SUPERVISED CLASSIFICATION OF LANDSAT-7 IMAGERY FOR THE DETECTION OF PHRAGMITES AUSTRALIS IN BACK BAY NATIONAL WILDLIFE REFUGE

Phragmites australis, also known as common reed, is a major invasive species that inhabits much of the coastal marshland in the southeastern United States. P. australis out competes many native species of vegetation, thereby eradicating the habitat of many waterfowl and shore birds. Different management methods have been applied to eradicate this species, but none have been entirely effective. We examine the viability of using combined remote sensing and GIS techniques to obtain improved accuracy in the mapping and management of the spread of the reed. A GPS receiver was used within the study site of Back Bay National Wildlife Refuge to record the location of homogenous stands of common reed. The locations of these stands were superimposed on a multi-spectral Landsat-7 image for the purpose of extracting the spectral signature of P. australis. Using a supervised classification method, this signature was applied to satellite imagery of the entire study area. A multi-date analysis revealed dramatic spread of P. australis in areas of the refuge that are not subject to regular inspection and management.