Discriminating the Invasive Species, 'Lantana' using Vegetation Indices

Invasive species have been the focus of environmentalists due to their undesired impact on the ecosystem. Spread of Lantana (Lantana camara L.), an invasive plant species, has been found in diverse geophysical environments causing a threat to the native flora. Various eradication programmes have been attempted such as burning, chemical sprays, bio-control agents and physical plugging mechanism for removing such invasive species in India. The efforts and success of these programmes need to be augmented with a correct, quick and cost effective technique of mapping in order to locate them, understand their spatial extent and hence make the process comprehensive. Also Lantana's appearance as dense vegetation patches in remote sensing data causes problems for estimating forest canopy density. Remote sensing provides a possible solution in qualitatively and quantitatively evaluating terrestrial surface vegetation cover using spectral measure-ments. This research paper addresses issues and techniques adopted to detect and extract Lantana, and can be used for various applications in forestry as well as in eradication programmes. This study attempted to understand the appropriate band combination using Landsat data and generating vegetation indices in order to extract Lantana patches in an accurate manner. Twenty nine different vegetation indices were analyzed for their effectiveness in differentiating Lantana from other classes. The study showed that SAVI (Soil Adjusted Vegetation Index) is most favorable in discriminating Lantana followed by Perpendicular Vegetation Index-3 in the optimum bio-window (February to April).