Geospatial Analysis of Agricultural Encroachment on Natural Forest in Ife South Local Government Area, Osun State, Nigeria

Abstract

This study examines the spatio-temporal dynamics of agricultural encroachment on natural forests in Ife South Local Government Area, Osun State, South-Western Nigeria. Over the past two decades (2002 – 2022), the region has witnessed significant land use changes, driven by economic transformation and population growth, leading to the conversion of forested areas for cultivation. The study utilized Landsat imageries for 2002 (ETM+), 2015, and 2022 (OLI/TIRS) were acquired from the United States Geological Survey (USGS) at a 30-meter spatial resolution. The images were processed and classified using ArcGIS 10.8 and ERDAS Imagine 2015. A supervised classification was performed to quantify land use/land cover changes. Supplementing the geospatial analysis, in-depth interviews were also conducted in selected communities within the study area to gauge perceptions. The findings reveal a complex pattern of change: while natural vegetation showed a net increase of 28.13% over the 20-year period, it experienced a significant decline of 39% between 2002 and 2015 before recovering. Cultivated land and plantations decreased by 28.78% and 63.31% respectively, whereas built-up areas expanded dramatically by 138.62%. Qualitative data identified agriculture as the primary driver of forest loss (90% of respondents), leading to negative impacts on livelihoods, including reduced crop yields and loss of forest benefits, as well as environmental degradation such as reduced air quality and land degradation. The study recommends an integrated approach involving sustainable land-use planning, agroforestry, community participation in forest management, and strengthened law enforcement to mitigate encroachment and achieve a balance between agricultural development and environmental conservation.