Monitoring Land Cover Changes in Shasha Forest Reserve, Osun State, Nigeria (1987–2023) Using Remote Sensing and GIS Techniques

Forests in Nigeria continue to face substantial pressure from agriculture, population growth, logging, and other forms of land conversion. Reliable information on land use and land cover dynamics is therefore essential for sustainable forest management and biodiversity conservation. This study assessed land cover changes within Shasha Forest Reserve, Osun State, Nigeria, over 36 years using Landsat satellite imagery acquired in 1987, 2002, and 2023. Landsat TM, ETM+, and OLI imagery obtained from the United States Geological Survey was processed and classified using a supervised maximum-likelihood classification approach. Four land cover categories were identified as dense forest, built-up area, sparse vegetation, and water bodies. Post-classification change-detection techniques were applied to quantify the magnitude and rate of change between the study periods. The findings showed a decline in dense forest cover throughout the study period. Dense forest decreased from 185.13 km² in 1987 to 152.19 km² in 2023, representing a loss of 14.06%. Built-up area increased substantially from 18.61 km² in 1987 to 49.18 km² in 2023. Sparse vegetation fluctuated during the study period, while water bodies declined by 2023. The observed changes indicate anthropogenic pressure on the reserve, particularly from settlement increase and land conversion activities. The usefulness of remote sensing and GIS techniques for long-term forest monitoring displayed in the study highlights the need for improved conservation measures and sustainable land use management practices within Shasha Forest Reserve.