Transmission of local knowledge on medicinal plants along an urbanization gradient in Southern Bénin

Abstract

Urbanization leads to a progressive erosion of ethnobotanical knowledge, compromising the intergenerational transmission of medicinal plant knowledge. The objective of the study was to analyze the impact of urbanization on the diversity of known medicinal plants and the modes of knowledge transmission in southern Benin. A survey was conducted among 480 individuals from 120 households across six localities representing urban, peri-urban, and rural zones. The diversity of medicinal plants was assessed by counting cited species and analyzed using ANOVA and a generalized linear model (GLM). Results showed that medicinal plant diversity decreased with urbanization, with 34 species recorded in urban areas, 61 in peri-urban areas and 56 in rural areas. Parental transmission (85%) remained the dominant mode, but was weaker in urban settings, where accessed to modern healthcare and reduced green spaces accelerate knowledge loss. Exotic plants represented 50% of the cited species in urban areas, while native plants predominated in rural environments. These findings confirm that urbanization alters ethnobotanical practices and reduce the transmission of traditional knowledge. Preserving this knowledge requires documentation, education, and the promotion of medicinal plants, while further studies on the medicinal efficacy of the cited species and large-scale analyses are recommended to better understand knowledge transmission dynamics in an urbanization context.