Country study Burkina Faso
|Identification||Area (ha) %||Territory|
|Terrestrial ecosystems||25 140 000||91.22|
|Aquatic ecosystems||72 500||0.26|
|Total||25 583 500||93.84|
Source: OUADBA J. M., 1997
The rest of the country is covered with other types of environment, particularly dunes, towns, rocks, roads, etc. Some of these ecosystems or habitats have been the object of specific studies by technical services. They are:
Ecosystems maintain the lives of the other categories of biological diversity, including man. The richness of a country in biological diversity depends on the importance in quantity and quality of its ecosystems. The economy of Burkina Faso, as any agricultural country, depends on the functions of the ecosystems it shelters. Table 16 shows us a few examples of these functions, which benefit the development of Burkina Faso.
Table 16: List of a few functions of ecosystems.
|Function||Role played by ecosystems||Types of ecosystems or habitats|
|Production||Maintenance of fertility||Forestries, clogged wetlands|
|Maintenance of humidity||idem|
|Diversification of production||Agricultural zones, pastoral zones, pastures, zones which can be irrigated|
|Prevention of erosion / Protection||Slowing down of runoff water speed and winds||Ligneous and herbaceous forestry formations|
|Mildness of climate||Shade, increase in air humidity||Forestries, wetlands|
|Education||Availability of varied complexes||Terrestrial, aquatic|
|Scientific||Variation of ecological systems||idem|
|Aesthetic and recreational||Diversification of species||National parks|
Natural forestry formations are divided into protected areas (25%) and non-protected areas (75%). The domain of forest reserve covers a total area of 2,721,857 ha, i.e. 14% of the national territory.
Among the terrestrial ecosystems, forests account for an important position. The exploitation of the documentation produced under the aegis of the ministry in charge of environment reveal the following data concerning terrestrial plant formations. Plant formations (herbaceous and ligneous) cover 93% of the national territory distributed as follows: 60% of natural formation (forests, savannahs, steppes, spotted bushes), 32% of man-made formation (fallows and agroforestry parks, plantations). The detailed distribution of plant formations is shown in table 17, following the documents produced under the aegis of the ministry in charge of environment.
Table 17: Distribution of types of plant formations.
|Origins of formation||Types of formation||Area (ha)||% Territory|
|Natural||Gallery forests||270 000||1|
|Sparse forests||287 000||1|
|Bushy savannahs||4 291 000||16|
|Shrubby savannahs||10 185 000||37|
|Spotted tigers||387 000||1|
|Steppes||1 200 000||4|
|Man-made||Fallows and agroforestry parks||8 770 000||32|
|Total||25 410 000||92|
Source: OUADBA J. M., 1997.
The herbaceous cover presents characteristics related to the phytogeographical zone in which it is found. In general, the most representative families are in the decreasing order: gramineae (monocotyledones with hollow stem), leguminous plants (dicotyledones with pod), and cyperaceae (apetalous monocotyledones with full stem).
A recent study conducted by FONTES J. and GUINKO S., 1995, on plant formations in Burkina Faso, provides the distribution of plant formations according to domains and the country's phytogeographical sub-sector, as shown in table 18.
Table 18: Distribution of terrestrial plant formations according to phytogeographical zone
|Phytogeographical zones /Plant formations||Area (Km2)||% Territory|
|Grassy and bushy Steppe||8.619||3.18|
|Shrubby and bushy steppe||3.304||1.22|
|Shrubby to bushy steppe||7.237||2.67|
|Steppe and valley bush savannah||6.765||2.50|
|Bushy to wooded savannah||3.868||1.43|
|Bushy to shrubby savannah||75.965||28.05|
|Bushy savannah and Sourou grasslands-prone to floods||869||0.32|
|Shrubby and bushy savannah||33.412||12.34|
|Bushy to shrubby and wooded savannah||43.891||16.21|
|Bushy to wooded savannah and sparse forest||20.518||7.58|
|Forest-gallery and associated aquatic grassland||434||0.16|
Source: OUADBA J. M., 1997
According to the Ramsar Convention, "Wetlands are areas of swamps, marshy waste lands (peaty swamps), peat bogs or water (natural or artificial, perennial or intermittent) where the water is stagnant or running, fresh, briny (salty taste) or salted, including marine areas whose depth is not more than 6 metres deep during low tide".
Cowardin et al., in 1979, gave the following more globalising definition: "Wetlands are transition zones between terrestrial systems and aquatic systems where the water table is close to, or reaches soil surface, or where this surface is covered with shallow water."
In the Burkinabè context (a continental country), wetlands are formed by all the natural or artificial zones where water is running or stagnant, perennial or intermittent; they cover about 225 000 ha. Those are water reservoirs (dam lakes, depression lakes, and ponds), springs and flood basins. Appendix 3 shows the outstanding wetlands of Burkina Faso.
In the typology of Burkina Faso wetlands, there two categories : submerged wetlands and clogged wetlands.
a) Submerged wetlands
They include two categories:
In the category of zones submerged by running water, the size of streams depends on the catchment area. Thus, when the former is not more than a few hectares, we have brooks, ditches or torrents; for a catchment area of a few km² to thousands of km², we have a backwater; for rivers, the size of the catchment area is hardly more than 100 000 km².
At the level of running water, there are five main streams: Mouhoun, Nakambé, Nazinon, Comoé and Pendjari. Nakambé and its main affluents flow for an average of six months a year, Nazinon for six months; only Comoé and its affluent Léraba, Mouhoun and its affluent Kou and Pendjari have an perennial flow.
Bog water concerns lakes, ponds, water reservoirs and dams. The updated inventory of surface water resources estimates the number of water reservoirs to 1300 (OUEDRAOGO R. L., 1996). The perennity of natural and artificial water bodies highly depends on their respective depth and the climatic and physiographical zone of the country.
Zones submerged by bog water are those covered by perennial water. Among them, there are two big artificial water bodies, Kompienga (216 km2 with 2 billion m3 maximum) and Bagré (250 km2 with 1.7 billion m3), have a marked hydroelectric vocation. The ponds, including the Oursi Pond (Ramsar site), which used to be big and perennial are now subject to drainage; only the Hippopotamuses Pond (which is a biosphere reserve) is saved from this situation. Map n°10 shows the hydrographic network and the water reservoirs.
b) Clogged wetlands
Clogged wetlands are those with soils that are saturated by water. This saturation may be superficial and translated into a partial submersion hardly more than a few centimetres. It may be deep and translated into the existence of some hydrophile plant species or cultivated plants on the surface, requiring an hydric supply higher than can be provided by the regional climate.
Clogged wetlands are of two types: natural superficial clogging (related to the presence of streams, lakes and water reservoirs) and artificial clogging (irrigated areas).
The type of clogged wetland we are interested in here is natural superficial clogging. Depending on clogging, there are mouillere, bogs, marshes and swamps.
The mouilleres are temporarily clogged small areas, characterised by superficial drippings affecting locally the outcrop of an aquifer groundwater. Usually, mouilleres are found on the low sides at the margin of lowland central zones. They appear in mid-August and at the end of November in south and southwest zones of Burkina Faso.
Bogs are larger than mouilleres, and they are found in the central part of lowlands or at the margin of ponds and flood basins in the south-Sudanese zone.
In Burkina Faso, natural clogging of soils is intermittent because of the character of the climate.
|© 1999-2003, Clearing-House of Burkina Faso,
launched on the Internet the 16th of November 1999.
Contact person: M Soumayila Bance
Tel.: +226 - 50 324074-78
Fax: +226 - 50 31 64 91