Abstract
Lagos State, which is home to Lagos metropolis and the eighteenth largest urban agglomeration in 2018 in the world, has been characterized by rapid urbanization. An earlier study of the eastern segment of the state revealed dramatic urban growth in previously rural local councils where it replaced mostly ecological assets. For a statewide view of the landscape pattern changes, this study examined the western segment of the state to characterize the magnitude and trend of these changes. This was done with Landsat images for 1984, 2006 and 2015 along with ENVI 5.0 software and FRAGSTATS v.4.2 spatial pattern analysis program. Results show that cumulatively, the ecological assets, which comprised 75% of the area in 1984, have been whittled down to about 34% by 2015 having been lost through urban development. At the council level in 2015, the highest growth areas, in decreasing order of magnitude, were Alimosho, Badagry, Ojo and Amuwo Odofin local government areas. Both class and landscape-level metrics confirmed the dominance and fragmentation of the resultant landscape in 2015 by urban development. In 1984, vegetation dominated the landscape at 55% coverage and was the largest feature with the highest area-weighted contiguity or connectedness index. Thirty-one years later in 2015, built-up areas were the dominant patch with 54% coverage and the highest contiguity and area-weighted contiguity index, higher than vegetation. These findings have narrowed the information gap about the spatial and temporal changes in the ecological assets of the western segment of Lagos State as a result of rapid urban expansion.