-4). These local resources—spirulina to the east of the Bol archipelago, natron around the Lake and in Kanem, and timber at the centre of the northern basin and in the Chari delta—provide work to thousands of people and, most notably, act as sources of income for individuals with little capital (in terms of land, livestock, or fishing equipment). Some of these activities, such as harvesting natron, are quite ancient; others are more recent. Spirulina has long been regarded as “green gold” that could solve part of the food security problem in the northern Sahel region. The future of existing industries needs to be secured and the balance between regional markets and exports improved. Selling the timber grown around Lake Chad involves very specific challenges. Although logging must sometimes be limited to prevent the loss of biodiversity, such as in the Chari delta, it can also be useful and can be a major part of the Lake’s economic model. Stands of Prosopis, which prospered during dry periods in the northern basin during the Little Chad period (see I-1), were wiped out when flooding returned in the last relatively wet climate sequence (1991-2013). Clearing the dead trees then freed up land for agriculture while providing a valuable resource for the fish-smoking industry.
15Vast areas affected by the Lake’s drawdown are cleared and cultivated as the Lake recedes, freeing up fertile land and rich pastures. The space is used in different ways in order to maximise its value. The same space can be used, successively and according to water levels, for fishing, agriculture, and livestock farming. How this space is used follows a concentric logic: flood recession agriculture occupies the outer shores (Figure 7). As one moves towards the centre of the Lake, where the risk of early flooding is high, there is a shift from agriculture to livestock farming and fishing. Conversely, as one moves away from the Lake, land cultivation becomes less intensive and livestock farming more prevalent. As growing population densification increases the pressure on the best land, conflicts between activities escalate, especially when the level of the Lake changes compared with previous years. Livestock farming tends to be pushed back towards the islands of the Lake or towards its exposed periphery.
16Regulating access to resources is therefore a central issue. Because of slow, uneven progress with the decentralisation process in the four riparian countries, access to resources is still largely regulated by customary systems. These customary systems do not have a centuries-old heritage of sophisticated rules as is the case in Mali’s Inner Niger Delta. In some areas, however, the rules governing access to resources bear the mark of former territorial control systems, such as along the northern shore inhabited by the Kanembou in Chad, in the Kanuri chiefdoms in Niger, or on the Buduma islands. Moreover, low population density around the Lake left a void in terms of rules governing land tenure. The 20th century saw a gradual decline in the power of customary chiefs in these pioneering areas, alongside the waves of migration that developed them. The receding water levels that began in the late 1960s and the accompanying settlement movement paved the way for the establishment of new rules governing the allocation of fishing sites, livestock corridors, and floodplains. These measures were accompanied by greater inequality and the exclusion of certain groups (young people, recent migrants, mobile groups such as livestock farmers, etc.), which occasionally led to conflicts.
17The existence of conflict is not surprising in an area such as Lake Chad. After all, the Lake has abundant resources and an unstable environment; it is shared by four states and multiple customary chiefdoms; it has also attracted many migrants of different origins who simultaneously practise fishing, agriculture, and livestock farming. These conflicts have several causes: the interplay between customary and modern rules that is often found in West Africa, involving chiefs, local authorities, and government departments; migrants questioning the legitimacy of customary rules; and, most originally, the uncertainty surrounding boundaries (between parcels of land, customary lands, and even countries (see III-1)) caused by a shifting environment and changing shorelines. Against the backdrop of demographic growth and increasing pressure on resources, there is a pressing need to draw up clearer, more legitimate rules of access to resources. The cosmopolitan nature of the people living around the Lake argues in favour of replacing rules based on autochthony with mechanisms that enhance the relationship between local citizenship and the rights of mobile groups.
Figure 7. Multifunctional spaces.
Source: RAIMOND and RANGÉ (Atlas du lac Tchad, forthcoming).
Productive activities between innovations and markets
18The efficient systems for exploiting the Lake’s resources were made possible by successive innovations in each of the three main activities (fishing, agriculture, and livestock farming). Generally endogenous, these innovations were designed to meet the demand of regional markets, especially in urban areas. As a result, Lake Chad is currently a major exporter of various food products and plays an important role in supplying the cities and the countryside of its extensive hinterland.
19Lake Chad was once an El Dorado for fishing. It benefits from its position as the collection point for water in the basin at the bottom of its hydrologically active area. Its warm, shallow, mostly fresh water, connected to the Chari-Logone floodplains, is particularly favourable to fish reproduction. Fishing did not really take off here until the 1930s. Improved transport networks in Nigeria and the arrival of fishermen and Igbo middlemen, who introduced the technique for making banda (smoked fish), then made it possible to export fish from the Lake to urban consumer markets in southern Nigeria. In the 1950s, people from southern Chad followed the Chari and settled at Lake Chad in order to fish there. Some migrants, including the Hausa, brought with them new equipment and new fishing techniques. The use of nylon lines and large motorised canoes became widespread. In the 1970s, droughts led to a massive influx of fishermen, some of whom travelled great distances (from Senegal, Mali, Ghana, etc.). For a while, the drying up of the Lake provided excellent fishing opportunities (1970s). Then fishing seemed to come to a halt and many fishermen turned to agriculture. The dissemination of a new technique imported from Mali—the use of fish fences, or dumba—made it possible to adapt to new environmental conditions, marked by a decline in the amount of open water available and an increase in marshlands. This new technique resulted not only in larger catches, but also in new fishing rights favouring the most powerful, which sometimes led to tensions. In some sectors, such as that of the local government of Marte (Nigeria) migrants (in this case Hausa) managed to supplant the Kanuri, who traditionally controlled the water.
20The success of the fishing industry relies on effective organisation designed to ensure the effective catching, processing, and long-distance trade of this perishable product. Traders and fishermen are mutually dependent on one another: traders provide fishermen with equipment on credit and in return depend on them to supply the fish. The activities of smoking and drying fish are the lifeblood of many islands, fishing stations, and wharfs. Parallel to these activities, trade routes for selling fresh fish have been established over the past twenty years. Every day, several tonnes of fish caught near the Chari delta or the Baga-Kawa wharf in Nigeria are sent to N’Djamena and Maiduguri. It is estimated that the Lake produces between 50,000 and 100,000 tonnes of fish per year, depending on the year and the source consulted. The entire industry (fishing, processing, transportation, wholesale and retail trade, etc.) provides employment for many people, estimated at between 200,000 and 300,000, including the number of induced jobs.
21Public policies designed to boost the fishing industry have had mixed results. Isolated attempts by cooperatives, notably in Chad and Cameroon (1950s to 1970s), to regulate production and commercialisation have not been successful. The main effect of coercive measures against prohibited fishing gear was to line officials’pockets with the fines imposed on fishermen. The value of these measures is questionable in environments where annual flooding is the main factor for resource renewal. Improving storage and transportation conditions is key to driving growth, providing income to the Lake’s fishermen, and feeding urban populations.
22Lake Chad’s agricultural potential was identified at the time of independence, but it was primarily taken advantage of by local farmers with little government backing during the transition to the Little Chad state in 1973.
23Between the 1950s and 1970s, Lake Chad was the site of major ambitions for irrigation (Figure 8). In Chad, inspired by former Kanembou land development initiatives—“polders” where interdunal branches were separated from the Lake by erecting earth dams for a number of years—the government aspired to use modernised polders to develop a breadbasket for the country. The project fell far short of initial expectations, owing primarily to a political crisis that engulfed the country, among other constraints. Nevertheless, SODELAC (Lake Development Company) managed to develop a few hundred hectares of “modern” polders (with full pump-driven water control). During the 2000s, several thousand hectares of semi-modern polders were also developed. Operated by farmers under the supervision of SODELAC, they proved quite productive. Maize replaced wheat in almost every area. In Nigeria in the 1970s, two very large projects were implemented: the South Chad Irrigation Project (SCIP) and the Baga polder project. The results were disastrous. Finished at a time when the Lake had receded by several kilometres, the two sites have hardly ever been used (Bertoncin and Pase, 2012).
24Lake Chad’s contemporary agricultural boom is intrinsically linked to its transition to its Little Chad state that began in 1973. Flood recession cultivation existed in the early 20th century, but to a limited extent, owing to the Lake’s sparse population. In several major waves corresponding to the peak drought periods (1973-1974 and 1984-1985), migrants, driven from their homelands by famine (and sometimes by war, as in Chad in 1984), started to cultivate the lands exposed by the receding Lake. Demand from urban markets, which has grown with the development of regional cities (N’Djamena and Maiduguri) and even demand from markets farther afield (throughout Nigeria), has encouraged the production of new crops and contributed to the gradual specialisation of certain areas. Maize is grown everywhere; it dominates Lake Chad along its southern shore, the Bol archipelago, and the polders, as well as the northern Nigerien basin when the water levels are high. The Nigerian shore is strongly geared towards cowpea production, which is also prevalent in the agricultural systems in the northern Nigerien basin (especially when the water level is moderate to low). Along the Yobe River, a small basin specialises in the irrigated production of peppers for the Nigerian market. In the Chari delta (Chad and Cameroon), farmers cultivate a variety of plants, with a strong market gardening focus meant to supply the N’Djamena market (tomatoe, lettuce, carrot, watermelon, sugar cane, okra, sweet potatoe, onion, cassava, etc.), and with more diverse channels that are used in case of market saturation (transporting to Kousseri and Maroua in Cameroon, to Nigeria, or to other cities in Chad).
Figure 8. Irrigation in the Lake Chad Basin.
Source: BERTONCIN and PASE (Atlas du lac Tchd, forthcoming).
25Most of the innovations have been endogenous, although some were initiated or facilitated by support services—in Chad, for example, the Catholic Relief Services for Development (SECADEV), an NGO, distributed vegetable seeds and small equipment to “climate refugees” who migrated to the southern shore in 1984. The rise of these new crops was accompanied by widespread use of certain inputs, such as pesticides, from private channels that source their products in Nigeria. Fertilisers are not necessary, given the fertility of the land. These innovations also involve the implementation of minor land development projects for managing moderate flood variations: traditional polders, but also dykes to protect fields from early flooding, or channels used to “pull” the flood waters to land located far from the Lake by means of small irrigation equipment. On Lake Chad’s southern shore, animal-traction farming still exists; some attempts at mechanisation were made in the late 2000s. The mobilisation of a large seasonal workforce makes it possible to cope with peaks in work (clearing, weeding, and harvesting) on land where the sequence of activities (different crops, but also livestock) and the rhythm of the Lake’s rise and fall make it necessary to make the most of short time windows.
26There is a clear need for better support for farming around Lake Chad in order to meet the food challenges of tomorrow. There is still land potential in the isolated Bol archipelago and in the northern basin, which is exposed to the Lake’s irregular flood patterns. On the southern shores, increasing production means increasing productivity. There are certainly areas where intensification is possible, though this would require “traditional” support for farmers (agricultural extension services, credit, quality control of pesticides, an improved post-harvest chain, etc.), clarification of land tenure rights, and the creation of coordinated rules for managing areas, so that agricultural densification does not come at the expense of livestock farming.
27Livestock farming has developed around Lake Chad alongside this growth in fishing and agriculture. This activity involves protean realities that are not easy to understand, let alone quantify, given the mobile nature inherent to the activity and livestock farmers’ well-known aversion to censuses. Some live permanently on the Lake’s shores and islands, having moved there during the droughts in the 1970s and 1980s; others stay there temporarily for varying lengths of time as they follow transhumance routes of varying lengths; while others use it as a transit area between Sahelian routes and Nigerian consumer markets. As a result, the livestock farming systems that can be found vary greatly: there are the Buduma islanders, whose economic success in agriculture and fishing have created such large herds that they are forced to leave the Lake for longer periods of time and travel greater distances than in the past. Similarly, many sedentary farmers and fishermen, including the Kanembou and the Kanuri from the regions of Diffa and Bornu, capitalise on cattle breeding and entrust their animals to herders travelling near the Lake. The Hausa are known for fattening cattle. In Chad, rich city dwellers invest in livestock and choose the Lake for the quality of its pastures and its proximity to N’Djamena. Arabs practice both agro-pastoralism (Shoa) and transhumance. The nomads are Toubou and Arab camel drivers in the northern Nigerien basin, the Kreda from Kanem on the southern Chadian shore (with cattle, camels, and small ruminants), and above all different groups of Fulani.
28The Lake has been a place of such pastoral polarisation because it provides unparalleled water and foraging resources (flood recession pastures and crop residues) in the region with relative certainty and on a year-round basis. The contrast with the degraded environment of the northern part of the Lake is especially stark. This area has been the most severely affected by drought (northern Nigerian and Chadian shores) and its grassy and woody flora have only been partially reconstituted after the 1970-1980 drought. The attractive features do bring with them a sanitary environment that, like any other marshland, is very disadvantageous for livestock farming, including biting insects that are vectors for pathogens and questionable water quality. On the edges of the Lake, the herds move both radially—approaching the water as it recedes and as dictated by local farming schedules, then moving away from it in the rainy season—and circularly, as many groups travel from Chad or Niger to Nigeria’s commercial outlet by moving around the Lake’s edge.
29Despite the attractiveness of the Lake for livestock farmers, the concentration of herds there is often described in crisis terms. Analysis (see III-2) calls for a nuanced diagnosis. The negative impact of livestock farming on the environment has not been definitively proven. In the northern part of the Lake, livestock farmers are both responsible for and victims of deforestation. To the south, it seems that livestock farming is contributing to the regeneration of plant cover. Livestock farming is certainly linked to many conflicts between livestock and crop farmers as well as, quite often, between groups of livestock farmers. For instance, the Buduma from the islands defend “their” pastures from the Fulani, a group of Arabs from northern Cameroon, considering themselves to be at a disadvantage vis-à-vis the more agile Fulani zebus, and therefore prevail on the government to detain Fulani herds at the Chadian border for weeks. To date, however, these conflicts have not reached the degree of violence seen in other regions of the Sahel (like Darfur) and local solutions or environmental changes often defuse these conflicts—a significant flood is sometimes enough to temporarily solve problems of access to resources. Livestock farmers are especially vulnerable to insecurity and racketeering, which led some of them to leave Nigeria for Cameroon in 2012-2013. Additionally, livestock farmers suffer from the lack of treatment capabilities on the part of veterinary services. These have been cut back as a result of structural adjustment plans and their treatment mechanisms are unsuited to the Lake’s special characteristics (diseases and movement) and they don’t take into account the area’s importance for regional livestock farming.
30Agricultural densification, which accelerated in the 1990s, is undoubtedly the main challenge facing livestock farmers. Most notably, this densification has led the largest livestock farmers to graze on unhealthy marshlands, which bring with them particular new risks such as food-borne diseases resulting from the excessive use of dangerous plant protective agents. Despite these problems, however, grazing pressure has continued to increase at the Lake, indicating that the relative benefits offered by this area outweigh its drawbacks.
31In view of the continuing growth of human and animal populations around the Lake and in its surrounding regions, there are available tidal range areas with agricultural or foraging potential that could be put to better use, especially on the northern shores of the southern basin (Bol archipelago) and in the northern basin. Forage crop experiments conducted in polders have produced exceptional results in the past. Just as with agriculture, an examination of the intensification of livestock farming is necessary. The challenge consists of first making livestock farming systems function securely (health, clarifying land tenure, marketing, etc.) and then supporting changes in herding methods through technical improvements.
32The marketing of agricultural products (fish, grains, market gardening products, and pastoral products) and other natural resources from the Lake (natron, timber, spirulina, etc.) is largely carried out by informal ethnic networks of merchants. Though some ethnic specialisations are long-standing and lasting (for fish trading this includes the Hausa and the Kanuri in Nigeria and the Kim and Sara dealers in N’Djamena), the growth and increasing sophistication of the flows seems to limit monopolies. Through an organisational structure that remains largely unknown, influential large urban traders exist alongside energetic traders with fewer stocks who often operate intermittently and live in rural areas or in the towns near the Lake. Collection happens through a dense network of weekly, relatively hierarchised markets that enable products to be grouped and transported to the main consumer markets of N’Djamena and Maiduguri. The relative specialisation of these markets reflects that of the Lake economy: fish dominate the interior of the Lake (Kinasserom in Chad, Darak in Cameroon, Doro Lelewa in Niger, and Baga Kawa in Nigeria), agricultural products dominate the outer shores (Karal and Gredaya in Chad, Blangoa in Cameroon, Bosso and Boulatoungour in Niger, and Wulgo and Monguno in Nigeria), and pastoral products dominate the immediate hinterland (Rig-Rig, Bol, Massaguet, and Massakory in Chad, Mada and Madaick in Cameroon, N’guigmi in Niger, and Gambaru, Kirenowa, and Monguno in Nigeria) (Figure 9).
33The Lake makes a significant contribution to regional food security, though it is rarely identified in the literature, much less quantified. Maize production by the 2 million inhabitants of the Lake is estimated at between 600,000 and 900,000 tonnes per year (see the calculation methods in III-1). Assuming that the inhabitants of the Lake consume around 330,000 tonnes of grain, there is a remaining surplus of 270,000 to 570,000 tonnes to supply N’Djamena and Maiduguri (total consumption of around 330,000 tonnes) and the rural hinterland that often have deficits, such as Chad’s Kanem region, Niger’s Manga and Kadzell regions, Cameroon’s Serbewel region, or the northern part of Nigeria’s Borno state. The Lake also provides animal proteins that are competitive with imports and suited to local diets; it exports large quantities of fish, mainly smoked (to Nigeria), but also dried (to North Cameroon) and fresh (to N’Djamena and Maiduguri). It also plays an important role in the regional flows of livestock between the Sahel (Chadian and Nigerien) and Nigerian consumer markets.
34A dynamic equilibrium is therefore established between an environment characterised by its variability and high-performing systems of economic activity aimed at satisfying the needs of regional urban markets. Public policies must find a way to support the sustainable intensification of these systems without undermining the factors that make them so effective—i.e. mobility, multifunctionality, and pluriactivity.
Figure 9. Transportation on the Lake.
Source: MAGRIN and BOUVAREL (Atlas du lac Tchad, forthcoming).
Le texte seul est utilisable sous licence Licence OpenEdition Books. Les autres éléments (illustrations, fichiers annexes importés) sont « Tous droits réservés », sauf mention contraire.
Substances naturelles en Polynésie française
Stratégies de valorisation
Jean Guezennec, Christian Moretti et Jean-Christophe Simon (dir.)
2006
L’énergie dans le développement de la Nouvelle-Calédonie
Yves Le Bars, Elsa Faugère, Philippe Menanteau et al. (dir.)
2010
La lutte antivectorielle en France
Didier Fontenille, Christophe Lagneau, Sylvie Lecollinet et al. (dir.)
2009
Le mercure en Amazonie
Rôle de l’homme et de l’environnement, risques sanitaires
Jean-Pierre Carmouze, Marc Lucotte et Alain Boudou (dir.)
2001
Diasporas scientifiques
Comment les pays en développement peuvent-ils tirer parti de leurs chercheurs et de leurs ingénieurs expatriés ?
Rémi Barré, Valeria Hernández, Jean-Baptiste Meyer et al. (dir.)
2003
La dengue dans les départements français d’Amérique
Comment optimiser la lutte contre cette maladie ?
Raymond Corriveau, Bernard Philippon et André Yébakima (dir.)
2003
Agriculture biologique en Martinique
Quelles perspectives de développement ?
Martine François, Roland Moreau et Bertil Sylvander (dir.)
2005
Lutte contre le trachome en Afrique subsaharienne
Anne-Marie Moulin, Jeanne Orfila, Doulaye Sacko et al. (dir.)
2006
Les espèces envahissantes dans l’archipel néo-calédonien
Un risque environnemental et économique majeur
Marie-Laure Beauvais, Alain Coléno et Hervé Jourdan (dir.)
2006
Les ressources minérales profondes en Polynésie française / Deep-sea mineral resources in French Polynesia
Pierre-Yves Le Meur, Pierre Cochonat, Carine David et al. (dir.)
2016
Le développement du lac Tchad / Development of Lake Chad
Situation actuelle et futurs possibles / Current Situation and Possible Outcomes
Jacques Lemoalle et Géraud Magrin (dir.)
2014