Use-value and importance of socio-cultural knowledge on Carapa procera trees in the Sudanian zone in Mali

This study was conducted during the years 2011–2012 in two villages, Ziékorodougou and Niankorobougou, in the Sikasso region of Mali for general surveys and in four other villages, Sougoumba, Soungoulasso, Founa and Bounou, for interviews with key informants.

The Sikasso region is located in southeast Mali, 12° 30′ N and 8° 45′ W bordering Ivory Coast and Burkina Faso (Figure 1). The climate of the region is Sudanian to northern Guinean with 750 to 1400 mm [30]. The average annual temperature is 27°C. The vegetation of the region is mainly composed of woodland, wooded grassland, grassland, shrubland and gallery forest. The population of the region is mainly composed of following ethnic groups: Senufo, Minianka, Fulani, Samogo, Bobofing and Bambara.

Carapa procera belongs to the Meliaceae family. In West Africa, three species are found: Carapa microcarpa, Carapa procera and Carapa velutina[31]. This study focused on Carapa procera DC., a woody species of Sudano-Guinean affinity growing along gallery forests and rocky faults [32]. Carapa procera is a large trees up to 30 m tall, occurring in a wide range of habitats from gallery forest in savanna areas to humid forest in western and central Africa [33]. Seed regeneration is the dominant form of species renewal [32]. Carapa procera is an oleaginous plant species traditionally exploited by rural communities in southern Mali. In the local language Bamanakan it is called “kobi”. Carapa procera plays an important role in the socio-economic and cultural life of local populations. The products are mainly used for oil and soap, because of their therapeutic and cosmetic properties. The oil extracted from nuts of Carapa procera has various medicinal applications, as insecticide and repellent and for veterinary care of animals. In addition to traditional uses, the oil is used for the phytosanitary treatment of organic crops such as cotton [32]. The leaves, bark and roots are also used in the treatment of some diseases as skin and gastrointestinal diseases [34]. Exploited products, particularly oil, are sold in local markets and bring substantial income to producers, especially women.

Data collection was conducted using adapted semi-structured ethnobotanical questionnaires described by Lykke et al. [12]. Formal surveys were conducted in the villages of Ziékorodougou and Niankorobougou. The choice of these localities was based on the presence of a natural stands and local use of Carapa procera by local communities.

In each village, we held a first meeting with the village chief and his advisors to inform them of the purpose of our work. Two ethnic groups were chosen: Senufo and Fulani in Ziékorodougou, Bambara (Dioula) and Fulani in Niankorobougou. The survey covered 12 informants within each ethnic group of which six were men and six women (Table 1). The choice of informants was made in collaboration with village leaders. Informants were chosen randomly among those who have knowledge about Carapa procera. The interviews were conducted individually in the local language “Bamanakan”. The information collected during these investigations focused on general knowledge of Carapa procera, characteristics of the parts exploited, collection period, use categories and reasons for use. Here, a use category is defined by all uses of the same nature according to the method of Van Andel [1].

Supplementary interviews were conducted with other contact informants during prospective missions for more detailed information. Interviews were followed up by participant observations of processing and use of Carapa procera products according to Martin [17].

All participants were informed of the objectives of the study and that the results would be used for a scientific publication.

The following ethnobotanical quantitative and qualitative methods were used for data analysis.

The frequency of exploited plant parts (F) from Carapa procera was evaluated through the response rate by type of plant part according to the formula:

S: the number of informants who responded positively to use a plant part; N: the total number of informants. F = 0 indicates that the plant part is not used; F is 100 when the part is used by all informants.

The formulas described by Monteiro et al. [35] were used to know the degree of agreement among informants on the plant parts exploited and the forms of use.

Consensus value for plant parts exploited (CPP):

P_x: the number of citations of a plant part exploited; P_t: the total number of citations of all plant parts.

Use values of Carapa procera were evaluated through the parameters that indicate how the exploited plant parts are used and how the knowledge of these uses is allocated among informants. The following formulas described by Byg & Baslev [36] were used.

Importance of use categories was evaluated through the use diversity value (UD) according to the formula:

U_CX: the number of indications recorded by category of use; U_Ct: the total number of indications for all categories of uses.

The use equitability value (UE) was calculated to know the degree of homogeneity of knowledge about use categories;

UD: use diversity value; UD_max: the maximum value of the diversity index.

The degree of agreement among informants concerning the form of use was measured trough the formulas in [35]. Consensus value for the forms of use (CMU):

M_x: number of citations for a form of use; M_t: total number of citations for all forms of uses.

The fidelity level (FL) was calculated for the specific purposes of use of exploited plant parts following the formula of Friedman et al. [37]:

Where n is the number of informants for a specific use, and N is the total number of informants.

In the study area, Carapa procera is identified through various local names (Table 2). The prefix of local names, “ko” in Bamanakan, “dugu” in Senufo and Minianka language means backwater and refers to the traditional habitat of the species. This shows that Carapa procera is a species traditionally listed along watercourses such as backwater and rivers.

Several plant parts of Carapa procera were exploited by local communities: roots, bark, wood, gum, leaves, nuts (Figure 2a) and mistletoes (Figure 2b). Mistletoes are parasitic plants from the Loranthaceae family growing on branches of some trees and collected for magical and spiritual purposes. The F indicates that nuts were mentioned by all informants (100%) followed by leaves and bark with 21% each (Figure 3). CPP showed that nuts constituted 57% of the citations of exploited plant parts, followed by bark and leaves (12%), wood and roots (7%), mistletoes (4%) and gum (1%) (Figure 4). Field observations have revealed the impact of the bark exploitation that may have adverse effects on the survival of the species (Figure 5). Nuts are usually collected at the beginning of the rainy season during the months from May to June. The other plant parts are exploited in any period.

Tables 3 and 4 show the consensus value for plant parts exploited (CPP) according to ethnic group and gender of informants. Nuts have obtained the highest consensus values irrespective of the ethnic group and the sex. Women showed a higher consensus value for nuts (0.71) than men (0.48). The consensus value for bark harvesting was higher for men (0.16) than for women (0.06) in Ziékorodougou. In Niankorobougou, the CPP for bark harvesting was the same (0.12) for both sexes.

The plant parts exploited are used for different purposes, which can be grouped according to use categories: therapeutic, cosmetic, veterinary, energy, plant treatment and ritual/spiritual. The cosmetic and therapeutic uses have got the highest percentage of use categories (49% and 36%, respectively) (Figure 6). Tables 5 and 6 show the UD and UE of use categories according to the ethnic groups and gender. Comparative analysis between ethnic groups revealed that the highest UD for cosmetic uses (0.63) was observed in the Bambara ethnic group, whereas the highest UD for therapeutic uses (0.39) was obtained in the Senufo ethnic group. The UD for therapeutic uses was higher for ethnic groups in Ziékorodougou than in Niankorobougou. In contrast, the UD for cosmetic uses was higher for ethnic groups in Niankorobougou than in Ziékorodougou. Veterinary uses were recorded particularly in Fulani ethnic group in both locations. Ethnic groups in Ziékorodougou reported uses of Carapa procera for plant protection. The Senufo ethnic group indicated spiritual and ritual uses of Carapa procera. Related to gender, the use diversity values showed that cosmetic uses were higher for women than for men. The therapeutic uses showed similar values for men in both locations (UD = 0.36). However, women in Ziékorodougou showed the highest value of therapeutic uses (UD = 0.40) in contrast to women in Niankorobougou, who presented the lowest value of therapeutic uses (UD = 0.30).

Forms of use are varied. Leaves, roots or bark can be used fresh or dried according to the forms of use desired through infusion, decoction, powder or smoking. Nuts are processed into oil and soap. Soap (45%) and oil (30%) were the most common forms of use adopted by the local communities (Figure 7). There were variations in CMU among ethnic and gender groups (Tables 7 and 8). The CMU showed that oil uses were higher for women (0.33) than for men (0.28). Women showed a higher consensus value for soap uses (0.50 and 0.57) than men (0.34 and 0.44) respectively, in Ziékorodougou and Niankorobougou. The lowest CMU were observed for soap use by the Senufo (0.39) and the men (0.34) in Ziékorodougou. Leaves, bark and roots of Carapa procera were exploited and used as an infusion and decoction. In both locations, the use of decoctions has been more significant for men (CMU = 0.13 and 0.16) than for women (CMU = 0.04 and 0.09). Smoking of dried gum for magico-spiritual uses has been reported by the Senufo ethnic group.

Figure 8 show the sociocultural values for Carapa procera plant parts.

The treatment of skin diseases, gastrointestinal, body care, animal healthcare and phytosanitary treatment of plants are among other, the reasons to use Carapa procera. Tables 9 and 10 show the FL of use of Carapa procera according to the ethnic groups and the gender of informants. The uses for body care and household sanitation have received the greatest level of fidelity. Wound and injury care treatment of gastrointestinal diseases and treatment of skin diseases have also been common reasons of use. The Senufo ethnic group indicated the use of dried powder for agricultural seed conservation and burying of whole seeds to field boundaries for crop protection. Insecticide treatment of crops was mentioned by the Senufo and Fulani ethnic groups in Ziékorodougou.

Informal interviews revealed that the powder of dried nuts in combination with other products has aphrodisiac virtues. The hulls of fruits are used as anti-inflammatory for the treatment of swelling.