Invasive alien plant species used for the treatment of various diseases in Limpopo Province, South Africa

Abstract

Background: Invasive alien plant species (IAPs) are plants that have migrated from one geographical region to non-native region either intentional or unintentional.The general view of IAPs in environment is regarded as destructive to the ecosystem and they pose threat to native vegetation and species. However, some of these IAPS are utilized by local inhabitants as a substitute for scarce indigenous plants. The aim of the study is to conduct ethnobotanical survey on medicinal usage of invasive plant species in Waterberg District, Limpopo Province, South Africa.

Materials and methods: An ethnobotanical survey on invasive plant species was conducted to distinguish species used for the treatment of various ailments in the Waterberg, District in the area dominated by Bapedi traditional healers. About thirty Bapedi traditional healers (30) were randomly selected via the snowball method. A guided field work by traditional healers and a semistructured questionnaire was used to gather information from the traditional healers. The questionnaire was designed to gather information on the local name of plants, plant parts used and methods of preparation which is administered by the traditional healers.

Results: The study revealed that Schinus molle L., Catharanthus roseus (L.), Datura stramonium L., Opuntia stricta (Haw.) Haw., Opuntia ficus- indica, Sambucus canadensis L., Ricinus communis L., Melia azedarch L., Argemone ochroleuca and Eriobotrya japonica are used for treatment of various diseases such as chest complaint, blood purification, asthma, hypertension and infertility. The most plant parts that were used are 57.6% leaves, followed by 33.3% roots, and whole plant, seeds and bark at 3% each. Noticeably, most of these plants are cultivated (38%), followed by 28% that are common to the study area, 20% abundant, 12% wild,
and 3% occasionally. Schinus molle is the most frequently used plant species for the treatment of various ailments in the study area. National Environmental  Management Biodiversity Act (NEMBA) (10/2004) and Conservation of Agricultural Resource Act (CARA) were consulted to confirm the invaders status. Only eight plants (60%) are regulated by CARA (10/2004). Of 10 IAPs, 80% (8 species) are listed in both NEMBA and CARA legislation. Only 20% (2 species) are listed in NEMBA alone.

Conclusion: Invasive alien plants are utilized by communities to combat various  ailments in humans and these plants can help to reduce pressure on heavily harvested indigenous plant.

Key words: Ethnobotanical survey, Invasive plant species, Traditional healers.