Use of local knowledge for contributing to the conservation of Caesalpinia bonduc (L.) Roxb in southern Benin (West Africa)

Natural resources such as medicinal plants are important in the livelihood systems of many local people around the world. The high anthropogenic pressure on these species lead to their progressive disappearance. This is the case of Caesalpinia bonduc, a medicinal plant widely used in southern Benin but already extinct in the wild. The remaining individuals can only be found in agroforestry systems and home gardens. Therefore, it is necessary to assess the factors responsible of the decline of the species for its sustainable conservation. This study aimed to assess traditional knowledge, perceptions and strategies for an effective management of the species in southern Benin. A semi-structured interview was conducted with 602 household heads randomly chosen from 19 localities. The fidelity level (FL), index value related to useful organs (IVO) and Overall ethno-botanical use value (OUV) of the species were estimated. To describe ethnic groups-related differences, a principal component analysis (PCA) was implemented on OUV. Chi-Square test was used to check the dependence between socio-demographical characteristics of the respondents and local perceptions and strategies. A factorial correspondence analysis (FCA) was then performed on the citation frequencies of different variables to describe the relationship between ethnic groups and local perceptions and strategies. In total, 20 use properties were reported for the species with 10 previously undocumented uses of the species. The roots are the most used organ with IVO = 50%, followed by the leaves (IVO = 45%). The species is most used in traditional human medicine (FL = 100%). A strong relationship was found between ethnic groups and use of the species but also between ethnic groups and perceptions and management strategies. Respondents acknowledged that the species has decreased (80% of them) and even has disappeared (18%) in the wild. According to the informants, the main causes of the decline of the species are roots overexploitation (53.7%), intensive use in traditional pharmacopoeia (37%) and agriculture expansion (32.6%). Respondents also acknowledged that there is an urgent need for the species conservation (96%). Reduce intensity of harvesting plant parts, cultivating the species in nurseries, planting and protecting seedlings in fields were cited as methods of conserving the species. This study provides a precious contribution to the conservation of C. bonduc in southern Benin. Therefore, we recommend for any actions aiming to rehabilitate the species in its natural stands, local people’ priorities and knowledge should be considered.