Country study on burkina faso biodiversity conducted by the permanent secretariat of the national council for the management of the environment and the national



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CHAPIer 3 : current status of biological DIVERSITy in BURKINA FASO

In Burkina Faso, biological diversity has been the object of various human and climatic threats.


Man’s destructive action on biological diversity is mainly translated into bush fires, shifting cultivation, population pressure, overgrazing and overexploitation of biological resources. To these man-made factors must be added the effect of successive droughts since 1970. The combination of these two main factors leads to the degradation of biological diversity. The immediate consequences of these facts are the loss of biological diversity and the erosion of ecosystems. In Burkina Faso, the degradation of biological diversity is more perceptible in the north-Sudanese and Sahelian zones.

3.1 TAXONOMIC INVENTORY

The biological diversity of Burkina Faso is not well known in spite of the inventories made since the colonial period until today, because very few systematic inventories were made. However, the studies undertaken as part of the present monograph constitute pertinent references and bring out an appreciable biological richness. The total number of recorded species is 3 992 as far as macro-organisms are concerned, apart from micro-organisms for which few researches have been conducted. The following development deals with the summary situation of the knowledge on the taxonomy of the families, genera and species of the components of biological diversity. The details of this taxonomy are part of the document entitled “Annexe de la monographie nationale sur la diversité biologique du Burkina Faso” [Appendix of the Country Study on Biological Diversity in Burkina Faso].



3.1.1 animal kingdom (fauna)

The animal kingdom includes micro-organisms, aquatic and terrestrial insects, terrestrial, aquatic, wild and domestic vertebrates, and invertebrates.



3.1.1.1 micro-organisms

Micro-organisms are ubiquitous, i.e. they are present in almost all milieux, contrary to higher organisms whose distribution in the biosphere is more dependent on climatic zones (TRAORE A., 1997).


Burkina Faso, as a result of its geographical situation meets the minimal conditions in order to shelter most of the micro-organisms recorded in the world up to now. Indeed, according to  TRAORE A, 1997, many micro-organisms have been identified from samples of Burkina Faso soils or plants. Therefore, and for practical reasons, the documents under-describe the main groups of micro-organisms known today, even if their study has not been systematically undertaken in Burkina Faso. In the absence of their detailed description, the report lays emphasis on family and genera taxonomy.


3.1.1.1.1 Viruses

Viruses are parasites infecting insects, plants, vertebrates, invertebrates and bacteria. Often, their ultimate effect is the destruction of their host. Table 6 shows the inventory of viruses recorded in the world and which might be found in Burkina Faso.


Table 6: Family and genera number recorded according to virus categories.


Virus

Categories


Parasite viruses of vertebrates and others

Parasite viruses of plants

Parasite viruses of invertebrates

Parasite viruses of bacteria

Total

Family number

14

3

7

9

33

Genera number

31

22

19

12

84

Source : TRAORE A, 1997

3.1.1.1.2 Fungi and moulds

This group of micro-organisms includes fungi, yeasts and moulds. According to TRAORE A., 1997, there are 113 genera of fungi and moulds divided into 18 families.

3.1.1.1.3 Bacteria

Bacteria are metabolically very active despite their small size. They play a remarkable role in the bio-fertilisation, bio-energy and bio-protection reactions of the environment. For this reason, it is important to provide as detailed as possible taxonomic classification for them. On the basis of the structure of their wall or membrane, bacteria are classified into four main groups:




  • gracilicutes or gram-negative bacteria;

  • firmicutes or gram-positive bacteria;

  • tenericutes or bacteria without wall;

  • mendosicutes or bacteria with a very variable composition wall.

The summary of their taxonomic inventory is presented in the table below:


Table 7: Family and genera number according to recorded bacteria


Group of

bacteria

Gracilicutes or gram-negative bacteria

Firmicutes or gram-positive bacteria



Ternicutes or bacteria without wall


Mendosicutes or bacteria with a very variable composition wall

Total

Family number

54

14

3

12

83

Genera number

289

87

7

30

413

Source: TRAORE A., 1997


3.1.1.2 Insects

Insects comprise the largest numbers of species in the animal kingdom. However, the situation of knowledge in Burkina Faso of insect diversity is relatively weak as compared with their population. The entomological fauna of Burkina Faso is still not well known. For out of an estimate of 30 000 species, only 1515 species have been recorded in known documents of reference collections. Species of insects from some orders such as Hemenopterans have not yet been the object of an inventory (e.g.; bees, wasps). In addition, the geographical distribution of the various species has not yet been made.


The following taxonomic caption of Table 8 shows the quantitative situation of the knowledge of recognised entomological fauna in Burkina Faso.
Table 8: Quantitative situation of recognised entomological fauna in Burkina Faso


Identification

Orders

Families

Genera

Species

Quantity

22

151

250

1515

Source: OUEDRAOGO P, 1996, TRAORE C. A. et ZIGANI S. N., 1996.

3.1.1.3 Fauna

This sub-chapter deals purely with aquatic animals (except insects), those dependent on aquatic milieu (batrachians, reptiles, birds), terrestrial wild fauna and domestic fauna.



3.1.1.3.1 Aquatic fauna

The taxonomic inventories made on aquatic fauna results in the figures shown in table 9.


Table 9: Summary of the taxonomic situation of aquatic fauna


Taxons

Families

Genera

Species

Fishes

24

57

118

Batrachians

5

16

30

Molluscs

10

13

28

Crustaceans

5

7

6

Zooplanktons

10

13

16

Total

54

106

198

Source: TRAORE C. A. et ZIGANI S. N., 1996.

3.1.1.3.2 Terrestrial wild fauna

Vertebrate classes dealt with in this chapter are those of mammals, birds and reptiles. The situation of wild fauna is relatively well known, even if there is still much to do as far as field prospection is concerned. Table 10 shows the situation of the taxonomic knowledge of this fauna.



Table 10 : Summary of the taxonomic inventory of terrestrial wild fauna


Classes

Orders

Families

Genera

Species

Mammals

11

33

77

128

Birds

20

76

246

477

Reptiles

4

10

39

60

Total

35

119

362

665

Source: OUEDRAOGO L. et KAFANDO P., 1996

3.1.1.3.3 Domestic fauna

Domestic fauna is not abundant species because producers are seeking an important qualitative and quantitative yield of this fauna rather than variability. The taxonomic study of domestic fauna is summarised in the following table:


Table 11 : Summary of the taxonomic study on domestic fauna


Identification

Families

Genera

Species

Mammals

7

9

11

Birds

4

5

5

Total

11

14

16

Source : SANA O., 1997

3.1.2 plant kingdom (flora)

The flora is constituted of forestry, agricultural, food garden, industrial, medicinal, fodder, ornamental plants, etc. The study of the plant kingdom dealt with aquatic flora and terrestrial flora.



3.1.2.1 Aquatic flora

Very few inventories of Burkina Faso aquatic plants have been made. Indeed, of the country’s 1 300 water bodies, only 5 have benefited from a micro-flora taxonomic inventory, and hardly fifty have been studied from the viewpoint of herbaceous flora of aquatic milieux (OUEDRAOGO R. L., 1996).



3.1.2.1.1 Aquatic micro-flora

Taxonomic inventories of the aquatic flora at the level of n°2 and n°3 dams of Ouagadougou and Loumbila, Kompienga and Bagré dams gave the taxonomic results shown in table 12. In addition, the inventories undertaken show that, of this recorded micro-flora 22 have not been determined.


Table 12: Summary of the taxonomic study on aquatic micro-flora


Identification

Families

Genera

Species

Number

32

88

191

Source: OUEDRAOGO R. L., 1997.

3.1.2.1.2 Herbaceous aquatic macro-flora

Aquatic herbaceous flora is made up of herbaceous plants and includes four sub-groups:




  • aquatic macrophytes which are floating herbaceous plants

  • semi-aquatic macrophytes fixed at the bottom of water and whose upper part rests on the surface of the water;

  • macrophytes of water saturated zones;

  • hygrophile macrophytes living in dried out zones.


Table 13: Caption of the taxonomic inventory of aquatic herbaceous flora


Taxons-flora sub- groups

Families

Genera

Species

Aquatic macrophytes

23

28

46

Semi-aquatic macrophytes

20

36

69

Water zones saturated macrophytes

10

17

24

Hygrophile macrophytes

23

37

46

Total

76

118

185

Source : OUEDRAOGO R. L., 1996

3.1.2.2 Terrestrial flora

The taxonomic data collected on terrestrial flora concerned higher fungi, herbaceous flora, (herbaceous flora and agricultural herbaceous flora), ligneous flora (forestry, fruit, ornamental and medicinal).


3.1.2.2.1 Higher fungi

The taxonomic inventories of higher fungi in Burkina Faso are not as advanced as the ones of higher plants. According to SANOU and BA, 1996, 8 families, 13 genera and 28 species of higher fungi are now known in Burkina Faso.




3.1.2.2.2 Herbaceous plants

Although the floral inventories dealt with the whole country, knowledge on herbaceous plant taxonomy is not very important.


The taxonomic inventories made in all the areas of the country on terrestrial herbaceous plants made it possible to record 87 families, 333 genera and 627 species.
The data collected reveal the predominance of species from some families such as: leguminous plants (145 species) and graminae (145 species). Moreover, other families are considered as frequent in the field, particularly the Acanthaceae (26 species), Amaranthaceae (21 species), Asclepiadaceae (27 species), Convolvulaceae (27 species), Euphorbiaceae (12 species) and Solanaceae (12 species).

3.1.2.2.3 Ligneous forestry flora

Within the ligneous flora, the monogeneric families are more numerous than the multigeneric families which include the Caesalpiniaceae, Apocynaceae, Euphorbiaceae, Papilionaceae, Rubiaceae, Anacardiaceae, Ampelidaceae, Mimosaceae, Asclepiadaceae, Meliaceae, Palmae, Sapindaceae, Capparidaceae, Combretaceae and Sapotaceae. The local ligneous forestry flora (trees, small shrubs and creepers) includes 55 families, 214 genera and 376 species (with 95 exotic species).



3.1.3 Taxonomic summary of the inventory of species

Data shown in chapter 3.1 are summarised in table 14.


Table 14: Summary of biodiversity taxonomic inventories


Kingdom

Components

Number of

families

Number of genera

Number of species

s

Animalia

(Animals)



Insects

151

250

1515




Aquatic fauna

54

106

198




Wild fauna

119

362

665




Domestic fauna

11

14

16

Sub- total

335

732

2394

Plantae

(Plants)


Higher fungi

8

13

28




Algae

32

88

191




Aquatic herbaceous flora dependent on wetlands



76

118

185




Terrestrial herbaceous flora


87

333

627




Ligneous flora

55

214

376

Sub- total

258

766

1407

Grand total

593

1498

3801


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