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Remote sensing of biomass of selected emergent aquatic macrophytes

Steven Lee Payton, University of Nebraska - Lincoln

Abstract

This research focussed on remote sensing of biomass of three locally common emergent freshwater plant species at close-range in a controlled, experimental setting as well as at satellite altitude in a natural wetland. Close-range hyperspectral reflectance and biomass data were collected over cultured plots of cattail and reed. These species were characterized with respect to spectral separability as well as to the relationship between spectra and biomass. Biomass sampling in a natural freshwater wetland in the Nebraska Sandhills was conducted with near-concurrent satellite imagery to investigate the relationship of biomass to Landsat Thematic Mapper (TM) reflectance and ERS-1 Synthetic Aperture Radar (SAR) backscatter. Two TM images and five ERS-1 SAR images were evaluated with regard to estimating aboveground vegetative biomass of reed, cattail, and bulrush. ^ Results indicate that significant differences between reed and cattail can be detected on various dates and wavelengths using close-range optical data at hyperspectral resolution and at simulated TM and MSS spectral bandwidths. The magnitudes of the detected differences were greatest early in the growing season (before July 12) and the greatest differences were located in the near infrared wavelengths. Further, results showed that close range, near-infrared reflectance is linearly related to biomass of reed and cattail, though estimation of reed biomass is possible only before August 23. Strong relationships between biomass and close-range near-infrared reflectance were observed for both species (r2 > 0.90) though the relationship with reed was only valid before August 8. ^ The results regarding the satellite imagery of the natural wetland indicated much weaker relationships with biomass (r2 < 0.64). A significant correlation between TM near-infrared reflectance and biomass of Scirpus as well as between the TM vegetation index NDGI and biomass of Typha was detected on the early TM image (6/14/95). A significant correlation between ERS-1 SAR radar and biomass was identified for Phragmites (9/16/95) and Typha (6/3/95). ^

Subject Area

Geophysics

Recommended Citation

Payton, Steven Lee, "Remote sensing of biomass of selected emergent aquatic macrophytes" (2001). ETD collection for University of Nebraska - Lincoln. AAI3016322.
http://digitalcommons.unl.edu/dissertations/AAI3016322

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