An Image-Based Diversity Index For Assessing Land Degradation in an Arid Environment in South Australia

Abstract

One of the major indirect effects of artificial watering points in a grazed landscape is the development around them of a zone of extreme degradation called a piosphere. To investigate the degradation status of such zone in an arid environment in South Australia, the Moving Standard Deviation Index (MSDI) was applied to Landsat TM band 3 data. We found that watering points had significantly higher MSDI values (p <0.001) than reference areas (non-degraded areas. The results of two vegetation indices, the Normalized Difference Vegetation Index (NDVI) and Perpendicular Distances vegetation index (PD54), which were used as reference indices showed that The PD54 was more appropriate than NDVI in this arid environment. Piospheres were found to be more heterogeneous (high MSDI values) than non-degraded areas and heterogeneity decreased by increasing distance from water points. This study confirms that MSDI can be used as an appropriate adjunct to PD54 for land degradation assessment in arid rangelands of South Australia, which are naturally heterogeneous.