Finding Leafy Spurge with Remote Sensing
Leafy spurge is an invasive, noxious weed in the upper Great Plains of the United States that destroys the land's potential forage for wildlife and livestock. Determining the location and abundance of leafy spurge with remote sensing will help prioritize areas for treatment with biological and conventional control measures. A conspicuous feature of leafy spurge is the dense yellow-green bracts on flowering shoots, which appear in late June and early July. We found that these bracts are detectable using an advanced hyperspectral sensor, NASA's Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS). By comparing the reflectance spectrum of a pixel with the spectral signature of flowering leafy spurge, we can determine the amount of leafy spurge in that pixel. Below-left is an AVIRIS image of Devils Tower National Monument in northeastern Wyoming (center) along the Belle Fourche River (right). Below right is the resulting analysis with yellow representing 50% or greater leafy spurge cover, green being from 30 to 50% spurge, brown being from 10 to 30% leafy spurge cover, and black being less than 10% leafy spurge cover. Field work shows this method is over 95% accurate in locating leafy spurge.
 
Contact:
E. Raymond Hunt, Jr. erhunt@hydrolab.arsusda.gov
Publication:
Parker-Williams, A., and Hunt, E. R. Jr., Accuracy assessment of leafy spurge detection with hyperspectral remote sensing, Journal of Range Management 57:106-112, 2004.
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