The main pasture units
The Saharan domain
The sandy ergs. Psammophyllic vegetation is largely represented since the ergs occupy a non-negligible part of the national territory. They are characterised by a pseudo-steppe dominated by Stipagrostis pungens. The principal species associated with it are: Calligonum comosum, Cornulaca monocantha, Farsetia stylosa and Cyperus conglomeratus. The barkhans, practically bare of vegetation provide no grazing.
The stony regs are characterised by a very diffuse group dominated by: Acacia tortilis subsp. raddiana and Hammada scopania(Mint Soueidatt Fatimetou, 1988). Their main associate is Pergularia tomentosa.
The sandy regs: are characterised by a steppe of Aerva javanica and Fagonia oliveri. The grass stratum is dominated by Aristideae notably Aristida mutabilis.
The clayey-sandy regs: are characterised by a steppe of Nucularia perrini by far the most important formation; it is often accompanied by Salsola baryosma. The herb layer is dominated by Stipagrostis acutiflora. This pasture is greatly liked by camels.
The depressions and wadi beds: are vast expanses of reg the conformation of which allows the collection of the runoff after light rain. These environments harbour shrubby steppes formed by one or more of the following species: Acacia ehrenbergiana, Acacia tortilis, Maerua crassifolia, Balanites aegyptiaca, Capparis decidua, Boscia senegalensis, Calligonum comosum, Panicum turgidum and Cymbopogon schoenanthus.
The beaches and littoral dunes: carry a pasture with few pastoral resources composed of: Tamarix sp., Nitraria retusa, Atriplex halimus, Sporobolus spicatus, Polycarpea nivea, and Sesuvium portulacastrum.
Overall the productivity of these pastures is low.
The sub-desert Sahel.
On the red dunes with active crests, are found: Balanites aegyptiaca, Commiphora africana, Farsetia stylosa, Cyperus conglomeratus and Panicum turgidum. This pasture is much liked by the herders and remains in good state until the onset of the hot season.
In the calcareous inter-dune depressions are found: Maerua crassifolia, Capparis decidua, Leptadenia pyrotechnica, Fagonia oliveri, Panicum turgidum, Farsetia stylosa and Cyperus conglomeratus.
On the coastal dunes a steppe develops of Euphorbia balsamifera, Commiphora africana, Acacia tortilis, Panicum turgidum, Cenchrus biflorus and Tribulus terrestris. This formation has little value in the dry season
Shallow aeolian sands over sandstone are colonised by a pasture of difficult access of Euphorbia balsamifera, Boscia senegalensis, Aristida adscensionis and Tetrapogon cenchriformis.
On undulant regs with sand covered bottom land are found Boscia senegalensis, Capparis decidua, Panicum turgidum, and Farsetia stylosa. These regs have scattered loamy-clay depressions where most of the forage is found.
Overall the productivity of these pastures is very low, especially on sandy dunes, but is a bit better on sandy-loam peneplains.
The typical Sahel
On the fixed dunes we find: Balanites aegyptiaca, Acacia senegal, Leptadenia pyrotechnica, Cenchrus biflorus, and Alysicarpus ovalifolius. It is excellent grazing in the rainy season and the start of the dry season.
On sandy soils sometimes slightly loamy a pasture of good quality during the rainy season and the start of the dry season is found composed essentially of: Acacia senegal, Balanites aegyptiaca, Cenchrus biflorus, Aristida mutabilis and Heliotropium bacciferum.
In depressions between dunes with a sandy-loam substrate a herbaceous steppe develops in the rainy season of: Panicum turgidum, Aristida mutabilis, Cyperus conglomeratus, Euphorbia cordifolia, Farsetia stylosa, Aerva javanica, Fagonia oliveri, Pergularia tomentosa, Schoenefeldia gracilis, Aristida funiculata, Aristida mutabilis, Aristida adscensionis, and Cenchrus biflorus. The woody vegetation includes Boscia senegalensis, Maerua crassifolia, Balanites aegyptiaca etc.
The coastal dunes carry a steppe of Acacia tortilis, Salvadora persica, Commiphora africana, Chloris prieurii and Aristida mutabilis. In the inter-dunes are found Salvadora persica, Maytenus senegalensis, Borassus flabellifer, Cenchrus biflorus, Schoenefeldia gracilis and Aristida funiculata. This pasture can be used throughout the year.
In the low salty areas a steppe of sub-shrubs occurs: Arthrocnemum macrostachyum, Salsola baryosma, Salsola vermiculata, Zygophyllum fontanesii.
In the main beds of wadis with clay or sandy-clay substrates where runoff accumulates temporary pastures mainly based on annuals develop. The herb layer is composed of Panicum laetum, Cassia tora, Eragrostis tremulla, Pennisetum violaceum etc. The woody layer comprises Ziziphus mauritiana, Acacia ehrenbergiana, Acacia seyal etc.
On clay and clay-loam soils a luxuriant vegetation develops in the main beds of wadis dominated by Acacia scorpioides, Acacia seyal, Echinochloa colona and Aeschynomene indica. After overgrazing species of low palatability like Indigofera oblongifolia, Cassia tora, Spermacoce vermiculata proliferate while the plants liked by livestock like grasses and legumes tend to disappear.
The sterile Sahel regs with Acacia ehrenbergiana, Balanites aegyptiaca, Acacia senegal and Schoenefeldia gracilis are of little use and are mediocre in the dry season.
The Sahelo-Sudanian border
On fixed dunes a pasture develops of Balanites aegyptiaca, Acacia senegal, Aristida mutabilis, Cenchrus bifloris, Dactyloctenium aegyptium, and Sesamum alatum. It has a low carrying capacity, especially in the dry season.
On sandy soils sited at the base of plateaux are found: Combretum glutinosum, Acacia senegal, Sclerocarya birrea, Balanites aegyptiaca, Cenchrus bifloris, Aristida mutabilis, and Indigofera aspera. This is useful grazing throughout the year but with a reduced carrying capacity in the hot, dry season.
On sandy loams: Balanites aegyptiaca, Adansonia digitata, Combretum glutinosum, Aristida mutabilis, Eragrostis tremula, Indigofera senegalensis, Schoenefeldia gracilis and Zornia glochidiata. This is useful grazing throughout the year but with a reduced carrying capacity in the hot, dry season.
On regs with stony and gravelly soils we find Acacia seyal, Adansonia digitata, Schoenefeldia gracilis, and Aristida mutabilis. This pasture is of little importance in the dry season.
On the flanks of plateaux with stony soils with small wadis there is an extraordinary but inaccessible pasture composed essentially of Commiphora africana, Pterocarpus lucens, Combretum glutinosum, Blepharis linearifolius, Aristida adscensionis, Andropogon gayanus and Tetrapogon cenchriformis.
On clays and clay loams forests of Acacia seyal, Maytenus senegalensis, Andropogon gayanus, Pennisetum pedicellatum and Indigofera astragalina occur. This is an excellent dry season pasture.
The river valley.
On clay soils which are flooded by the Senegal river and its tributaries we find Acacia scorpioides, Acacia seyal, Faidherbia albida, Mimosa pigra, Ziziphus amphibia, Echinochloa colona, Aeschynomene indica, Sphenoclea zeylanica, Alternanthera nodiflora, Lotus glinoides, Chrozophora senegalensis, Ipomoea aquatica etc. Once the waters start to retreat (September) an uninterrupted band of cultivated fields develops for kilometres which makes the rich intercalated pastures inaccessible; these are later used by sedentary herds after harvest. This is an excellent dry season pasture. These pastures are far fewer in Mauritania than on the Senegal bank.
The coastal dunes carry very diverse woody vegetation containing, among others, Euphorbia balsamifera, Maytenus senegalensis, Tamarix sp., Nitraria retusa, Commiphora africana etc.
On coastal sands are found Ipomoea pes-caprae, Sesuvium portulacastrum, Alternanthera maritima, Cyperus maritimus etc.
Saline soil pastures
The delta of the Senegal river supports great areas, mostly inundated during floods, which carry often monospecific populations of one of the following: Typha australis, Phragmites sp., Cyperus sp., Sporobolus sp. and in addition Cressa cretica, Echinochloa colona, and Paspalum vaginatum. Here and there the flowers of Nymphea lotus can be seen. There are relic mangroves of Rhizophora sp. and Avicenna africana.
In the sebkhas where soils are very saline a population of Tamarix and-or Arthrocnemum macrostachyum is found
On the edges of flooded areas and on the periphery of sebkhas Arthrocnemum macrostachyum, Salsola baryosma, Salsola vermiculata Suaeda mollis, Cressa cretica etc. are found.
In saline depressions in the interior Nucularia perrini and Salsola baryosma are met with; this is excellent dry season grazing. Nevertheless it can only be tolerated by livestock for twenty days because of its salinity. Overall these pastures, greatly liked by camels, are of low productivity.
During the rains livestock energy and protein requirements are well met which explains the good condition of the herds and a satisfactory milk production. In the dry season the situation is reversed and all pastures provide forage deficient in both energy and protein, to such an extent that stock living off these pastures will become emaciated and may die (Boudet and Duverger, 1961).
Palatability of plants is a relative characteristic. The same species can be sought after or left alone according to the season, the age of the plants, the floristic composition of the pasture in which they are found and the species of grazing animal, (Annex 1, Ould Soulé A. 1995, 1998). Thus, following overgrazing, unpalatable or undesirable species proliferate. (UNESCO, 1961).
Forage resources are composed mainly by the shrub and tree layers. In fact during the dry season and particularly before the rains (the critical period) the green parts and fruits of woody vegetation provide the main if not the only source of protein essential to a balanced diet. The trees or shrubs which remain green throughout the year or are in leaf at the critical period (Combretum glutinosum, Balanites aegyptiaca, Faidherbia albida, Salvadora persica, Piliostigma reticulatum, Piliostigma rufescens, Indigofera oblongifolia etc.), the weedy lianas (Cocculus pendulus, Leptadenia hastata, Leptadenia arborea, Ephedra sp. etc.) and epiphytes like Tapinanthus spp. provide a nutritious contribution while the annual herbs only provide roughage of mediocre nutritive value. As for the perennial herbs (Panicum turgidum, Andropogon gayanus, Aristida pungens, Vetiveria nigritana etc.), they also provide quality feed.
The variable forage resources depend on the summer rains which are irregular and unreliable. The herbaceous pastures depend closely on the amount and distribution over time of the rainfall. Rain has to fall regularly, without big gaps, to allow herbs to complete their growth cycle from germination through flowering to seed maturity. The variable forage resources show the nature of the precipitation precisely. Scarcity, insufficiency and poor distribution limit forage production. The exploitation of pastures by herds of different compositions behaving in different ways vis á vis the forages: cattle graze the herbage to a certain height, sheep clip it to ground level whereas goats prefer to browse shrubs and camels feed on the leaves of trees and bushes, allowing a better valorisation of the grazing land.
Water resources, to which the grazing of the stock is closely tied, like the forage resources are also variable in time and discontinuous spatially. The permanent water sources are the Senegal river, the lakes Rhiz and Mâl and the deep water tables which feed the wells and bore-holes. These are the permanent element and the ultimate supply in the dry season. The variable water resources also depend on the summer rains; they are surface water (ponds, wadis etc.) and the shallow ground water recharged annually by infiltration of rain water and feed shallow wells which are often dry by the end of the dry season (May – June).
Where the stock graze is determined by the availability of mattoral forage and of water; in the rainy season these resources are generally satisfactory, in contrast in the dry season the grazing land is often limited by the lack of one or both of the two resources.
The installation of bores and wells in recent decades has brought about a profound modification in pastoral conditions. Herds stay longer on grazing areas, thus removing a quantity of vegetation largely exceeding the annual growth. Thus concentric rings are created around some boreholes and wells starting from a denuded area. The denudation of the soil is because of overgrazing and trampling and soil compaction.
Incomplete statistics indicate that 13,848,000 hectares of pasture produce 6.3 milliards of Fodder Units (UF) corresponding to 2,500,000 tropical livestock units (UBT) on the basis of 2,500 UF/UBT/year; now the national herd is 3,500,000 UBT which indicates that the carrying capacity of the pastoral ecosystem is largely exceeded. (Nations Unies, 2001). This calculation does not take account of the forage from trees and shrubs (aerial pastures). To avoid the destruction of that ecosystem, rational pasture management is necessary. That management should assure proper nutrition of the livestock while allowing both annual and perennial plants to regenerate.
Phytomass production on Mauritanian pastures is very dependant
on the weather; it varies from one wilaya to another according to the
rainfall and the area of the wilaya. From estimates of phytomass and calculations
of carrying capacity per wilaya it seems that the fodder balance is positive
overall with an excess of about 3.8 percent over the total needs of ruminants.
Nevertheless the balance is negative in six wilayas (Table 7). The Wilayas
of the two Hodhs, Assaba and Adrar produce three quarters of the national
In the north where conditions are difficult the agropastoralists who have understood well the need to provide a complementary feed (especially to goats) in lean periods cultivate fodder (mainly lucerne Medicago sativa) between the date palms. In contrast, in the south where conditions are better, fodder crops are still in an embryonic state in irrigated areas. Private and public trials have given encouraging results; several forages have been tried over many years. The most promising are: cowpea ISRA 66-35; Lablab purpureus or Dolichos lablab; Pigeon pea Cajanus cajan; lucerne Medicago sativa and fodder sorghum. Others have been tried: Clitoria ternatea, Macroptilium lathyroides, Crotalaria juncea, Pennisetum sp., Stylosanthes sp.
These forages are potentially usable for diversification of fodder crop production; most are from humid regions; so it is desirable to target zones analogous with our conditions. But why have local forages not been tested? Some of them produce forage of excellent quality. Stock rearers know well Blepharis linearifolius, Astragalus vogelii, Neurada procumbens, Crotalaria saharae, Tribulus terrestris, Opuntia sp. etc.
The main problems which livestock production faces in Mauritania concern, essentially, the management of pastoral resources. To contribute to an improvement of these resources, the following measures could be implemented.
The improvement of pasture resources must be through the rational management of these resources and herd mobility. In order to improve pasture management it would be necessary to set up an Observatoire Nationale des Ressources Pastorales which would be responsible for drawing up a consensual plan of pasture management which would favour the implementation of the Code Pastorale.
•Le Centre National de Recherches Agronomiques et
de Développement Agricole (CNRADA) :
•La Direction de la Recherche, de la Formation et
de la Vulgarisation (DRFV)
•Le Centre National d’Elevage et de Recherches
•L’Ecole National de Formation et de Vulgarisation
de Kaédi (ENFVA)
•La Direction de l’Environnement et de l’Aménagement
•La Direction de l’Agriculture (DA)
This profile was drafted by Ahmedou Ould Soule, lecturer and researcher at the Ecole Normale Supérieure de Nouakchott in March 2002 (and finalized in 2003), who will update it as necessary.
[Translation of the profile from the French original was done by J. M. Suttie and final editing was undertaken by J.M. Suttie and S.G. Reynolds in September 2003. Livestock data were updated in August 2006 by S.G. Reynolds.]