Remote sensing of the effects of irrigation activities on vegetation health in ephemeral wetlands of semi-arid Australia

The ephemeral wetlands of semi-arid Australia provide important habitats for many species and play a significant role in the hydrological and biological regimes of these environments. As most inland wetlands owe their existence to unregulated cycles of flooding and drying, many wetlands are now being forced into decline through flow regulation associated with irrigation for large, highly productive agricultural enterprises. Time series of JERS-1 optical and radar imagery and Landsat TM imagery were used to determine the potential for employing various vegetation species as indicators of wetland decline in the Macquarie Marshes of central western New South Wales. River red gum, Water couch, Cumbungi and Common reed species could be detected at sufficient spatial and spectral resolution to be mappable from satellite imagery, and health gradients were detectable in certain species. The development of these techniques offers good potential to facilitate monitoring of wetland health and assist in management decisions regarding flood control within inland wetlands.