Assessment of land cover change and changes in species composition and their environmental impacts at Oil industry Adar yale and Paloich area (Upper Nile State)

Abstract

The study was based on application of remote sensing techniques and GIS in combination with ground survey to detect forest cover changes in Upper Nile state. Assessment of forest changes was carried in Adar yale and Paloich area for the period 1994 to 2004, covering an area of (1918220) hectares. The remote sensing images based on Land Sat of type TM (Thematic Mapper). The images were analyzed using the software of (EARDAS IMAGINE 8.5) by analyzing light layers to identify and locate vegetation position based on supervised analysis that is after image improvement. The images were classified into classes representing ecological factors. This is done with the objective of determining and locating the extent of changes within the land contained in the study area. Images were combined to facilitate identification of changes at any time and location. The inventory work was done by measuring 190 sample plots using 0.1 ha. The inventory was conducted during 2004. Five land use categories were identified namely closed forests, open woodland, scattered trees and shrubs, agriculture land and bare land. The results indicated dynamic changes within and between the land cover categories. While open woodland area increased over the ten years, the closed forest and the scattered trees and shrubs categories area was decreased. This resulted in a net decrease of the area of forest and trees cover by (8432.1 ha ) equivalent to approximately 8% of the total area of forests and trees cover over ten years. Deforestation on the other hand resulted in land transfer from forested land categories to agriculture land use, constituting the main cause of forest cover decline. 11 The study indicates that application of remote sensing technology is an efficient method to be applied for detection of land use changes with ground data information and the compatibility of ground survey with remote sensing. Land use categorization using either of the two systems resulted in similar classes. In addition, ground survey facilitated understanding of the species regeneration potential. The three species: Acacia seyal, Acacia sengal and Balanites aegyptiaca appeared to be the common species and provide possibility for regeneration in degraded areas.