Français

Abstract

Wetlands in the Sahel play a very important role in sustaining both human and animal life. Lake Fitri, located in the heart of Chad, is one of these areas of attraction, following the climate and security crises that have affected the Sahelian countries. This attraction is creating pressures that will need to be monitored in order to limit the degradation of the area's natural resources. This study was initiated to assess land use dynamics over a 20-year period from 2002 to 2022 using Landsat and Sentinel-2 satellite images. The complexity of the environment led to the use of two methods of processing remote sensing images to map the different landscape units of the Fitri. These are Maximum Likelihood classification followed by digitisation to extract the areas of floodplain crops using GPS points collected in the field. In terms of dynamics, the study reveals that the natural environment has suffered more degradation in seven years, between 2015 and 2022, than in 13 years, between 2002 and 2015. The forest has recorded an average annual rate of spatial expansion of -8.79%. Meanwhile, crop areas and water bodies have been steadily increasing over the 20 years considered. The average annual rates are 3% for floodplain crops, 0.88% for rain-fed crops and 0.91% for water bodies. These results reveal a degraded natural environment estimated at 34%, but areas of cultivation and bodies of water have increased by 27% and 211% respectively over the 20 years considered.