Country study Burkina Faso 
Biodiversity 

CHAPTER 2: A GENERAL SURVEY OF BURKINA FASO

2.1 HISTORY

According to the periodical edition of "ATLAS JEUNE AFRIQUE", 1993, the country was structured and organised before the French occupation that lasted from 1896 to 1960: a supreme chief the "Mogho-Naba", i.e. the Mossi king, ruled "The Mossi Empire of Ouagadougou". Called Upper-Volta (because located upstream of the big river "the Volta") after the arrival of the French, the country was divided between Mali, Niger and Côte d'Ivoire in 1932 and will not recover its autonomy and its borders until 1947. Upper-Volta became independent on August 5, 1960, and on August 4, 1984, the Republic of Upper-Volta was given the name "Burkina Faso", which means "the Land of Honest People".

2.2 GEOGRAPHIC SITUATION

Burkina Faso is a landlocked Sudanese and Sahelian country situated in the heart of West Africa. It is located between north of latitude 9°20' and 15°3', east of longitude 2°20' and west of longitude 5°3. With an area of 274 200 km2, the country is limited in the east by Niger, in the north and north-west by Mali, in the south by Ghana, in the south-west by Côte-d'Ivoire, in the south-east by Benin and Togo (Map 1)

Map 1: Geographical situation of Burkina Faso

2.3 ADMINISTRATIVE DIVISIONS

In 1996, Burkina Faso was divided into 45 provinces, each under the leadership of one (1) Haut Commissaire (highest ranking political and administrative official of the province). The data of the present study were collected from the former administrative division, which included a total of 30 provinces. The provinces are divided into districts under the authority of prefects. Districts are sub-divided into villages led by Traditional Chiefs. The whole country has a total of 355 districts and 8 500 villages. Maps 2 and 3 respectively show the old and new division of the country into provinces.

Map 2 : Division of Burkina Faso into 30 provinces

Map 3 : Administrative division of Burkina Faso into 45 provinces

2.4 PHYSICAL ENVIRONMENT

2.4.1 CLIMATE

In general, Burkina Faso is characterised by a tropical climate of the Sudanese and Sahelian type, with two alternating seasons: a long dry season from October to April and a short rainy season from May to September. The majority of the country is situated in the climatic zone of Sudanese type, particularly the centre and the south, whereas the extreme south and the south-west are part of the Sudanese and Guinean zone. The northern part is under the influence of the Sahelian climate.

A study of climatological records covering the period from 1961-1990 (see Atlas Jeune Afrique, 1993, and Atlas Agro-climatologique des pays de la zone du CILLS) revealed that in Burkina Faso:

• temperatures are always higher than zero degree °C, no matter the time of the year;
• monthly average temperatures rarely go beyond 35 °C ;
• variations in thermal amplitude are more pronounced in the north than in the south of the country;
• the relative humidity of air is low with a high evaporative demand in the dry season which may be more than 10 mm of water a day;
• rainfall varies from 300 mm in the extreme north to 1100 mm in the extreme south and south-west;
• the rainy season begins sporadically as early as April in the south before covering all the country in June;
• the end of the rainy season occurs quickly by the end of September in the north and by the end of October in the south.

In comparison with the period from 1951 to 1960, one notices a clear decline in the average of rainwater quantities for the period 1961-1990, which falls from 400 mm to 300 mm in the north and from 1300 mm to 1100 mm in the south. Map 4 shows the present isohyets for all the country.

Map 4: Average rainfalls (period 1960-1986)

2.4.2 RELIEF

The majority (about 75%) of the Burkinabè territory rests on Precambrian crystalline platform turning the overall relief flat. The average altitude is 400 m, while the highest altitudes range between 125 m in the south-east (Pama region) and 749 m in the south-west (Ténakourou Peak). Two main topographic domains cover the territory of the country: a large peneplain covering 3/4 of the country and a sandy massif in the south. Besides these two domains, one can notice a few specific forms of relief such as dunes, chains of hills and/or small mountains, crusted tables and a few cliffs.

2.4.3 SURFACE GEOLOGY

The main geological data collected in Burkina Faso are follows:

• the existence of a granito-gneissic platform dating from the Precambrian age which covers the majority of the country (particularly the centre and east);
• the existence of sandstone massif rich in aquifers in the west towards Mali;
• the presence of fossil sandy bars in the Sahelian region oriented from east to west;
• the presence in the Central Plateau of a Birrimian arch characterised by green rocks constituting a series of more or less pronounced reliefs breaking away from the overall monotony of the landscape.

2.4.4 HYDROGRAPHY

The country's surface water resources are estimated at 10 billion m3 per year, while ground water resources are evaluated at more than 6 billion m3 per year (OUEDRAOGO N. A., 1996).

The hydrographic network, which drains all the waters, includes three big international basins of uneven importance bearing the names of the main streams draining them (Map 5). These are :

• the Volta basin : it covers an area of 178 000 km², fed by the Mouhoun, Nakambé and Nazinon rivers, formerly called respectively Volta Noire, Volta Blanche and Volta Rouge, and covers the central part of the country;
• the Comoé basin : with an area of 1 700 km² is fed by the Comoé river and its affluents, the Léraba and Yanon and covers the south-west of the country;
• the Niger basin: with a total of 79 000 km² is fed by the affluents of River Niger in the east by the Bali, Garouol, Sirba, Gouroubi, Diamangou and the Tapoa, and in the west by the Banifing.

In general, most of the streams have a seasonal flow. There are only three perennial streams but non-navigable all year. They are: the Mouhoun, the Comoé, and the Pendjari. The following streams have a seasonal or intermittent flow: the Nazinon, the Nakambé and the Sirba. Perennial water bodies include natural lakes (Bam and Dem), the Hippopotamuses Pond, the Oursi Pond, and artificial lakes of which two, Kompienga and Bagré, are big water bodies with a marked hydroelectric vocation.

Map 5: International catchment areas

2.4.5 PHYTOGEOGRAPHY

The phytogeographic domains take into account the vegetation and flora of the region concerned. In general, they correspond to the distribution areas of the main physiognomic types of vegetation (biomes or plant formations) recognised, as well as to the distribution areas of the main floral groups which characterise them in families or taxons (OUADBA J. M., 1997).

The main current phytogeographic features of Burkina Faso are:

• the Sahelian domain : it is arid and covers the northern part of the country with a rainfall < 600 mm;
• the Sudanese domain: it is less arid and covers the rest of the country and receives a rainfall >700 mm.

In detail, one distinguishes from north to south a sub-Sahelian transition zone, a north-Sudanese zone and a south-Sudanese zone. The phytogeographic zones are divided into sectors and districts. (Map 6).

Map 6: Phytogeographic territories

2.4.6 VEGETATION

The natural vegetation of Burkina Faso has been the object of many studies. The studies by GUINKO S. (1984) "Végétation de Haute-Volta" represent a reliable reference. Recently, CNSF studies on the ecological units of the vegetation have provided further useful precisions. Finally, the most recent studies dealing with vegetation cartography and land use in Burkina Faso (FONTES J., DIALLO A., COMPAORE J. A., 1995) constitute an up-to-date source of information, which is useful for the development of the country study on biological diversity (GEOCONSEIL, 1996). Map 7 shows the natural vegetation.

2.4.6.1 Vegetation of the Sahelian domain

On the whole, it is a grassy, bushy, shrubby and thicket steppe usually quite sparse. Ligneous species may come together locally to form more or less penetrable bushes.

In the north of the fourteenth parallel, the north Sahelian sector stands out alone characterised by a batch of Saharan and Sahelian species which are found very rarely in the sectors further south. Among others, one can cite: Acacia ehrenbergiana, Acacia nilotica variety tomentosa, Acacia raddiana, Grewia tenax, Leptadenia pyrotechnica, Maerua crassifolia, Salvadora persica, for the ligneous species. This steppe includes thin riparian bars predominated by Anogeissus leiocarpus, Mitragyna inermis, Acacia ataxacantha and Acacia seya dominentl.

The south Sahelian sector covers the thirteenth and fourteenth parallels. The Saharan and Sahelian based flora species enriches itself with Sudanese components. The vegetation physiognomy is always the steppe type, even if the thirteenth parallel clearly demarcates the extension limit of savannahs north. The most common ligneous species of this sector are: Acacia laeta, Acacia nilotica adansonii variety, Acacia senegal, Boscia salicifolia, Commiphora africana, Dalbergia melanoxylon, Pterocarpus lucens and Grewia flavescens. The following Sudanese and very ubiquitous species are quite well represented in this sector: Acacia macrostachya, Combretum glutinosum, Combretum nigricans elliotii variety. They particularly form the composition of the bushes or "spotted bushes" associated with Pterocarpus lucens and Dalbergia melanoxylon.

2.4.6.2 Vegetation of the Sudanese domain

It develops south of the thirteenth parallel. The Sudanese savannahs gradually take over the steppe formations. At the same time that the herbaceous ground cover fills out higher the ligneous species increase. From north to south, global improvement axis of hydric conditions, the physiognomy of the savannah can become in succession herbaceous, shrubby, bushy and thicket to tend eventually towards a clear forest in the extreme south-west. The densification of the herbaceous plant material favours the annual passage of fires considered as a powerful factor for the maintenance of such a formation.

Between the thirteenth and fourteenth parallels the Sudanese-north sector stands out alone. It is a very highly populated sector and the savannah shows a regular rustic landscape of park type, predominated by big trees belonging to the protected agro-forestry species such as: Acacia albida, Adansonia digitata, Butyrospermum paradoxum subsp. parkii, Lannea microcarpa and Tamarindus indica.

In the grassy stratum, the share of perennial species intensifies. In the ligneous stratum, one always notices a more important shrubby stratum where combretaceae are well represented. The most regular species are: Acacia dudgeoni, Acacia gourmaensis, Acacia seyal, Bombax costatum, Combretum micranthum, Combretum glutinosum, Combretum nigricans, Grewia bicolore, Guiera senegalensis and Sterculia setigera.

Despite their small extent, it is important to note the presence of dry pockets of dense forests constituting "sacred woods". These woods represent vestiges of ancient forest climates saved from clearing because they were protected by customary practices. They are predominated by Anogeissus leiocarpus, Diospyros mespilifomis, Celtis integrifolia, Acacia pennata and Pterocarpus erinaceus.

The Sudanese-south experiences the less xeric climates of Burkina Faso. It includes the densest forestry formations. GUINKO S (1984) subdivided this sector into (4) districts where a common Sudanese floral deposit is found and which are associated with Guinean riparian species such as Cola laurifolia, Manilkara multinervis, Elaeis guineensis, Dialium guineense and Antiaris africana. It is agreed to define this sector as that of Isoberlinia doka, a cesalpiniaceae characteristic of Sudanese and Guinean savannahs. A succession of ligneous, wooded or shrubby species can be associated with it. Let us cite: Acacia polyacantha subsp. campylacantha, Acacia sieberiana, Anogeissus leiocarpus, Burkea africana, Daniellia oliveri, Khaya senegalensis, Parkia biglobosa. To this non-exhaustive list must be added more Guinean species often associated with the hydrographic network.: Carapa procera, Chlorophora excelsa, Monodora tenuifolia, Voacanga africana. Map 7 shows all the types of vegetation of Burkina Faso.

Map 7: Types of vegetation (according to Fontes, Diallo et Compaoré, 1995 )

2.4.7 SOILS

The soils of Burkina have been the object of many studies. But, ORSTOM and BUNASOL particularly conducted the greatest number. Thus, the entire territory of Burkina Faso was covered to 1/1500,000. These documents are important and they constitute the basis of most researches in pedology in the country today.

In a nutshell, it can be said that the national territory is covered by soils with a relatively poor level of fertility, particularly in phosphorous and nitrogen, and a limited water reserve. They suffer very acutely from the phenomenon of runoff and from hydric and wind erosion.

Pedological studies undertaken in Burkina Faso mention nine main types of soils which are as follows: raw mineral soils, hardly developed soils, vertisols, isohumic soils, brown soils, ferrallitic soils, soils with iron and manganese sesquioxyde, hydromorphic soils and sodium soils or salsodium soils. The main types of soils encountered in Burkina Faso are presented in table 1.

Table 1 : Types and characteristics of soils

2.4.8 ROAD INFRASTRUCTURES

Burkina Faso now owns a road network of 12 506 km of which 726 are tarred. Table 2 below presents the situation of road infrastructures classified according to category and region.

Table 2: Road infrastructures classified according to category and region

Classified region	Category of roads in km
	National	Regional	District	Unclassified	Total
Ouagadougou	912.8	135	361.9	101.9	1 511.6
Bobo-Dioulasso	864	429	632	123	2 048
Ouahigouya	600.4	428.2	75.2	112	1 215.8
Fada N'Gourma	694.8	216	424	170	1 504.8
Dédougou	660.4	306	770.1	None	1 736.5
Dori	104.6	513.2	226	None	843.8
Léo	361.4	313.6	130.1	80.4	885.5
Gaoua	512	58	325	315	1 210
Kaya	418.2	292.6	42.5	None	753.3
Tenkodogo	481.5	290.1	25	None	796.6
Total	5 610.1	2 982	3 011.8	902.3	12 506

Map 8 Communications