Accelerating land cover change in West Africa over four decades as population pressure increased

Rapid population growth in West Africa has exerted increasing pressures on land resources, leading to observable changes in the land cover and land use. However, spatially explicit and thematically detailed quantitative analyses of land cover change over long time periods and at regional scale have been lacking. Here we present a change intensity analysis of a Landsat-based, visually interpreted, multi-date (1975, 2000, 2013) land cover dataset of West Africa, stratified into five bioclimatic sub-regions. Change intensities accelerated over time and increased from the arid to the sub-humid sub-regions, as did population densities. The area occupied by human-dominated land cover categories more than doubled from 493,000km(2) in 1975 to 1,121,000km(2) in 2013. Land cover change intensities within 10km of new settlement locations exceeded the region-wide average by up to a factor of three, substantiating the significant role of population pressure as a force of change. The spatial patterns of the human footprint in West Africa, however, suggest that not only population pressure but also changing socioeconomic conditions and policies shape the complexity of land cover outcomes. Land cover change has accelerated in West Africa between 1975 and 2013 as human-dominated land area more than doubled, suggest analyses of Landsat based land cover data sets.