Land-Use and Land-Cover Change and its Association with Land Degradation in Njaluahun Chiefdom, Eastern Sierra Leone: A Multi-Temporal Landsat Assessment
Saffa Lansana *
Institute of Geography and Development Studies, School of Environmental Sciences, Njala University, Njala Campus, PMB, Freetown, Sierra Leone.
Victor Tamba Simbay Kabba
Institute of Geography and Development Studies, School of Environmental Sciences, Njala University, Njala Campus, PMB, Freetown, Sierra Leone and Department of Agribusiness Management, School of Agriculture and Food Sciences, Njala University, Njala Campus, Freetown, Sierra Leone.
Lamin R. Mansaray
Institute of Geography and Development Studies, School of Environmental Sciences, Njala University, Njala Campus, PMB, Freetown, Sierra Leone and Department of Agribusiness Management, School of Agriculture and Food Sciences, Njala University, Njala Campus, Freetown, Sierra Leone.
Peter Makieu
Institute of Geography and Development Studies, School of Environmental Sciences, Njala University, Njala Campus, PMB, Freetown, Sierra Leone and Department of Agribusiness Management, School of Agriculture and Food Sciences, Njala University, Njala Campus, Freetown, Sierra Leone.
*Author to whom correspondence should be addressed.
Abstract
Land-use and land-cover (LULC) change is closely associated with land degradation in rural landscapes of Sierra Leone, yet long-term chiefdom-scale assessments remain limited. This study assessed multi-decadal LULC change in Njaluahun Chiefdom, Kailahun District, using Landsat imagery from 1991, 2001, 2010 and 2021 and examined local perceptions of land degradation through household surveys. Supervised classification distinguished trees/forest, crop/fallow, wetland, open water and built/barren classes within the official 256 km² chiefdom area. Because unclassified/cloud/no-data pixels increased from 0.0 km² in 1991 to 40.0 km² in 2021, trends were also evaluated as percentages of classified pixels. Between 1991 and 2021, trees/forest declined from 67.0 to 21.3 km², wetlands from 54.1 to 16.1 km², and open water from 42.9 to 18.8 km². Over the same period, crop/fallow increased from 40.4 to 78.4 km² and built/barren from 51.6 to 81.4 km². Forest loss was most rapid after 2001. Household interviews with 200 long-term residents indicated that slash-and-burn upland cultivation, over-cropping, deforestation and small-scale mining were perceived as important drivers of land degradation, while knowledge of sustainable management practices remained limited. The combined remote-sensing and community evidence identifies consistent landscape-change patterns while supporting association rather than quantitative causal attribution to individual livelihood activities, thereby supporting more targeted land-use planning decisions.
Keywords: Land-use/land-cover change, land degradation, Landsat, Njaluahun, Sierra Leone, slash-and-burn