Satellite images indicate vegetation degradation due to invasive herbivores in the Andaman Islands.

Recent studies have documented changes in vegetation cover due to invasive herbivores in the Andaman Islands. In this study we demonstrate that the change is large enough and rapid enough to be detected by remotely sensed data. Using the freely available Normalised Difference Vegetation Index (NDVI) imagery, we examined changes in vegetation cover due to the presence of invasive herbivores in the Andaman Islands. Two time-periods were analysed using different types of imageries. Changes between 1985 and 1995 and also between 2001 and 2005 across four sites with different combinations of introduced chital (spotted deer) and elephants were examined. Results indicate that areas with deer have faster rates of degradation than those without them. The maximum rate of degradation occurred at sites with both elephants and deer, and the minimum where neither of the two animal species occurred. Besides wild pig, all the other herbivores on the islands are invasive, and there is a need to eliminate these invasive herbivores in the islands.