Mapping the spatial distribution of Lantana camara using high-resolution SPOT 6 data, in Mpumalanga communal areas, South Africa

Abstract

Agroecosystems play a critical role in rural economics and contribute to the national economy. However, these areas are currently threatened by invasive species. Timely information on potential hotspots and affected areas is required for management purposes. We assess the spatial distribution patterns of Lantana camara invasion in savanna rangeland ecosystems before and after clearing (2014, 2016 and 2018), using high-resolution SPOT 6 data, in Agincourt, South Africa. A maximum likelihood classification algorithm was applied to SPOT 6 data to detect and map areas affected by this invasive species. Furthermore, different accuracy assessment measures (e.g. producer accuracy (PA), user accuracy (UA) and overall accuracy (OA)) were used to assess the validity of the classification results, namely built-up areas, bare areas, uninvaded areas and invaded areas. The results demonstrate that Lantana camara occurrence in rangelands ecosystems can be mapped with high accuracy. An overall accuracy of 81.29% was attained for 2014, 86.85% for 2016 and 88.69% for 2018. It was further observed that in 2016 Lantana camara occurrence was minimal when compared to 2014, but the results indicate regeneration in 2018 in previously cleared areas. Approximately 40.84% of the area was covered by Lantana camara in 2014, 25.19% in 2016 and 27.02% in 2018. Overall, the findings in this study underscore the need for continuous monitoring of affected areas, especially after clearing, to continuously advise on areas that are at risk for potential re-establishment of invasive weeds.