Invasive alien plants occurring in Lesotho: Their ethnobotany, potential risks, distribution and origin

Background: Several recent studies have documented the ethnobotanical uses of plants used in Lesotho, in particular those used for medicinal purposes. However, these reports did not make a distinction between indigenous, naturalised or invasive alien plants. Furthermore, the existing records on the status of the occurrence of these plants in the country are not up to date. Objectives: The aim of this article is to present information on the current knowledge regarding the status of invasive alien plant species in Lesotho and to discuss their ethnobotanical uses, distribution in the country, origin and safety. We further assess the existing legislation designed to regulate the spread of such plants and make a comparison with the invasiveness and regulation of such plants in the neighbouring South Africa. Method: This article is based mainly on a literature survey of published information obtained from various databases, such as Google Scholar, Science Direct and Scopus, as well as from unpublished data such as technical reports, dissertations and theses. Results: A total of 57 species, comprising one pteridophyte, one gymnosperm and 56 flowering plants (52 dicotyledons and 4 monocotyledons) are documented. Although these plants are invasive in nature, they are utilised for a variety of purposes including food, treatment of various medical conditions, cosmetics and functional uses. However, some of the species are reported to be poisonous to both animals and humans, with a majority of the plants causing skin irritation. Most of these species are widely distributed throughout the country and most of them originated from America, Europe and Asia. Although a number of reports on the occurrence of invasive alien plants have been generated, the information therein has not yet been published. Conclusion: This study has identified knowledge gaps in terms of safety and distribution of the species, as well as shortfalls in the policies intended to regulate invasive alien species (IAS) in Lesotho. Further research in this regard is therefore recommended.