Agricultural expansion into forest reserves in Zambia: a remote sensing approach

Forest reserves play an important role in the provision of ecosystem goods and services; however, these reserves are facing increasing anthropogenic impacts primarily because of agricultural activities. In sub-Saharan Africa, studies on understanding the extent and impacts of agricultural expansion into forest reserves are generally lacking. Thus, this study aimed to assess the extent of agricultural expansion into forest reserves in Zambia on a national scale between 2000 and 2018 and explores the drivers. We used a remote sensing approach by employing Google Earth Engine (GEE) and Random Forests classifier to map land cover changes at five-time steps: 2000, 2005, 2010, 2015 and 2018. Landsat images were used to map six land cover classes (forest, cropland, wetland, grassland, settlement, and water body) determined by the Intergovernmental Panel on Climate Change (IPCC). A social survey was also undertaken to understand the drivers of agricultural expansion into forest reserves at two study sited located in eastern and north-western part of Zambia. Based on the land cover maps which were produced with high accuracies ranging from 82% to 94%, the results indicated a general decline of 10% in forest area and an increase of 25% in cropland. Almost 50% of the forest reserves in Zambia are experiencing some form of encroachment, and 10% of these are heavily encroached (>90% loss). Local communities indicated that population growth, loss of soil fertility, high market demand for crops, land tenure system, and lack of law enforcement are the major drivers of agricultural expansion into forest reserves. This study highlights the need for policy marker to consider trade-offs in agricultural expansion and conservation of forest reserves relation to population growth. Enhancing sustainable agricultural practices and strengthening the implementation of different legislative frameworks is key in addressing the challenges of conservation, while enhancing food security.