Medicinal plants sold by west, central and east African immigrants in Johannesburg, South Africa.
South Africa hosts >1.2 million immigrants, 75% from Africa. The inter- and intra-continental diaspora of immigrant groups, and the movement of biological commodities, effects a parallel biological diaspora of plants, animals, and pathogens to regions where they are non-native, and an allied diaspora of traditional practices associated with commodity use. Plants with dual purposes of food and medicine are repeatedly introduced into new countries by waves of immigration. The motivation for species selection may reflect cultural importance, geographic origin, and diseases associated with migration. With this in mind, this study aimed to investigate medicinal plants, and their uses, which are imported by immigrant traditional healthcare traders in Johannesburg, and highlight routes of alien plant introduction. Semi-structured interviews with 25 immigrant traders originally from the Democratic Republic of Congo, Ethiopia, Eritrea, Ghana, Nigeria and Somalia were conducted. Sixty-six species were recorded (60 alien to South Africa) that treated conditions in 15 broad biomedical categories. Species were primarily imported to treat non-communicable diseases (NCDs), with the most frequently cited being for diabetes, back pain, influenza, stomach pain, haemorrhoids, and male sexual performance. The use of medicinal plants from 'home' is assumed to strengthen an immigrant's sense of cultural identity in a new country, with some plants seemingly too important to leave behind; the diseases linked to these selections were affiliated more with 'disease of transition', including NCDs. Some imported species require assessments of risk to becoming invasive. These results flag the international traditional medicine trade as an introduction pathway for alien plants.