Medicinal plants trade in Harare's urban markets: diversity, conservation status, and economic significance

Abstract

Background: Urban markets serve as crucial centres for trading traditional medicinal plants, yet there is limited research on the diversity, geographic origins, and socio-economic contributions of these plants. Therefore, this study aimed at understanding the species composition and diversity, conservation status, and economic importance of medicinal plants in urban markets of Harare, Zimbabwe, to provide insights into their sustainability and cultural significance.

Methods: This study surveyed medicinal plant vendors in three major urban markets in Harare, Mbare, Highfield, and the Central Business District (CBD) in 2019 over a period of three months. Data were collected through semi-structured questionnaires to inventory medicinal plant species, document vendors' districts of origin, and assess harvesting practices. Species diversity was analysed using Shannon-Wiener and Simpson diversity indices, while Non-metric Multidimensional Scaling (NMDS) was used to compare species composition across markets. The informant consensus factor (ICF) was calculated to determine the level of agreement among vendors on the medicinal use of plant species.

Results: A total of 64 medicinal plant species were identified, with Fabaceae being the most represented family. Sixty-one species were in the least concern IUCN Red List category. Key species with high use reports included Entada goetzei (62), Cassia abbreviata (58), Pterocarpus angolensis (40), and Albizia anthelmintica (31). Roots were the most sold plant part, followed by bark and leaves. Mbare exhibited the highest species richness (54), followed by Highfield (34), while the CBD recorded the lowest richness (23). Non-metric Multidimensional Scaling (NMDS) analysis revealed distinct differences in species composition among the three markets (R = 0.492), with Highfield displaying a unique suit of medicinal plant species. Vendors primarily originated and sourced their medicinal plants from eastern Zimbabwe, particularly Chipinge, highlighting a strong link between plant sourcing and geographic origin. The ICF was highest for gastrointestinal disorders (0.807), women's health (0.778), sexually transmitted infections (0.746), and labour-related ailments (0.842). Medicinal plant trade contributed significantly to vendors' livelihoods, with monthly incomes ranging from US$150 to $300.

Conclusion: This study underscores the high diversity of medicinal plants and their socio-economic importance in Harare's urban markets. This shows that traditional medicine is still considered important in primary health care in the city of Harare. However, the reliance on distant districts (~ ≥ 100 km) for plant sourcing raises concerns about the possibility of unknowingly overharvesting.

Keywords: Diversity; Harare; Informant consensus factor; Medicinal plants; Public markets; Use report.

Fig. 1

Map showing the location of the city of Harare in Zimbabwe (a) and the location of sampled markets in Harare as black dots (b)

Fig. 2

Comparison of incidence-based interpolation and extrapolation for a species richness (q = 0), Shannon–Wiener diversity (q = 1) and Simpson diversity (q = 2), b individual-based interpolation and extrapolation for sample coverage, and (c) sample coverage-based interpolation and extrapolation for species richness (q = 0), Shannon–Wiener index (q = 1) and Simpson index (q = 2) compared across the three study sites, Mbare, CBD and Highfield. All extrapolation curves were plotted to double the sample size, and 300 bootstrap replicates were used to estimate 95% confidence intervals (shaded area)

Fig. 3

Non-metric multi-dimensional (nMDS) scaling ordination of ethnobotanical species sampled for three medicinal markets, Mbare, Highfield and CBD

Fig. 4

a Number of vendors by district of origin sampled from the three markets, CBD, Mbare and Highfield in Zimbabwe and b Number of vendors harvesting medicinal plants per district across Zimbabwe, as sampled from the three markets, Mbare, CBD and Highfield

Fig. 5

The relationship between the number of vendors harvesting from a given district and the number of vendors originating from the same district

Fig. 6

Mean ± standard error of money generated by vendors in the three study sites. Dots represent the means, and whiskers denote the standard errors. Sites with different letters indicate significant differences in income obtained by vendors per month