Estimating potential future (2030 and 2040) land use in the Bonsa catchment, Ghana, West Africa

Abstract

This study combined logistic regression, Markov chain and the Dyna-CLUE models to simulate land use patterns in the Bonsa catchment of Ghana, West Africa. Historical model validation produced Relative Operating Characteristics (ROC) statistics above 0.69; indicating a significant relationship between the driving factors and the land cover types, and overall accuracy of 71% as well as a Kappa statistic of 55%, indicating a moderate agreement between observed and simulated land uses. The statistics of the historical model were used to simulate three plausible future land use scenarios. The historical simulation revealed that increases in population density, proximity to roads and expansion of mines were the major drivers that significantly increased the probability of settlement expansion and deforestation. Simulations of future land use showed that settlement expansion and deforestation may increase by similar margins for all scenarios, but the increase in secondary forests may be higher for the economic growth and reforestation (EGR) scenario, compared to the economic growth (EG) and the business-as-usual (BAU) scenarios. The mining areas may double in the future for all the scenarios, but shrubs/farms may increase in the BAU scenario, but reduce marginally in the EG and the EGR scenarios. The results of this study can be used to support land use planning and evaluation of the impacts of different future development pathways.

Keywords: Bonsa catchment, deforestation, driving factors, Dyna-CLUE, land use, logistic regression, West Africa