Rangelands in Zimbabwe’s initial resettlement schemes: Spatial and temporal change analyses

Abstract

Change in size and extent of cultivation and vegetation cover was analysed in three villages of an initial resettlement scheme in Zimbabwe using change detection depicted on serial aerial photographs taken at eight-year intervals from inception in 1981 to 1997. A geographic information system was used as an analytical tool. Interpretations were done using aerial photographs and 1995 Spot Images. The spot images were geo-referenced to Universal Transverse Mercator (UTM) coordinate system to ensure continuity of features. All images were enhanced using TNTmips to come up with clearer images. Aerial photographs for the three selected villages were scanned and geo-referenced and then exported to ARC VIEW 3.2 for on-screen digitising of land parcels as cultivated and vegetation theme layers. Overlay and spatial analysis were also done in ARC VIEW 3.2 for change detection. Results showed an average increase in size of cultivated areas by 281% between 1981 and 1997 and a increase of 52% between 1989 and 1997 in the three villages. Rangelands declined by a mean 42% during 1981 and 1997. There was a shift in land-use in 1987/8, which exaggerated cultivated areas due to fuzzy classification of land reverting to grazing areas by 1989. This shift in cultivation sites was adequately captured on overlaid aerial photographs for each of the three villages. It was concluded that spatial and temporal changes occurred in resettlement schemes rangelands and were due to the actions of resettled farmers. Keywords: Resettlement schemes, change detection, spatial analysis.