Do not fear the supernatural! : the relevance of ritual plant use for traditional culture, nature conservation, and human health in western Africa

Summary Plants still play an overriding role in African traditional medicine, as large sectors of the continent’s population prefer or considerably rely on herbal treatments as their primary source of health care. Traditional medicine, which is defined as the sum of knowledge, skills, and practices used to prevent and treat diseases, often involves consultation with spiritual healers and diviners, who in turn consult supernatural entities to diagnose their patients. At the same time, these traditions and the rites that are related to their practice are categorised as “obscure” and considered unscientific by academia. The overall aim of this thesis was to advance the understanding of the different dimensions of plant use in the context of traditional religions in two western African countries: Benin and Gabon. First, by documenting the use of plants by adepts of Vodoun in Benin and Bwiti in Gabon; and second, by exploring the associated knowledge that sustains these practices. Its purpose was to contribute to an improved plant resource management and, ultimately, the development of culturally appropriate interventions aimed at the conservation of useful plant species and their ecosystems, as well as the improvement of human health in settings similar to those of our countries of study. Departing from the disciplinary perspective of ethnobotany, this work included theories and quantitative and qualitative methods of data collection and analysis drawn from botany, anthropology, ethnology, ecology, and pharmacology. Data were collected in a period of more than a year, which was divided in two fieldwork stays, each in Benin and Gabon. This thesis was organised into six chapters. In Chapter One, I laid out the conceptual framework and introduced the study sites. Based on an assessment of the relevance of this study, I framed its overall objective and research questions. Medicinal plants are not only acknowledged for their importance in satisfying the health needs of people in sub-Saharan Africa, but also for the role their commercialization plays as a source of income for vulnerable groups. In spite of this recognition, little is known about the implications of medicinal plant trade for the sustainability of the plant species involved, especially when data on the volume and diversity of species sold at the markets are not available. In Chapter Two, we addressed this gap by providing an estimation of the volume and economic value of the domestic market in herbal medicine in Benin. We also highlighted local health concerns reflected by the medicinal plant market and found that ritual plants were the largest use category for which vendors catered in the markets of Benin. Additionally, we suggested some species with possible sustainability issues. In Chapter Three, we explored the potential link between two different social mechanisms that regulate the use of plant resources (taboos and sacrifices) and the scarcity of ritual plants in Benin and Gabon. The scholarly discussion around the origin and necessity of taboos has found these to exist either as a means to avoid potential diseases or to control the use of natural resources. Moreover, empirical data has shown that taboos reflect resource abundance. These studies, however, have primarily focussed on the use of wild animals as food. By providing quantitative data based on questionnaires with local informants, we found evidence that restrictions (such as taboos and sacrifices) were an indication of resource scarcity of ritual plants, thus advancing new explanations to the existence of these social mechanisms. In Chapter Four, we revised two of the notions that are central to our study: ‘religion’ and ‘traditional religion’, this time as defined by the people who profess these faiths in Benin and Gabon. Plant use in the context of traditional religions has been commonly described from an outsider’s perspective. The same is true for religion and traditional religions. In this chapter, we learnt that plants played a central role in the religious traditions of Benin and Gabon, both for adepts and non-adepts of Vodoun and Bwiti. In Western science, the effects of ritual plants on human health have been proposed to be a matter of belief. In Chapter Five, we discussed the potential pharmacological effect of culturally salient and economically important ritual plants on their users. We did that by contrasting their mode of application to proven pharmacological properties gathered from the literature. Additionally, we described folk categories of illness related to supernatural agents (e.g. evil spirits, ancestors, and sorcerers), as well as diseases recognised by biomedicine but that are attributed supernatural causes by people in Benin and Gabon. We discovered that in both countries an important proportion of the ritual applications of plants suggest a pharmacological effect on their users. Finally, in Chapter Six, I addressed the research questions formulated in Chapter One and discussed our work’s methodological issues as well as its implications to other scientific disciplines. I also highlighted the possible applications of the research results in informing nature conservation and human development interventions, as well as some possibilities for future research. Moreover, I reached five conclusions about Bwiti and Vodoun in our countries of study: (1) Plants and other elements of the natural world play a central role in the religious traditions of Benin and Gabon, both for adepts and non-adepts of these traditions. (2) Social mechanisms such as taboos and sacrifices are a form of adaptive management of plant resources that respond to perceived scarcity of ritual plants by their users. (3) Ritual applications of plants used in our countries of study suggest a pharmacological effect on their users, as opposed to the previous assumption that their effectiveness is a matter of belief. (4) By being the backbone of the medinal plant trade in Benin and Gabon, ritual plants represent an important source of income for a substancial sector of the population of these two countries. (5) The Western notion of ‘ritual’ in the context of western African plant use is an important mechanism for the preservation and transmission of ecological, historical, and medicinal knowledge. These conclusions point to the need to question the assumptions upon which the study of plant use in the western African context has been typically approached. Finally, I concluded that as long as the exercise of agency by supernatural entities is acknowledged, considering these practices as ‘religious’ is justified from an etic perspective.