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Mapping Phragmites australis live fractional cover in the lower Mississippi River Delta, Louisiana

January 27, 2021

In response to a co-occurring non-native scale infestation and Phragmites australis dieback in southeast Louisiana, normalized difference vegetation index (NDVI) satellite mapping was implemented to track P. australis 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 P. australis marsh live vegetation proportion. During this study, a satellite mapping tool that quantified P. australis 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 P. australis 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 P. australis 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. P. australis marsh LFC mapping relies on Sentinel-2 for current to future mapping and relies on Landsat for historical mapping.

Citation Information

Publication Year 2020
Title Mapping Phragmites australis live fractional cover in the lower Mississippi River Delta, Louisiana
DOI 10.3133/ofr20201131
Authors Amina Rangoonwala, Rebecca J. Howard, Elijah W. Ramsey III
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2020-1131
Index ID ofr20201131
Record Source USGS Publications Warehouse
USGS Organization Wetland and Aquatic Research Center