Spectral and physiological uniqueness of perennial pepperweed (Lepidium latifolium)

Abstract

Abstract Perennial pepperweed is an aggressive, exotic weed invading wetland and riparian areas in California, including the San Francisco Bay/Sacramento–San Joaquin Delta Estuary. Effective management will require detailed and accurate maps of its distribution. Remote sensing technologies offer the capability to map weed species over broad areas and with rapid return intervals. As a first step in assessing the potential to map perennial pepperweed with hyperspectral remote sensing data, this study determined its spectral uniqueness relative to co-occurring species. Spectral measurements were conducted during summer drought conditions in the Sacramento–San Joaquin Delta region. Reflectance spectra of perennial pepperweed and seven co-occurring species were collected with a portable spectrometer. Nineteen physiological indexes were calculated from the reflectance data. Physiological indexes are sensitive to narrow spectral features and encapsulate reflectance information in ecologically relevant ways. Clas...