Satellite detection of vegetation loss in artisanal and small-scale mining regions of Ghana

Abstract

Artisanal and small-scale mining refers to labor-intensive and low-tech mineral extraction and processing that usually follows no formal mining regulations. The extent of environmental damage caused by small-scale mining has generated sensitive discussions in Ghana, warranting the need to quantify the amount of mining-related environmental loss. This study seeks to highlight the most recent extent to which vegetative cover has changed in a 158,493-hectare (ha) top artisanal mining district in Ghana. The yearly three standard deviations of the Normalized Difference Vegetation Index (NDVI) was applied to assess the changes in vegetation. The NDVI was calculated on Harmonized Corpernicus Sentinel 2A/B imagery processed in Google Earth Engine from 01-December to 31-January of each dry season of 2019 to 2023. A vegetation loss rate of 1,464 ha/year, representing a 1.2% reduction in vegetation per year, was found. The analysis showed that the highest vegetation loss of 2,693 ha for a net loss of 2,346 ha was experienced in 2022–2023. The result of this study offers a rapid way to monitoring the fast-changing landscape and damaged farm lands in artisanal mining communities of southern Ghana. The results imply the need for intervention from the Ghanaian mining authorities to put measures in place to mitigate the negative effects of unregulated mining on the environment.