An assessment of Spatio-temporal Forest covers Changes Impacts on Land Degradation and Its Consequences in Gida Ayana District, Ethiopia Using Geoinformatics Techniques

Abstract

The study have been examined the impact of spatio-temporal forest cover change on land degradation and its consequences using geospatial technology. The multi-temporal satellite images of Landsat TM of 1985, Landsat ETM + of 2000, and Landsat OLI/TIR of 2020 with spatial resolution of 30 meters have been used to map potential and actual land degradation. Major biophysical factors (vegetation condition, rainfall erosivity, soil erodibility, slope factor, and population density) for land degradation were compiled and analyzed for final modeling. Vegetation condition have been computed from Land Use Land Cover (LULC) and NDVI. LULC have been classified into five LULC classes i.e., grassland, farmland, forest, wetland and settlement, while NDVI classes were very low, low, medium, high, very high vegetation cover. Probability rank weighted approaches have been applied in this study during the overlay analysis in ArcGIS environment. The results have shown that there was major expansion of farmland areas in the last 35 years of analysis period i.e., from 52.10% in 1985 to 53.87% in 2000 and 61.47% in 2020, while there was a high degradation in the area of forest land in 35 years of analysis period i.e., from 34.36% in 1985 to 32% in 2000 and 21.68% in 2020. The actual and potential land degradation values in each year shows that there was significant increment in area of degradation (very high degradation was 74,827 ha in 1985, 80,956 ha in 2000, 91,483 ha in 2020 for actual one, two, and three respectively and very high degradation 79,376 ha in 1985, 82,320 ha in 2000 and 83,431 ha in 2020 for potential one, two and three respectively. The above time series land degradation increment trend in the study area for actual and potential was due to high deforestation, intensive agricultural expansion, and increment of the human and livestock population in the study period. Direct beneficiaries of this study will include recourses manager, regional planner as well as scientific community.