The Use of Landsat 7 Enhanced Thematic Mapper Plus for Mapping Leafy Spurge
Abstract
Euphorbia esulaL. (leafy spurge) is an invasive weed that is a major problem in much of the Upper Great Plains region, includingparts of Montana, South Dakota, North Dakota, Nebraska, and Wyoming. Infestations in North Dakota alone have had a seriouseconomic impact, estimated at $87 million annually in 1991, to the state’s wildlife, tourism, and agricultural economy. Leafyspurge degrades prairie and badland ecosystems by displacing native grasses and forbs. It is a major threat to protected ecosystemsin many national parks, national wild lands, and state recreational areas in the region. This study explores the use of Landsat 7Enhanced Thematic Mapper Plus (Landsat) imagery and derived products as a management tool for mapping leafy spurge inTheodore Roosevelt National Park, in southwestern North Dakota. An unsupervised clustering approach was used to map leafyspurge classes and resulted in overall classification accuracies of approximately 63%. The uses of Landsat imagery did not providethe accuracy required for detailed mapping of small patches of the weed. However, it demonstrated the potential for mappingbroad-scale (regional) leafy spurge occurrence. This paper offers recommendations on the suitability of Landsat imagery as a toolfor use by resource managers to map and monitor leafy spurge populations over large areas.