Implications of climate, land-use and land-cover changes for pastoralism in eastern Sudan

摘要

This study examines the changes in climate and land-use/land-cover (LULC) along the livestock seasonal migration routes in El Gedaref region (eastern Sudan). Analysis of temperature, rainfall and aridity index (ratio of rainfall to reference evapotranspiration) data during 1941-2009 shows significant warming of the climate, increasing rainfall variability and seasonality, and intensifying aridity conditions during the start and end of the wet season. The somewhat recent enhancement of the overall (annual) rainfall has reflected only in the mid wet season and were caused by few very wet days, indicating increased rainfall concentration and possible risk of soil erosion. Such climatic alterations and variability have inherent implications for land-use and land-cover over the region. LULC changes were investigated using multi-temporal satellite imagery from three sites along the livestock routes. The major trends were drastic conversions of natural vegetation areas into large-scale mechanized agricultural land. This resulted in a progressive loss and degradation of grazing area in the entire region. Overall, the documented LULC changes may cause an irreversible loss of biodiversity and a depletion of other ecological services provided by natural vegetation. The results of this study provide useful information when seeking to resolve complex land-management issues.