Spatio-Temporal Dynamics of the Noun Floodplain (Cameroon) Using Remote Sensing

Abstract

In Cameroon, the pressure on wetlands appears to be increasing, leading to desertification and land degradation. This study aims to characterize the spatial and temporal dynamics of land cover in the Noun floodplain in Cameroon using multi-date satellite data. To achieve this, the methodology consisted in using remote sensing and geographical information's systems techniques to identify spatial units and detect changes over a 22-year period (1999 to 2021). The land cover maps were produced from an unsupervised classification with maximum likelihood. The results identified eight classes: herbaceous savannahs with shrubs, forest galleries, fields and plantations, herbaceous tan, young fallows, mineralized and built-up soils, bare soils and surface waters. It appears that in 1999, the landscape was dominated by natural vegetation (72.6%) located from north to south of the Noun plain. However, since 2004, the landscape has been dominated by agricultural areas (56.8%). Natural formations have been progressively reduced in space over time. The evolution of the Noun floodplain landscape reveals that 14.3% of the space has remained stable. These are fields and plantations, young fallows, mineralized soils and surface water. This space has not migrated to other classes. While about 73.9% of the area has moved to higher classes, of which 35.6% to herbaceous tans and 26% to fields and plantations. On the other hand, 72.6% of the area (herbaceous savannahs and forests gallery) has been heavily degraded. These results show that the landscape of the Noun floodplain is marked by a progressive agricultural extension, which would be at the origin of the land degradation.