Rebecca J. Howard Elijah W. Ramsey III Amina Rangoonwala 2020 <p>In response to a co-occurring non-native scale infestation and <i>Phragmites australis</i> dieback in southeast Louisiana, normalized difference vegetation index (NDVI) satellite mapping was implemented to track <i>P. australis</i> condition in the lower Mississippi River Delta. While the NDVI mapping successfully documented relative condition changes, identification of cause required a quantitative-biophysical metric directly related to <i>P. australis</i> marsh live vegetation proportion. During this study, a satellite mapping tool that quantified <i>P. australis</i> live fraction cover (LFC) magnitude was designed and implemented. The key to development of the quantitative LFC mapping was the field to satellite calibration design. The calibration of <i>P. australis</i> marsh LFC to optical satellite image data combined field and near-in-time satellite data collections in the fall of 2018 and summer of 2019. Basing the field-NDVI to field-LFC calibrations and the satellite-NDVI to field-NDVI calibrations on combined pre-senescence and peak-growth period data offers nearly year-round LFC mapping. The utility of the developed <i>P. australis</i> marsh LFC mapping tool was demonstrated by the creation of a yearly suite of Mississippi River Delta LFC status and change maps extending from 2009 to 2019. <i>P. australis</i> marsh LFC mapping relies on Sentinel-2 for current to future mapping and relies on Landsat for historical mapping.</p> application/pdf 10.3133/ofr20201131 en U.S. Geological Survey Mapping Phragmites australis live fractional cover in the lower Mississippi River Delta, Louisiana reports