Can early season Landsat images improve locust habitat monitoring in the Amudarya River Delta of Uzbekistan ?

Reed (Phragmites australis) stands of the Amudarya River delta south of the Aral Sea in Uzbekistan serve as permanent breeding areas of the Asian migratory locust (Locusta migratoria migratoria). Locust swarms threaten agricultural fields adjacent to the delta. Every year, specialists from the Uzbekistan Plant Protection Service attempt to survey this vast delta to assess growth of reed which provides a habitat for locust nymphal infestations. Inferences regarding locust distribution are drawn and recommendations for chemical treatments made, based on very limited samples. This often results in blanketing wetland areas with broad-spectrum insecticides, thus harming nontarget fauna. In this study, early season Landsat data, coinciding with the locust survey planning stage, were used to generate a map of potential locust habitat. Using iterative image classification and reference data, a reed distribution map was generated with an overall accuracy of 74% (kappa agreement = 0.686). Landsat data were able to correctly identify 87% of the reed beds, but had some difficulty separating other vegetation when it was mixed with reeds. Minimizing these errors would improve the overall accuracy; however, this does not diminish the utility of this tool for locust habitat monitoring. Incorporation of remotely sensed data into current survey practices could provide precise information about the spatial distribution of reeds. Plant protection specialists could then use this to optimize planning and execution of antilocust treatments, reducing the negative environmental impact of these.