Spatio-Temporal Changes in Land Use Across South East Senatorial District of Rivers State

Abstract

Forests provide abundant resources for sustaining life forms and aid in carbon sequestration. Recently, due to urbanisation, forested areas are likely to be affected. To determine the nature of the forest, this study conducted a geospatial assessment of forest decline in the Southeast senatorial district of Rivers State, Nigeria. The study utilized satellite images (Landsat 7, 8, and Sentinel-2) downloaded from the USGS (United States Geological Survey). The downloaded imagery is used to carry out LULC (land use and land cover) analysis utilizing maximum likelihood supervised image classification techniques in ArcGIS 10.7 software, spanning the period from 1990 to 2020. The use of QGIS 3.40.1 software is employed to model and predict changes in land use by 2040. Additionally, the study employed the Fragstat software to determine the forested area and assess the level of forest decline in the study area. To further establish the authenticity of the results, the NDVI (Normalized Difference Vegetation Index) technique was used. The LULC result reveals that the built-up area increased from 9.42% in 1990 to 65.39% in 2020, while vegetation cover decreased from 63.40% to 21.21% between 1990 and 2020. Bare land, on the other hand, decreased from 18.40% to 5.64% from 1990 to 2020. The prediction analysis reveals that vegetation cover will decrease from 21.21% to 7.12% between 2020 and 2040, resulting in a 14.09% reduction. Meanwhile, built-up areas will increase from 65.39% to 77.78%, leading to a 12.39% increase. These changes are clear indications of forest decline. The result of the Fragstat analysis on the spatial extent of forested areas also reveals that the forested area, which was 11.30% in 1990, has decreased to 2.97% by 2020. The ANOVA (Analysis of variance) results indicate that there is a statistically significant variation with a p-value of 0.942152 0.05 in the land uses. The study concludes that farming and lumbering are the primary causes of forest decline. Instead, the study recommends implementing adequate policies to prevent further decline in the remaining forested areas. To this end, the study strongly recommends the practice of afforestation.