Assessing and monitoring rangeland condition in extensive pastoral regions using satellite remote sensing and GIS techniques: An application to the Ceres Karoo region of South Africa

Abstract

The purpose of this paper is to describe the use of satellite remote sensing and GIS techniques in applying a localised range condition assessment methodology based on fence‐line contrasts. The approach was to compute six dissimilarity indices for data on vegetation cover and composition from paired, site‐specific surveys across farm boundaries. Fence‐lines were buffered using the ARC/INFO GIS, and a soil adjusted vegetation index (SAVI) was computed from Landsat Thematic Mapper data of the area. Two dissimilarity indices were computed for paired pixel sets of SAVI values and statistically analysed for differences between their means. These satellite‐derived dissimilarity values were correlated with the indices from the rangeland survey data to test whether the satellite measures could be used to identify and quantify artificial boundary events. The results indicate that it is feasible to detect and quantify fence‐line differences in range condition with the use of satellite imagery that is registered to other relevant geographical data.