Diachronic study by spatial remote sensing of changes in plant cover in mining sites in the poura gold mine

During the decade 2010-2020, Burkina Faso experienced a significant mining boom. However, this phenomenon, although presenting enormous opportunities, is also a source of pollution and considerable negative impacts on vegetation. This study, carried out on the site of a former mine in Burkina Faso (Poura and surrounding artisanal sites) aims to evaluate the changes made in the vegetation under the influence of industrial and artisanal mining during the three phases: before, during and after mine operation. Landsat images from 1981, 2001 and 2021 were used to classify vegetation along with statistics on land use. The transition matrix has been created. The land use map for these three periods as well as the change map were produced. The results in the mine area indicate a reduction of forest land in favor of other occupations. The areas of wooded savannahs decreased from 1,285 ha in 1981 to 6 ha in 2001 and gallery forests from 51 ha to 39 ha. However, over the same period we are witnessing an improvement in shrub and grass savannahs of 5% of its initial surface area. The same goes for rainfed crops and agroforestry which increased by 20%. The period from 2001 to 2021 is marked by the closure of industrial mining and an increase in artisanal mines. This change in exploitation mode is marked by an increase in gallery forests and tree savannahs from 39 ha to 77 ha and from 6 ha to 57 ha respectively to the detriment of shrub and grass savannahs which lost 42% of their surface area. As for crops and habitats, they increased by 75% and 4% respectively. The typology of changes in land use showed a degradation of the plant cover due to industrial and artisanal exploitation. The industrialization of mining has had a negative impact on wooded areas, namely gallery forest and tree savannah, while artisanal mining has had a negative impact on shrub and grass savannahs. These degradations, whether industrial or artisanal, have converted land occupation units into fields and habitats. The degradation of the ecosystems of this area results from an action combined with factors linked to mining and the growth of fields to respond to the increase in the population coming from elsewhere in search of the precious stone. This activity must be supervised through training and awareness raising so that it can benefit the population, without having a negative impact on the environment.