Mapping and quantifying biodiversity is key to effective conservation planning, yet gathering the necessary data can be costly and time-consuming. Conservationists and land managers therefore place a premium on methods, such as remote sensing, that yield tolerable estimates of biodiversity in the absence of exhaustive ground surveys. Bawa et al. have tested a method of estimating tree diversity from space. Their study, conducted in the Biligiri Rangaswamy hills in the Western Ghats, India, shows a strong and positive correlation between species richness and an index of green biomass—the Normalized Difference Vegetation Index (NDVI)—which can be assessed accurately using satellite imagery. This technique shows promise for estimating broad patterns of tree species diversity at the landscape scale in tropical forests, which may be crucial to identifying areas most in need of protection and where rapid destruction is underway. — AMS
