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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3.2.3.1 Presentation of the richest habitats in fauna and flora diversity

In Burkina Faso, like everywhere in the world, biological diversity is distributed through all the country’s ecosystems according to the biology and ecology of each species. Today, these ecosystems are victims of many natural and man-made factors, particularly, persistent droughts and population pressure, which make their equilibrium precarious. The consequence of this is the reduction of species ecosystems and habitats, the scarcity of some species, which have now become fragile, the change in attitude of some species, etc.


Today, the richest (qualitatively and quantitatively) habitats in species amount to the various conservation areas of terrestrial fauna (national parks, synergetic zones, biosphere reserves, etc.), protected forests, natural and artificial wetlands (ponds, dam lakes, developed areas, etc.). In these agricultural zones, there is an increasing development of a vertebrate fauna dependent on these types of habitats (eg. : crop destructive insects).

3.2.3.1.1 National parks, natural reserves and other protected zones

In the report, presented by Burkina Faso at the United Nations Conference, on the Environment and Development held in Rio de Janeiro, Brazil, in1992, the country’s natural forestry formations are divided into two domains: the non-protected domain (11 604 000 ha, i.e. 75% of formations) and the protected domain (3 816 000 ha, i.e. 25% of formations). The protected formations (protected forests and the silvi-pastoral and partial fauna reserve) are 65 and cover a total area of 2 678 747 ha (source : GUINKO S., 1996). The development below presents the components of the protected domain.


a) National parks.
They include the total protection zones of wildlife and its habitat where the only samples allowed are those of improvements by technical services, (by involving resident populations). There are two (2) in the country, particularly the “W” National Park, established by decree on August 14 1954 with an area of 350 000 ha, situated in the Tapoa province, half-way between Niger, Benin and Burkina Faso, and the Kaboré Tambi National Park in Pô, Nahouri province, established by order 76-02/PRES-ET of 02/09/1976. The total area of national parks is 390 500 ha, i.e. 10% of protected formations.
b) Wildlife reserves.
Wildlife reserves are protected natural zones or wildlife exploitation (sampling, hunting, and tourism of vision, etc.) is regulated.
Burkinabè wildlife, which used to be very rich has now become much poorer today. The existing big wildlife is mainly concentrated in the extreme south of the protected zones of the southwest zones (Comoé province), Centre-south and southeast (provinces of Sissili, Nahouri, Gourma and Tapoa). The Arly wildlife reserve and the Nazinga game ranch are high observation points of big wildlife (source: Notice de la Carte de végétation du Burkina Faso, GUINKO S. et FONTES J., 1995).

Wildlife reserves cover 2 545 500 ha. The are nine (9) most important ones in terms of area and they are subdivided into two categories according to the management approach applied to them. Thus, four total reserves and five partial reserves can be distinguished; the list of the 9 wildlife reserves is shown in table 19.


Table 19: List of wildlife reserves



Name

Classification

Area (ha)

Year of

establishment


Situation

Arly Wildlife Reserve

Madjoari Wildlife Reserve

Singou Wildlife Reserve

Bontioli Wildlife Reserve

Arly Wildlife Reserve

Kourtiagou Wildlife Reserve

Pama Wildlife Reserve

Nabéré Wildlife Reserve

Bontioli Wildlife Reserve
TOTAL


Total

Total


Total

Total


Partial

Partial


Partial

Partial


Partial

76 000

17 000


192 000

12 700


96 000

51 000


223 700

36 000


29 500
733 900

1954

1970


1955

1957


1954

1957


1955

1957


1957

Tapoa province

Tapoa province

Gourma province

Bougouriba province

Gourma province

Tapoa province

Gourma province

Bougouriba province



Bougouriba province


Source: OUEDRAOGO N. A., 1997.
The areas mentioned for the various reserve categories are the ones existing in official records. However, the actual areas are less than these figures because of the various pressures mentioned earlier. In addition to these reserves, there is the Nazinga Game Ranch, which contains an important diversity of vertebrates.
c) The silvi-pastoral and partial wildlife reserve
In Burkina Faso, there is a silvi-pastoral and partial wildlife reserve known as of the Sahel, which covers an area of 1 600 000 ha, corresponding to the Soum, Séno and Oudalan provinces. It is a zone where pastoral activities are undertaken in natural pastures and where there is a wildlife reserve open to pastoral activities. The main part of this reserve is now subject to exploitation systems which do not conform with the status of a reserve; this explains why the prospecting undertaken as part of the UPV-82/008 project retained a zone of 1 220 km2 comprising the west of Forage Christine, the Oursi and Béli ponds for the conservation of the representative ecosystems of Burkinabè Sahel (source : OUEDRAOGO N. A., 1997).
d) Synergetic reserves
They concern the wildlife-protected areas where hunting is controlled and wildlife habitat partially protected. Depending on their management systems, they are either real synergetic zones, controlled by the State agencies in charge of environment, or zones hired by the State to individuals who ensure their management themselves following laid down specifications.
e) Reserves of international importance
Three protected domains in Burkina Faso have an international importance, i.e. belonging to world patrimony. These are : The Hippopotamuses Pond (biosphere reserve of an area of 19 200 ha) situated in the Houet province, the Oursi Pond (Ramsar site with an area of 45 000 ha) in the Oudalan province , and the “W” Park (Ramsar site with 235 000 ha), half-way between Burkina Faso, Benin and Niger.
f) Protected forests
According to METRO A., 1975 protected forests are the forestry zones defined and demarcated as such according to a legislative and regulatory measure, in such a way as to give it the required legal protection. The protected forests of Burkina Faso cover a total area of 1 112 747 ha, without the Sahel silvi-pastoral and partial wildlife reserve (see. Table 20). However, this total area is theoretical, because of the illegal settlements forests are subjected to.
Table 20: Situation of protected formations in Burkina Faso


Province

Name of the formation

Situation

(district, village)

Date

Of designation classification

N° of order -

decree- of designation

Area

(ha)

Comoé

FC Bérégadougou

Banfora

4 Nov. 1953

8107 /SE / F

5 000

Comoé

FC Bounouna

Sidéradougou

31 May 1955

4088 /SE / F

1 300

Comoé

FC Boulon

Sidéradougou

31 May 1955

4087 /SE / F

12 000

Comoé

FC Kongoko

Sidéradougou

31 May1955

4089 /SE / F

27 000

Comoé

FC Kaflandé

Banfora

4 Nov. 1953

8106 /SE / F

30 000

Comoé

FC Diéfoula

Niangoloko

29 Nov. 1937

3499 /SE / F

85 000

Comoé

FC Logoniégué

Mangodara

4 August 1955

689 / FOR

29 000

Comoé

FC Babolo

Niangoloko

22 Sept. 1943

3413 /SE / F

550

Comoé

FC Gouandougou

Sidéradougou

31 May 1955

4086 /SE / F

9 500

Comoé

FC Dida

Mangodara

4 August 1955

688 / FOR

75 000

Comoé

FC Toumousséni

Banfora

12 April 1954

2875 /SE / F

2 500

Comoé

FC Yendéré

Niangoloko

5 April 1934

1312 /SE / F

700

Comoé

FC Source du Mouhoun

Moussodougou

31 May 1955

4084 /SE / F

100

Comoé

FC Niangoloko

Niangoloko

27 Feb. 1936

420 /SE / G

6 654

Boulgou

FC Ouilingoré

Zabré

23 Oct. 1936

2500 / SE

6 850

Boulgou

FC Yakala

Tenkodogo

23 Oct. 1936

2500 / SE

1 600

Bougouriba

FC Dibon

Diébougou

24 June 1954

4637 / SE/F

20 000

Bougouriba

FC Bougouriba

Diébougou

4 August 1955

690 / FOR

8 500

Bougouriba

FC Bontioli

Diébougou

23 March 1957

3147 / SE/F

29 500

Bougouriba

FC Nabéré

Diébougou

3 August 1953

5768/ SE/ EF

36 500

Houet

FCMaro

Houndé

28 Jan. 1940

116 / SE

50 000

Houet

FC Bahon

Houndé

26 March 1937

836 / SE

1 600

Houet

FC Tui

Houndé

17 Jan. 1940

115 / SE

50 000

Houet

FC Dindéresso

Bobo-Dsso

27 Feb. 1936

26 August 1941



422 / SE ou

3006 / SE / E



8 500

Houet

FC Mare aux Hippopotames

Satiri

26 March 1937

836 / SE

19 200

Houet

FC Koulima

Bobo-Dsso

27 Feb. 1936

421 / SE or

1486 / SE



2 150

Houet

FC Bansié

Bobo-Dsso

26 March 1937

836 / SE

300

Houet

FC Mou

Bobo-Dsso

20 Oct. 1938

3406 / SE

34 000

Houet

FC Dan

Bobo-Dsso

3 August 1953

5765 / SE

4 300

Houet

FC Téré

Kouka

23 Nov. 1951

8314 / SE/ F

10 700

Houet

FC Kou

Bobo-Dsso

13 Jan. 1951

190 IGF

117

Houet

FC Péni

Bobo-Dsso

24 Sept. 1942

3389 / SE/ F

1 200

Houet

FC Koa

Bobo-Dsso

27 April 1936

891 / SE

350

Houet

FC Bambou

Bobo-Dsso

26 March 1937

836 / SE

1 800

Houet

FC Kapo

Houndé

26 March 1937

836 / SE

9 900

Ganzourgou

FC Wayen

Wayen

26 August 1941

3009/SEor3005

12 000

Kadiogo

FC Barrage

Ouagadougou

9 Oct. 1936

26 August 1941



2376 / SE

3004 / SE



260


Table 20 (continued)


Province

Name of the formation

Situation (district, village)

Year of designation

N° of order / decree / of designation

Area(ha)

Kouritenga

FC Sitenga

Koupéla

23 Oct. 1936

2500 / SE

840

Mouhoun

FC Pâ

Boromo

19 June 1937

1639/SE/S

15 625

Mouhoun

FC Bonou

Boromo

19 June 1937

1639/SE/S

1 700

Mouhoun

FC Tuy

Bondokuy

17 Jan. 1940

115/SF/5

50 000

Mouhoun

FC Nasébou

Boromo

19 June 1937

117/SE

14 000

Mouhoun

FC Sâ

Dédougou

17 Jan. 1940

3320/SE

5 400

Mouhoun

FC Kari

Dédougou

13 Oct. 1938

3320/SE

13 000

Mouhoun

FC Ouoro

Dédougou

13 Oct. 1938

3320/SE

14 000

Mouhoun

FC Toroba

Dédougou

13 Oct. 1938

3320/SE

2 700

Mouhoun

FC Tissé

Dédougou

13 Oct. 1938

3320/SE

21 500

Mouhoun

FC Sorobouty

Boromo

13 Oct. 1938

17 Jan. 1940



113/SF/S

5 800

Mouhoun

FC 2 Ballé

Boromo

19 June 1937

1639/SE/S

115 000

Nahouri

FC Pic de Nahouri



13 Oct. 1938

3320/SE/S

836

Nahouri

FC de Nazinga



4 Decem. 1953

8827/SE/F

38 300

Namentenga

FC Tougouri




9 Oct. 1936

2376/SE

40

Oubritenga

FC Nakambé

Ziniaré, Manga, Kombissiri

3 August 1953

5767/SE/EF

98 000

Oubritenga

FC Ziga

Ziniaré

3 August 1953

5769/SE/EF

9 000

Oubritenga

FC Gonsé

Saaba

28 Feb. 1953

1550/SE

6 000

Oubritenga

FC Bissiga

Zitenga

23 Oct. 1936

26 August 1941



2500/SE

3003/SE


4 100

Passoré

FC Niouma

Yako

12 April 1954

2878/EF

735

Passoré

FC Twéssé

Yako

24 June 1954

4638/SE/F

490

Poni

FC Koulbi

Batié

4 August 1955

387/FOR

40 000

Sanmatenga

FC Yabo

Kaya

9 Oct. 1936

2376/SE/S

1 000

Sanmatenga

FC Dem

Kaya

19 June 1937

1639/SE/S

350

Sanmatenga

FC Nakambé




9 Oct. 1936

2376/SE

2 000

Sanguié

FC Kalio

Pouni

17 Janv. 1940

May 1 1936



111/SE/S

961/SE


12 000

Sissili

FC Sissili

Léo

31 Decem. 1955

1093/FOR

32 700

Soum-Séno-Oudalan

Réserve sylvo-pastorale et partielle de faune du Sahel

Séno-Oudalan-Soum

9 Decem. 1970

Ordonnance n° 70/302/PRES/AGRI-EL

1 600 000

Sourou

FC Sourou

Yaba

27 March 1937

1092

14 000

TOTAUX

66










2 712 747

Source: GUINKO S., 1996


3.2.3.1.2 The situation of protected areas

In addition to the late initiation of the measures in order to protect them (1936-1957), the protected zones are increasingly faced with an accelerated degradation which constitutes a serious threat. The main damages protected formations are subjected are:




  • degazetting, modifications of demarcations and changes in the status of some forests;

  • every 1/3 of the country’s area undergoes bush fires;

  • clearing of almost 100 000 ha/year of forestry lands;

  • fragilisation of ecosystems by their inappropriate exploitation;

  • resurgence of the degradation of formations because of population and livestock, as well as the successive droughts which cause a plant and animal massive death.

Inside protected areas all the components of biological diversity do not benefit from practical appropriate conservation measures. This is particularly the case of entomological fauna and aquatic flora, which represent hardly explored domains. In addition, efforts made as part of conservation and sustainable use of biological diversity are characterised by constraints coming mainly from the poverty of the populations often struggling for their survival.


3.2.3.2 Richness in species of ecosystems

In general, the diversity of species in the Burkina Faso ecosystems is not well known. The presentation, in chapter 3.1, as well as the summary in table 14 illustrate this situation. Indeed, the various thematic reports developed for the present report underscored this weakness, and this is why the data has not been established for all the taxonomic groups.



3.2.3.3 Endangered species

Endangered species in Burkina Faso are determined through legislative texts specifying the condition of their protection. The list of extinguished, threatened and vulnerable species is not well stocked because of the recent character of the particular attention paid to the various constituent components of the country’s global biodiversity. Table 21 below gives the list of such species.


Table 21: Situation of extinguished, dying, threatened and vulnerable species at the national level.


Category

Extinct

About extinction

Threatened

Vulnerable

Total

Mammals

Oryx




Panther

Cheetah


Elephant

Damaliscs

Gazella Rufifron

Gazella Dorcas

Wild dog


8

Birds




Ostrich

Abyssian hornbill

West African crowned crane

3

Reptiles







Crocodile

Python





2

Fishes










Protopterian (eel)

1

Ligneous flora




Celtis integrifolia

Adenium obesum

Acacia senegal

Dalbergia melanoxylon

Pterocarpus lucens

Vitex doniana

Ximenia americana


Adansonia digitata

Bombax costatum

Ceiba pentandra

Anogeissus leiocarpus

Khaya senegalensis

Prosopis africana

Parkia biglobosa

Butyrospermum paradoxum


15


Table 22: Endangered plant species in the north and centre-north of Burkina Faso.


Overexploited species now scare around urban centres

Scarce species about extinction

Vulnerable food species

Daniella oliveri

Acacia erythrocalix

Adansonia digitata

Diospyros mespiliformis

Annona senegalensis

Bombax costatum

Entada africana

Brachystelma simplex subsp. banforae

Butyrospermum paradoxum subsp. parkii

Fagara xanthoxyloides

Gossypium anomalium

Detarium microcarpum

Nauclea latifolia

Guibourtia copallifera

Lannea microcarpa

Rauvolfia vomitora

Hibiscus gourmassia

Sclerocarya birrea.

Securidaca longepedunculata

Landolphia heudolotti

Spondias mombin

Trichilia roka (= T. emetica)




Saba senegalensis variété glabriflora

Vitex doniana




Parkia biglobosa

Ximenia americana




Tamarindus indica

Source: BÉLEM B., 1996, et BOGNOUNOU O., 1997.


3.2.3.4 Endemism 

The situation of endemism is very little known in Burkina Faso. However, there is a timid knowledge concerning flora for which it has been established that, at least, 23 existing species in Burkina Faso are endemic in West Africa. Table 23 lists these species and their respective families.




Table 23: West African scarce/or endemic species




Family

Genus and species

1

Mimosaceae

Acacia erythrocalyx

2

Scrophuliaceae

Craterostigma plantagium

3

Fabaceae

Aeschynomene mbacoundensis

4

Limnocharitaceae

Lagarosiphon muscoides

5

Malvaceae

Gossypium anomalum

6

Rubiaceae

Botopedima tenius *

7

Cyperaceae

Afrotrilepis pilosa

8

Cyperaceae

Bulboschoenus maritimus

9

Cyperaceae

Eleocharis decoriglumis

10

Cyperaceae

Schoenoplectus articulatus

11

Cyperaceae

Cyperus articulatus *

12

Fabaceae

Sesbania rostrata

13

Alismataceae

Sagittaria oblusifilium

14

Caryophyllaceae

Polycarpaea dillei

15

Poaceae

Eragrostris lingulata

16

Malvaceae

Hibiscus gourmania

17

Hamarylliaceae

Crinum mulicum

18

Oleaceae

Jasminum kerstingii (very localised)

19

Poaceae

Rytachne furtira

20

Poaceae

Elionurus euchaetus

21

Aslepiadaceae

Gongronema obscurum

22

Asclepiadaceae

Brachystelma simplex, subsp. anforae

23

Caesalpinaceae

Guibourtia copallifera**


According to LEBRUN, 1991 et OUEDRAOGO, 1994.

Key : *= present in the Sindou Peaks

**= present in Tourny (Kankalaba)

3.2.3.5 Introduced Fauna and Flora species and varieties

The introduction of species in a country constitutes a means to mitigate a loss at the economic, sociocultural and scientific level. In Burkina Faso where the increase in production and the fight against the consequences of drought represent priorities, the recourse to exotic species is a common practice. The activity sub-sectors which introduce species and varieties are particularly agriculture and forestry. Thus, for example, of 320 species of domesticated ligneous flora, 201 are exotic (BELEM B., 1996). In addition, the livestock sub-sector has recourse to the introduction of varieties of animal species.

The main types of plants being introduced are ligneous plants, food crops, market garden crops, industrial crops, cash crops and decorative plants.

As far as domestic wildlife is concerned, the following breeds have been introduced:




  • at the level of cattle the Azawak zebus and M’Bororo zebus (Niger), the Gouadalis (Nigeria), and the N’Dama Taurus (Côte d’Ivoire);

  • at the level of sheep, the bali-bali breed (Macina);

  • at the level of pigs, breeds such as the Korogho pig (Côte d’Ivoire);

  • at the level of poultry, the Gallor guinea-fowl, Rode-Island Red hens, the Plymouth, the Nera (Europe).



3.2.3.6 Domestic animals and cultivated plants

Domestic animals and cultivated species rank high in the uses of the constituent components of biological diversity in Burkina Faso, because the country has an agro-pastoral vocation.



3.2.3.6.1 Domestic animals

Domestic fauna experienced more and more a phenomenon of crossbreeding, because of the search for bigger sizes and yield. The few traditional farmsteads of the country are more and more abandoned in favour of the raising of species that have bigger sizes.



3.2.3.6.2 Cultivated plants

Since the colonial period, concrete actions have been undertaken as part of the conservation of cultivated plants. They are:




  • improvement of domesticated species through botanical research, provenance trials;

  • use of at least 40 local species in plantation operations;

  • multiplication and regeneration techniques;

  • improvement of natural formations;

  • research in further knowledge of the biology of species;

  • seeds conservation.

As far as agricultural plants are concerned, the level of species conservation is mediocre because there is no (or almost none) important actions of in-situ conservation of resources. However, the protected forest domains contribute to the conservation of wild species. The fundamental reason behind this situation lies in the country’s difficult socio-economic conditions, which oblige the local populations to seek to satisfy their immediate needs at the detriment of sustainable development. This results in the adoption of new species and varieties having yield and quality higher than those of local species. However, there are a few ex-situ conservation and conservatory installations of phytogenetic resources.

For cereals (sorghum, millet, maize, rice and fonio), local varieties (when they exist), wild forms have been prospected, sampled and preserved in international centres of genetic resources. The duplicates of some of these samples are preserved at the national level in Farakoba. Today, 237 samples of sorghum, 112 of millet, 41 of fonio and rice are preserved there. Oil seeds (groundnuts, sesame and soybean) are preserved in very small quantities in refrigerators and regenerated every two years. Oil seeds such as Cowpeas and Bambara groundnuts are preserved in cold-storage room.

3.2.3.7 Traditional conservation knowledge and practices

Traditional knowledge and practices have sometimes integrated the desired conservation methods of species, biotic communities and consequently genetic resources. These practices are more marked in Africa where there are between man and nature beliefs, messages, correspondences and knowledge. These practices are related to ethnic groups (of which there are more than 60 in Burkina Faso), clans and age group.


Traditional conservation practices of biological diversity in Burkina Faso, like in many African countries are:


  • conservation village forestry relics, called "sacred woods", with cultural or religious goal, constituted of specific species such as Anogeissus leiocarpus (African birch), Combretum micranthum (Kinkéliba), etc., whose sites are chosen by traditional chiefs and elderly people (the wise);

  • the establishment of agroforestry park systems for the preservation of soil fertility and the supply of forestry products to man; the most used species in this framework often have multiple uses; they are, for example, Acacia albida (whitish Acacia, Mimosa), Parkia biglobosa (Nere), Butyrospermum paradoxum (shea-tree Sclerocarya birrea (Sclerocary, Plum-tree), Lannea microcarpa (Grapefruit tree ), Bombax costatum (red kapok tree), Diospyros mespiliformis (Ebony tree Adansonia digitata (Baobab), and Acacia nilotica (Acacia from the Nile);

  • the prohibition by religion or tradition from exploiting some animal species [ex: Canis familiaris (the dog), Equus asinus (the donkey) and Sus cristatus (the big) by the Muslim religion],

  • useful species such as Tamarindus indica (Tamarind) and Stereospermum kunthianum by the Mossi and Bissa, Parkia biglobosa (Nere) used by some Bissa clans for fetishes in the domain of thunder;

  • the traditional regulation of the exploitation of some animal or plant resources (e. g. : organisation of village hunting and fishing), gathering, cereal harvesting;

  • customary practices with an indirect protection of species (customary bush fires) .

Table 24 shows the non-exhaustive list of species being the object of traditional conservation according to the values ascribed to them.


Table 24: List of traditionally preserved species


Ascribed value

Species

Economic

Acacia albida, Adansonia digitata, Borassus aethiopum, Bombax costatum, Butyrospermum paradoxum,Diospiros mespiliformis, Lannea acida,Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Tamarindus indica

Sacred (sacred woods)

Adansonia digitata, Albizia chevalieri, Anthiaris africana, Bligia sapida, Borassus aethiopum,Ceiba pentandra, Combretum micrantum, Cyrtosperma senegalens, Dioscorea dumetorum, Elaeis guineensis, Khaya senegalensis, Pachystela argentea, Pterocarpus erinaceus

Clanic (protection)

Clarias anguillaris, Crocodilus niloticus, Crocodilus cataphractus, Hippopotamus amphibius, Python sebae, Python regius,Tamarindus indica, Varanus niloticus, Varanus exhanthematicus, Gazella dama, Gazella dorcas, Gazella rufifrons, Epomopharus gambianus, Eidelon helvum, Orycterapus afer, Parkia biglobosa

Religious and/or ritual

Equus asinus, Canis familiaris, Sus cristanus

Socio-cultural

Adansonia digitata, Ficus sp., Tamarindus indica, Khaya senegalensis, Sclerocarya birreae

Handicraft and/or customary (masks)

Afzelia africana, Lannea microcarpa, Cassytha filiformis, Canarium schweinfurthii, Tamarindus indica, Adansonia digitata,Gardenia erubescens,Ficus sp., Khaya senegalensis



3.2.3.8 Land use

The available data on land use in Burkina Faso comes form the interpretation of aerial photographs of IGN- France missions taken during the period between 1950 and 1956. The resulting map (Map REMY G. ) reflects the various extents of intensity of land use during the period concerned. One notices a parallel between the data from this map and those from population densities published by SAVONNET in 1965.


The map of land use by RÉMY G. supplies the following data in table 25 for 1956 :
Table 25: Extent of land use


Extent of land use

Area ( km²)

%

Null

Insignificant

Less than 6%

Form 6 to 25%

from 25 to 50%

More than 50%

Uncovered zone


39 800

49 000


86 990

74 900


19 000

2 000


900

14.6

18.0


31.9

27.0


7.0

0.7


0.3

TOTAL

272 500

100

Source: OUADBA J M., 1997
One can notice that only little more than the third of the territory can be considered as populated on average (use > 6-25%) or highly populated (use > 25%)", the level of settlement translating the extent of land use.
An attempt to evaluate the evolution of land use was made in 1991 by GUINKO S., BANDRÉ E. and OUADBA J. M., at the request of the cartographic project Atlas of Burkina, hosted by the ministry of planning. The information available now can be taken from the "Carte de la végétation et de l'occupation du sol au Burkina Faso" by FONTES J. et GUINKO S. (1995). Land use, synonymous with "agricultural domination ", is expressed in three (3) classes according to the percentage of farms and young fallows against the background of natural or spontaneous vegetation. The result of the data is presented in table 26.
Table 26: Area of land use according to class


Class

Area (km²)

%

Low (<10%)

Average (10-30%)

High (>30%)


136,329

73,574


60,938

50.33

27.16


22.50

TOTAL

270,841

99.99

Source :OUADBA J. M.., 1997

Map 12 below gives the extent of croplands use.


Map 12 extent of croplands use

It can be noticed here that half of the country belongs to the class of low land use (136.329 km²). Milieux with higher use account for about 20% of the national territory and correspond mainly to zones including big urban centres (Ouagadougou, Koupéla, Koudougou) where the majority of the country’s population is concentrated.


These authors made it clear that a “rate of less than 10% equals low densities of population and long enough crop rotations-fallows to ensure a good regeneration of soils. On the other, more than 30% of use, the population density is very important and leads to a systematic shortening of the cycle of fallow, lower yields and impoverishes soils”.
By analysing the results from FONTES J. et GUINKO S., it can be estimated that since 1956, and particularly in recent years, the intensity of land use has increased by 17% for all the country. However, this increase does not have the same meaning everywhere, because of the diversity of agricultural practices and the disparity in population densities.

3.2.3.9 Changes noticed at the level of ecosystems and habitats these last 20 years.

Ecosystems and habitats are influenced by dynamics related to climatic variations or changes and to various human activities, including the following: persistent droughts, bush fires, excessive exploitations of biological resources, shifting cultivation and overgrazing. For example, it is mentioned in “Précis de télédétection”, Presse Universitaire du Québec, volume 2, (1996), that the plant landscape of Burrkina Faso underwent from 1972 to 1990 a sudden transformation resulting in two spatial dynamics:




  • in the north, in the Sahelian region, it is a continuous line of degradation which expanded to the south;

  • in the centre as in the south of the country, the evolution occurred in degradation areas which expanded and joined together.



3.2.3.9.1 Terrestrial ecosystems

Savannah and steppe ecosystems have dynamics related to climatic variations, rate of fires, which go through them, and the various human activities affecting them.


According to GUINKO S., 1996, the evolution of plant formations in Burkina has been very high these last twenty years. They suffered from two important drought phases, which are responsible for significant mortality phenomena of ligneous species. These very droughts brought many constraints to the farming and raising populations. Significant displacements of migrants from the north to the south led to pressures on the Sudanese savannahs that are often high.
Today, the north-Sudanese savannahs and the Sahelian steppes all constitute secondary formations resulting from man’s destructive action on the original vegetation through bush fires, clearing, overgrazing and excessive logging for energy and handicraft needs. To these man-made factors, must be added also the effect of climatic drought which has been manifesting itself since 1971 through persistent low rainfall. This persistent climatic drought resulted in the south, in the shift of Sahelian and Sudanese zones. Thus according to DIALLO A. (1990), as compared with the period from 1960-1970, the 500 mm isohyet shifted towards the south by about one degree latitude during the period from 1970-1980.
The degradation of the ligneous vegetation is clearly perceptible in the north-Sudanese zones. The national forestry inventory made in 1980 by FAO (DIALLO A., 1990) estimated that the percentage of dead standing trees reached 4.20% in the north-Sudanese zone and more than 10% in the Sahel. In the Sahelian zone, many populations of Acacia raddiana, Pterocarpus lucens, Dalbergia melanoxylon, Balanites aegyptiaca and de Adansonia digitata are suffering from a worrying decay. OUADBA J.M, 1983 asserts that in the Nakambé basin, 72% of forest formations have declined between 1958 and 1979.
The map of natural vegetation and land use constitutes a source of information on the current status of ecosystems and habitats, which underwent changes in these last 20 years. This map reveals the following forms of vegetation:


  • a few Guinean and humid flora formations in replacement of the Guinean forests along the main streams in the extreme south-west;

  • a few gallery forests which took over from the quite homogenous formations in the Sudanese part;

  • thicket, shrubby and edaphic savannahs;

  • agroforestry parks where the fallowing cycle has been drastically reduced;

  • herbaceous steppes comprising thickets, shrubs and bushes;

  • formations of flood basin zones, marshes and swamps.

Agricultural clearing contributed a lot to the degradation of soils. According to BONKOUNGOU E., 1985 “although all cultivated lands account only for about one third of the 9 million hectares of the country’s cropland, extension possibilities of cultivated lands are actually very limited in some regions because of the mediocre qualities of soils, the low availability of water, or an already high land use leading to even clearing very fragile marginal zones”.


Indeed, it can be noticed that in some regions of Burkina, Yatenga for example, the maximal density threshold (50 inhabitants/km²), considered as compatible with the maintenance of soil fertility has been largely exceeded in the present context of traditional production systems, technical conditions, and natural and human conditions of agricultural and pastoral activity (BOGNOUNOU O., 1996).
This aspects of degradations related to clearing, human and pastoral toll, the deterioration of living environment is well shown in the world map of desertification (UNEP/FAO/UNESCO) where the majority of Burkina is classified in the high risk desertification zones.

Concerning the particular case of specific ecosystems, it is worth mentioning the overall degradation of forest galleries in the agro-ecological zone further south of the country (Comoé, Léraba, Mouhoun). As a result of their protective role of banks and springs, sensitive habitats of the hydrographic network, uncontrolled clearing of forest galleries constitutes a major ecological risk with incalculable consequences (BOGNOUNOU O., 1996).


In the west of Burkina, rural migrations increased in recent years. In the absence of lands, migrants consciously or unconsciously settled illegally in many protected forests. Drawing inspiration from a few displacement actions, the forestry administration is looking for a global and adapted strategy to make illegal settlers leave these forests.

3.2.3.9.2 Freshwater ecosystems

Chronic rainfall shortages recorded for more than two decades have resulted in the non-filling of water points and in the decline in the flow of streams. Ponds, lakes and other water bodies have since then been undergoing various pressures, which led to their silting. This resulted in the quantitative and qualitative modification of aquatic fauna. In addition, the use of chemical fertilisers in irrigated cash crop farms contributed through the weathering phenomenon to pollute water bodies, making ecosystems unbearable for fauna, hence the loss of many specimen and the decline in the number of fauna and herbaceous species.


Animal action at the level of ponds also contributed to their modification. Indeed, the plant biomass produced by ponds, containing many fodder species (47.3 %) of flora (in Sahelian zone), is invaded by many herds. Animal grazing and trampling lead to a rapid degradation of the vegetation and to few modifications, translated into the appearance of new faeces (Nymphaea lotus and Utricularia stellaris).

3.2.3.9.3 The main changes occurred in the last 20 years in the populations of some plant species.

Biological diversity in Burkina Faso was once very rich in flora and fauna. Today, populations of some important species suffer from pressures due often to uncontrolled exploitations, clearing and bush fires.

The Sahelian domain is now predominated by Phanerophytes (1.37%), which are ligneous species (mainly Acacia), and Therophytes (61%), i.e. annual graminae. The populations of some Acacia of fodder utility have been vulnerable because of the extent of pruning and regeneration difficulties related, on the one hand, to the rainfall situation which is more and more difficult, and on the other hand, to the grazing and trampling of seedlings, when they exist, by cattle.
In the Sudanese domain where agricultural activities predominate, clearing leads to the extinction of entire populations of species; only useful species are saved during clearing.
Logging concerns all the ligneous species traditionally used as timber. The targeted species are numerous. In the absence of statistics concerning the proportions of the most sold species or prized, it can be noticed that:


  • Detarium microcarpum (Detah with small fruits) is always very much exploited in its distribution area. This species does not seem be in danger because of the strength of stump sprouts;

  • Prosopis africana (Prosopis from Africa) has sparse populations and its regeneration is endangered by logging (it has a high calorific power). Burkea africana (Kurkea from Africa) is in the same situation;

  • Butyrospermum paradoxum subsp parkii (Shea nut tree), although protected, is fraudulently and excessively exploited.

Today, since the demand is very high because of the population increase in the urban milieu, and rural migrations in the west is important, we are experiencing an important logging of fresh wood for fuel. In Bobo-Dioulasso, it can be noticed that since the devaluation of the CFA Franc in 1994, the number of wood traders has increased a lot.


For example, it has been pointed out that the Kou massif is very deteriorated particularly because of fraudulent logging and the negative impact of visitors. In the Mangodara region, clearing for the cultivation of yam has degraded the soils and the vegetation up to the north of Côte d'Ivoire. These human disruptions caused the scarcity of some species of fauna in Dindérésso and Folenzo.
Around big urban centres, some protected species such Butyrospermum paradoxum (Shea nut tree) suffer from excessive fraudulent logging, which results in the decline of the populations of such species. In addition, the reduction of fallow period contributed to the scarcity of species and populations in the agroforestry parks of neere (Parkia biglobosa), shea nut tree (Butyrospermum paradoxum), Tamarind (Tamarindus indica), grapefruit tree (Lannea microcarpa), plum-tree (Sclerocarya birrea), etc. Actions undertaken as part of the "three struggles " (struggle against bush fires, struggle against excessive logging and struggle against animal ranging) have now been reinforced by a policy aiming at associating local communities to the rational exploitation and sustainable management of forests, for example, the protected forest of Nazinon, the protected forest of Gonsé, the GEPRENAF project, the project GEF/Nazinga project, the protected areas project and the conservation of biological diversity in the east of Burkina Faso, etc.

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