Assessment of the impact of artisanal gold mining on agriculture and natural resources using Landsat imagery - A case study on Central Côte d'Ivoire

Abstract

With gold mining booming in Côte d'Ivoire, the environmental and socio-economic impacts have become a cause for concern. Between 2013 and 2023, the sub-prefecture of Kokumbo, in central Côte d'Ivoire, was subject to illegal and uncontrolled gold mining. The aim of this study was to assess the impact of this exploitation on natural resources (forests, savannahs, and water) and agriculture. To achieve this objective, Landsat satellite images were analyzed using machine learning algorithms to perform supervised classification. This approach was used to map and quantify changes in land use and land cover over the study period. The “random forest” algorithm provided the best classification and was used for the classification of the time series of Landsat images. The results indicated a regression of 14.64 % of forest areas, 7.12 % of savannah areas, 0.14 and 0.03 % of water bodies and an increase of 19.89 % of agricultural land. Approximately 89 ha (or 0.21 %) of the surface area of ​​the Kokumbo sub-prefecture were converted into gold mining areas. This conversion concerned 40 ha of savannah areas, 21 ha of agricultural land, 14 ha of forest areas, 11 ha of inselbergs and 3 ha of bare areas. In conclusion, artisanal gold mining has been a key driver of land use change dynamics, affecting agricultural lands and natural ecosystems. These impacts could compromise ecosystem services on which local communities depend.