Land Use and Land Cover changes in Lake Bosumtwi Watershed, Ghana (West Africa)

Abstract

Lake Bosumtwi is the only natural lake in Ghana, the deepest in West Africa, and among the UNESCO world biosphere reserves. Fisheries resources and tourism activities around the lake generate income to support about 50,000 rural inhabitants. The lake's catchment has experienced significant land use, and land cover (LULC) changes due to livelihood diversification in response to ecosystem changes and fisheries decline due to climate warming. We assessed LULC changes between 1986 and 2018 in the lake's catchment using GIS and remote sensing techniques. Satellite imageries from Landsat TM, ETM+, and Sentinel 2A for the periods 1986, 2002, 2007, and 2018 respectively were acquired. A supervised maximum likelihood classification analysis revealed that the lake's surface area had shrunk by 3.7%. In comparison, 22.6% of closed forests and open forests have transitioned to farmlands, built-up areas, and bare lands. Farmlands and built-up areas were increasing at a rate of 5.2% and 5.4% per annum respectively, while closed forest, open forest, and the lake's surface area was reduced by 1.3%, 0.8%, and 0.1% respectively from 1986 to 2018. Management interventions are urgently required to stop the of deforestation if the remaining remnant forestis to be preserved. Data on the identified drivers of LULC changes in the lake's watershed derived from this study would serve as a reference for modelling future LULC changes for the protection of vulnerable areas to help build the resilience of the lake to climate change and anthropogenic pressures.