Potential of colour-infrared digital camera imagery for inventory and mapping of alien plant invasions in South African shrublands

Australian Acacia plant species invade the fynbos biome of southern Africa and threaten the exceptionally high plant diversity in the Cape Floristic Region. We examine the utility of very-high spatial resolution (0.5 m) colour infrared (CIR) digital image data for discriminating Acacia species from native fynbos vegetation, other alien vegetation and bare ground. Image data were acquired at a very low cost with a single-chip, digital CIR camera mounted on a light aircraft. Shrub and tree features were uniquely identified using visual or computer-assisted interpretation. However, increases in dynamic range and accuracy of interpolation schemes for the single chip sensor will be required if semi-automatic and accurate mapping of invasive plants is to be achieved.