Impact of Land Use Land Cover Change on Carbon Stocks and Forest Products-Related Livelihoods in the Central and Upper River Regions in The Gambia

Abstract

In the Central River Region (CRR) and Upper River Region (URR) in the Gambia, forests, woodlands, and agroforestry systems have long sustained local livelihoods. However, increasing agricultural expansion, changing land use practices, and climate variability threaten these ecosystems, with significant consequences for carbon storage and livelihood security. Given communities’ dependence on forest products for both subsistence and trade, ongoing LULC changes require a detailed scientific assessment. Understanding the dynamics of LULCC in these two regions and their implications for tree-based LULC and carbon stocks is essential for managing carbon emissions and enhancing ecosystem resilience to climate change. Since tree-based livelihoods share a common problem with climate change and climate variability, analyzing the two issues together provides a holistic way of addressing the concerns of LULCC and developing effective policies and strategies to slow and reverse the loss of tree cover. This study investigates land use and land cover (LULC) changes and their impact on aboveground carbon stocks and forest-dependent livelihoods in the CRR and URR from 2002 to 2024, with projections to 2034. Using Landsat imagery, supervised classification, and accuracy assessment in ArcGIS, the study identified four main LULC types: forest, grassland, cropland, and settlement. A stratified random sampling method was used, selecting 20 sampling points per LULC class in each region. Field data collection involved measuring tree diameter at breast height (DBH) with a diameter tape and tree height with a Sunnto clinometer within circular plots of 2,124 m². To assess livelihood dependence, a household survey was conducted with 396 respondents from both regions. Demographic data showed an average household size of 17.8 people, with ages ranging from 27 to 65 years and nearly equal gender representation. Multivariate probit regression indicated that gender significantly affected forest product use; men were more involved in using timber and thatch. Charcoal and firewood remained the dominant forest resources in both regions, though timber exploitation was higher in URR. The results show significant LULC transitions. Forest cover in CRR decreased by 95.2% to 310 hectares, and in URR by 85% to 127.8 hectares by 2024. Grasslands declined by 37.3% in CRR (to 165,729 hectares) and 40.6% in URR (to 116,763 hectares), mainly due to agricultural expansion. Croplands doubled in CRR (to 110,783 hectares) and increased by 82% in URR (to 74,794.68 hectares). Settlement areas grew by over 100% in both regions, reflecting rapid population growth and infrastructure development. Water bodies decreased by 12.3% in CRR and 19.4% in URR, likely due to upstream damming and irrigation pressures. Carbon stock analysis revealed notable forest carbon losses: in CRR from 11,059.72 tons (2002) to 23.49 tons (2034), and in URR from 378.89 tons to 12.32 tons. Grassland carbon decreased from 29,684.39 to 14,443.51 tons in CRR and from 14,162.60 to 6,983.52 tons in URR. Conversely, cropland and settlement carbon stocks increased significantly due to vegetation growth and urban greening. These changes highlight the profound effects of deforestation, urbanization, and agricultural expansion on regional carbon dynamics and ecosystem stability. The findings emphasize the urgent need for sustainable land management and climate-smart strategies. The study recommends combining satellite remote sensing with ground-based monitoring and predictive models to develop early warning systems. Promoting agroforestry and reforestation with native, multipurpose species can enhance tree cover and restore degraded lands while supporting local livelihoods.