Use and socio-economic values of Ricinodendron heudelotii (Bail.) Pierre, a wild oil species in Benin

Ricinodendron heudelotii is a wild oil tree species native to sub-Saharan Africa. It is also found in Benin. Its oil is rich in the essential fatty acids (Omega 3, 6), fat-soluble vitamins (A, D, E and K) and trace elements, essential for human health. Currently, few people know about this oil, likely explaining its almost total absence in rural markets in Benin. The species is also neglected, as little scientific data is available on it in Benin, particularly regarding knowledge on its uses where it occurs. With the aim of filling this gap, ethnobotanical surveys were undertaken to assess the uses of the species, identify factors explaining the variation of its ethnobotanical value, and determine its availability and accessibility for local people. Data were analysed using the relative frequency of citation and generalised linear models. In total, eight uses were enumerated, of which six were for medicinal uses and one for cosmetic and handcraft respectively, and mainly based on its stem. The stem of R. heudelotii was mainly used for handcraft by Nagot and Holli socio-linguistic groups and mainly by men from the Pobe phytodistrict. Although individuals of R. heudelotii were absent in southern Benin, its kernel is mainly used for cosmetics and medicine by people from the Fon socio-linguistic group in this region. Field data suggest that the kernels and oil of R. heudelotii in this region mainly come from Cameroon and Côte d’Ivoire. The distance travelled to access the species at the time of this study is two times higher than 30 years before and positively correlated with the use-value (r=0.66, P-value<0.001). Our findings suggest that R. heudelotii is marginally used in Benin, and this might be a threat for its conservation and related knowledge.