ANALYSIS OF CHANGES IN LANDUSE AND LANDCOVER IN THE SUBURBAN AREAS OF IBADAN, NIGERIA.

OLAYIWOLA, A.M.* AND FAKAYODE, O.

This study analysed the spatial changes in landuse and landcover in the suburban areas of Ibadan, Nigeria between 1986 and 2017. Data were sourced from the National Population Commission (NPC) and Landsat imageries (Landsat 5 MSS/TM, 1986; Landsat 7 ETM+, 2002; and Landsat 8 OLI/TIRS, 2017). Administrative maps of the area were scanned, georeferenced and digitized in ArcGIS environment. Following Anderson’s modified version of supervised classification scheme, the imageries were classified into four landuse/landcover classes: built-up, vegetation, exposed surfaces and water bodies. The changes in landuse/landcover for the area were determined by pixel labelling. The period of change analysis was divided into two epochs; 1986-2002 and 2002-2017. Furthermore, a transition probability matrix of landuse change was developed and utilized for assessing the probabilities of other landuses changing to built-up in Markov chain detection method with Cellular Automata. Results of accuracy assessment indicate good image classification (1986, 99.98%; 2002, 99.62%; 2017, 99.21%). Also, results indicate that in the first epoch of study the greatest loss was from vegetation, while very little portions of water bodies and exposed surfaces were converted to other uses. In the second epoch, much of the exposed surface and vegetation were transformed into built-up, while there was no significant transition in the water bodies. Results indicate a future probability of exposed surface and water bodies changing to built-up as higher than that of vegetation. The study concluded that heterogeneous and haphazard land development in the study area was borne out of uncontrolled urban growth. Thus, the study recommends the need for the town planning authorities to be proactive in their duties in order to forestall imminent dangers of shortage of food supply as well as slum and sprawl formation.

Key words: Landuse/cover changes, Markov chain, Physical expansion, Suburban, Transition probability, Trend analysis.