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Discrimination of wetland vegetation using close -range remote sensing
Abstract
The protection and conservation of sensitive environmental habitats has, in recent years, focused public attention on wetland ecosystems. Traditional methods of wetland assessment have been augmented through the use of remote sensing technologies. Remote sensing offers acquisition of copious amounts of data in short periods of time over land areas that might otherwise be inaccessible. The problem, however, from a remote sensing standpoint is that verification of wetland composition relies on accurate ground truth inventories. The establishment of a library containing unique spectral responses for obligates and facultative wetland plant species would provide baseline reference data for accurate assessment of wetland condition. This research focused on the spectral discrimination of five species of wetland plants that commonly coexist in temperate North American non-tidal wetlands. A specially designed wetland was constructed to closely approximate natural conditions, and was planted with monospecific stands of Typha angustifolia L., Nymphaea tuberosa Paine, Sparganium eurycarpum Engelm., Scirpus acutus Muhl., and Sagittaria latifolia Willd. Spectral data from multiple quadrats were collected through the use of a hyperspectral spectroradiometer operating at close range. The degree of similarity and difference within each monospecific stand was evaluated as was the difference and similarity among the species on each of nine dates throughout a single growing season. If identification of a unique spectral response (“signature”) was possible, the degree of variation within the stand must not exceed variation among the stands. A temporal investigation compared plant life cycles and physiology to spectral responses. Patterns of spectral variation clearly reflect seasonal lifecycle changes from juvenility through senescence, but do not exhibit spectral integrity that would consistently permit discrimination. Chlorophyll assays were compared to hyperspectral response to discern patterns of light absorption and reflectivity that might aid in the discrimination of species based on periods of increased or decreased chlorophyll production. Correlation between chlorophyll production and growth stages was observed but discrimination of the species based on those observations was not supported.
Subject Area
Geography|Botany|Environmental science|Remote sensing
Recommended Citation
DeMarey, Deborah Marie, "Discrimination of wetland vegetation using close -range remote sensing" (2002). ETD collection for University of Nebraska-Lincoln. AAI3055269.
https://digitalcommons.unl.edu/dissertations/AAI3055269