Land use/cover change and urban sustainability in a medium-sized city

This study examined the trend in urban growth and vegetation loss and the implication of this on the sustainability of medium-sized cities, using Osogbo, south-west Nigeria as a case. Using multi-temporal Landsat™ images that span 30 years (1986 to 2016), the study employed supervised classification to categorise the land cover into the built-up area, vegetation and water bodies. Findings revealed that the city grew axially along major transportation corridors in the early stage but experienced in-filling, densification and radial outward growth subsequently. The built-up area increased at annual rate of 14.7%, more than the population growth rate of 2.2% while vegetation cover and water bodies recorded an annual change of ‒2.5% and ‒3.5% respectively. Rapid city growth and the resultant land use/cover conversion contribute to the depletion of wetlands and vegetation, thereby constituting a threat to sustainable urban development. Controlled urbanisation is suggested as a panacea to the unsustainable urban expansion which threatens the city's ecological equilibrium.