MODELLING LAND USE AND LAND COVER DYNAMICS ON THE PHYSICAL ENVIRONMENT OF BENUE STATE, NIGERIA

Abstract

The study was aimed at modelling urban growth in Benue State and the impacts on vegetation loss with a view to providing the much needed information to guide urban planning into the 2030s. The emphasis was on Benue State and four selected urban areas of Makurdi, Gboko, Otukpo and Katsina-Ala in the state and x-raying their impact 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 accuracy in the range of 80.77% to 91.6% for the three epoch was achieved . The result of the classification revealed that between 1987 and 2017, urban area in Benue State gained 59081ha (147.31%) at the rate of 4.91%per year while forest lost 465186ha (45.1%) at the rate of 1.5% per year. In Makurdi, urban area increased to 12125ha (422.33%) at the rate of 14.07% while forest declined by 11742ha (52.21%) at the rate of 1.74%. The result for Gboko, Otukpo and Katsina-Ala revealed similar trends. 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 Benue State. It was found that evidence likelihood of transition and the distance from urban areas and elevation were the most important drivers of urban growth in Benue State. 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 78.5%, 81.4%, 83%, 81.7% and 85.8% after validation for Benue State, Makurdi, Gboko, Otukpo and Katsina-Ala respectively. The results of the prediction show that Benue urban area will increase from 3.17% to 3.91% between 2017 and 2030 while forest will decline from 18.09% to 16.7%. In Makurdi, urban area will increase from 17.95% to 20.81% while forest will decline from 12.85% to 10.25% during the period. Gboko will see urban area increase from 8.65% to 9.46% but forest will decrease from 8.71% to 7.43%. Otukpo will experience increase in urban area from 11.59% to 12.6% and forest will decline from 12.54% to 10.98%.Katsina-Ala will have urban area increase from 5.92% to 6.35% with forest declining from 10.8% to 9.46%. It reveals that Makurdi, Gboko, Otukpo and Katsina-Ala will grow at the rate of 2.86%, 0.81%,1.01%, and 0.46% respectively. Analysis of the prediction revealed that the rate of urban growth will continue and would certainly threaten forest areas in Benue State. The study provided a very valuable insight not only on the extent of future growth of urban areas but most importantly on its spatial pattern. The findings of this research should be used in maintaining sustainable urban growth by balancing between population increase and urban expansions.