Mapping Vegetation Degradation in Sudan Using NDVI data (1993-2003)

Desertification is a main environmental problem in Sudan. Due to the spatial nature of desertification, remote sensing (RS) and geographic information system (GIS) technologies are appropriate tools of providing practical and real time analysis capabilities, which could play an important role in assessing and monitoring desertification. The normalized difference vegetation index (NDVI) data source in the present study was the image archive covering East Africa between 1993 and 2003. The different change classes of NDVI values over the study period were calculated and mapped, using RS and GIS data. The results showed that the calculated areas of different change classes of NDVI, throughout the study period, reflected the variations in the vegetation cover in terms of decreased and increased areas. Most of the unchanged areas are related to desert areas in Northern Sudan, the permanent tree cover (woodland/forest) areas in Southern Sudan and rangelands. The analysis identified the following three areas where degradation has occurred: (1) Al Gedarif, Sennar, Gezira, White Nile, and Kassala states, which are the main rainfed mechanized crop production areas, (2) areas around major oil fields, (3) areas in Western Equatoria, Bahr Eljebel, Jonglei and South Darfur states around the main towns (Yambio, Yei, Juba, and Nyala). Area having increased vegetation cover over the last 10 years was 9.81% (244500.6 km²) of the total area of Sudan. The unchanged areas are related to desert areas and semi-arid areas in North Sudan where the primary perennial vegetation cover that have existed for decades and composed of slow growing Acacia species, while the unchanged areas in Southern Sudan (Wood land/Forest) the trend could be attributed inaccessibility for mechanized croplands agriculture, firewood collectors and charcoal production