An investigation of the social impact of Solanum mauritianum (Bugweed) on Gauteng farmers, and the geographical distribution of Bugweed in Gauteng

A research report to the Faculty of Science in fulfilment of the requirements for the degree: Master of Science In Environmental Science (Coursework & Research), Johannesburg 2018Bugweed (Solanum mauritianum Scop. Solanaceae) is a NEMBA category 1b, alien invasive plant species that originates from South America. In South Africa Bugweed is abundant in the eastern part of the country, especially where rainfall is high. Previous studies have focused mainly on the ecological and economic impacts as well as the control of alien invasive plants including Bugweed in South Africa. However, these studies have not addressed the social impact of the weed on the various stakeholders including farmers. The understanding of the social impact of Bugweed on farmers will enable us to quantify the amount of damage caused by this weed at a social level, and also to explore potential benefits that could be derived from the infestation. The study also sought to determine the geographic distribution of Bugweed within Gauteng using remote sensing. This will form part of an integrative approach towards combating the negative impacts of Bugweed invasion. Interviews were conducted across five of the areas that are regarded as agricultural hubs in the Gauteng Province. A total of 50 farmers were interviewed. The interviews were aimed at assessing the farmers’ sources of information regarding Bugweed and other invasive alien plants (IAP), their level of knowledge regarding Bugweed, and lastly their perceptions regarding Bugweed. Farmers Organisations were identified as the main source of information farmers are exposed to. Only 38% of the participants (farmers) knew Bugweed. The level of knowledge amongst the participants regarding Bugweed is surprisingly low, and it is very difficult to assess people’s perceptions about something they are not familiar with. However, there are those participants who are familiar with the weed who do not regard it as a pest. Bugweed does not appear to have any social impact on the majority of the participants. The study also explored the feasibility of applying remote sensing to discriminate Bugweed from coexisting plant species within the Gauteng Province, using both field spectroscopy (ASD) and satellite imagery for the purpose of mapping and monitoring. The discrimination of Bugweed from other plant species within the Gauteng Province is possible, and thus the use of remote sensing to monitor Bugweed within the Gauteng xiv | P a g e Province should be encouraged. In order to improve the results, it is recommended that satellite imagery of a higher spectral resolution (hyperspectral imagery) must be used, and most importantly the number of the co-existing plant samples and classes should be increased.XL201