Satellite-derived Vegetation Indices Applied to Semi-arid Shrublands in Australia

摘要

Vegetation indices calculated from satellite sensor data are routinely used to map and monitor vegetated areas on regional, continental and global scales. In the Australian semi-arid region, however, the most commonly used vegetation indices are shown to be inappropriate. In this study, a semi-arid shrubland in western New South Wales was used to test a number of vegetation indices developed from Landsat Thematic Mapper sensor data. Vegetation cover varied from a mean of 22 per cent in mid-summer to a mean of 78 per cent in mid-winter. There was no significant relationship between the Normalised Difference Vegetation Index (NDVI) and summer vegetation cover, though there was a significant relationship with total vegetation cover in winter. The Stress Related Vegetation Index, which utilises both near and middle infrared wavelengths, related to total vegetation cover in both winter and summer. The Australian Arid Rangelands Vegetation Index related to the total cover of saltbush shrubs in winter and to total percent cover in summer. The Landsat Thematic Mapper vegetation indices most useful for monitoring vegetation in this semi-arid region are the Stress Related Index and the Australian Arid Rangelands Index.