Urban growth assessment and its impact on deforestation in makurdi metropolis, Nigeria

Abstract

There has been a rapid growth of urban areas across the globe since 1950s with the majority of world population living in urban areas, in search of better job opportunities and services. This trend of transition from rural to urban is expected to continue to rise and government in developing countries are likely going to face more challenges in different sectors, necessitating the need of understanding the spatial pattern of the growth and its impact on the environment for an effective urban planning. The study was aimed at modelling urban growth in Makurdi and the impacts on deforestation The study covered a period of 30 years; from 1987 to 2017, and the major transitions to urban were modelled to predict the future scenarios in 2030. Three Landsat satellite images of 1987, 2007 and 2017 were classified using maximum likelihood classifier in Idrisi Selva to detect the land cover changes and a classification overall accuracy was 88.78%, 82.7% and 80.52% for 1987, 2007 and 2017 maps while Kappa index of agreement (KIA) was 0.86. 0.79 And 0.76 for the same period. The result of the classification revealed that between 1987 and 2017, urban area in Makurdi increased to the tune of 12125ha (422.33%) at the rate of 14.07% while forest declined by 11742ha (52.21%) at the rate of 1.74%. Physical and proximity factors such as distance from urban areas, distance from roads, distance from rivers, elevation, slope, population density, evidence likelihood of transition and distance from railways were identified as major factors driving urban growth in the area. It was found that evidence likelihood of transition and the distance from urban areas and distance from railway were the most important factors shaping urban growth in the area. Thereafter, a Multilayer Perceptron Markov (MLP-Markov) model was used to model transition potentials of various LULC types to predict future changes. The models had a reliability of 81.4%, after validation. The results of the prediction show that urban area will increase from 17.95% to 20.81% while forest will decline from 12.85% to 10.25% during the period and that urban area is the third largest contributor to deforestation. It reveals that Makurdi will grow at the rate of 2.86. Analysis of the prediction revealed that the rate of urban growth will continue and would certainly threaten forest areas in the area. Makurdi stands the risk of extreme deforestation if appropriate measures are not taken.