Assessing Land Useland Cover Change And Its Effects On Soil Physicochemical Properties And Soil Macro-fauna Diversity In Shenkolla Watershed South Central Ethiopia
Land Use/Land Cover (LU/LC) change is one of the major global challenges induced byrnanthropogenic and natural factors. Understanding the scope of LU/LC changes, the driving forcesrnand consequences are crucially important for maintaining sustainable use of natural resource andrnpromoting sustainable agriculture. This study examined the land use/land cover changes that havernoccurred, during the 1973-2017 period and its driving forces. In addition, the study explored therneffects of the LU/LC changes and landscape positions on soil physicochemical properties, andrndiversity of soil invertebrate macro-fauna. Unsupervised and supervised classification techniquesrnwere employed to get thematic information from satellite imagery (1973, 1995 and 2017).rnHousehold survey, focus group discussion and key informant interview were also used torndetermine the drivers and consequences of this land use/land cover dynamics. Analysis of top soilrnsamples collected from four adjacent land use/land cover types (forest land, grazing land, croprncultivated outfields and homestead garden fields) all under lower landscape position wasrnconducted to determine the effects of LU/LC changes on soil physicochemical properties. Besides,rnanalysis of top soil samples collected from three landscape positions (upper, middle and lower)rneach landscape category having three land use types: forest, grazing land and cultivated land wasrnconducted to determine the effects of landscape positions on soil physicochemical properties. Thernsoil data was analyzed using ANOVA to determine variations in soil parameters among landscapernpositions and land use types and treatment means comparison was determined using the leastrnsignificant difference (LSD) at 0.05 level of significances. In order to evaluate the diversity of soilrninvertebrate macro fauna (SIMF) community eight parameters were measured: Shannon-Wienerrnindex, Simpson diversity index, Pielou’s measure of evenness, Margalef’s diversity index, thernNumber of Occurrence Index, Relative abundance, Density (individuals per square meter) of eachrntaxon and density of all SIMF and Bray-Curtis similarity index. SIMF data was further analysedrnusing ANOVA and a general linear model to determine variations and the influence of land userntypes on abundance and diversity of SIMF, respectively. The results showed that agricultural landrnsignificantly increased while area covered by forest, was diminished drastically over the past fourrnrndecades (1973-2017). Forest land was reduced from 29.51% in 1973 to 20.52% in 2017, whilernagricultural land use increased from 70.49% in 1973 to 79.48% in 2017. Agricultural expansion,rnregime change and social unrest, population pressure, shortage of farm land and biophysicalrnfactors were major driving forces of the LU/LC changes. Environmental implications such asrnclimate change, biodiversity loss, scarcity of basic forest products; habitat alteration, decline inrnquality and availability of water and crop yield reduction were consequences of the LU/LCrnchange. The results of soil analysis indicated that there were significant (p