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Abstract Detail



Biogeography

Goodman, Arianna Camille [1], Douglas, Norman [1], Olvera, Hilda Flores [2], Ochoterena, Helga [3], Moore, Michael [4].

Lay of the Land(sat): Creating a Comprehensive Atlas of Chihuahuan Desert Gypsum using Multispectral Satellite Imagery and MaxEnt.

Edaphic endemic plants display complex but incompletely understood genetic patterns related to the geographic distribution of the soils on which they live. Over 200 species of plants in the Chihuahuan Desert region grow exclusively on island-like patches of gypsum (CaSO4·2H2O), but these gypsum outcrops have been poorly mapped. A comprehensive atlas of Chihuahuan Desert gypsum exposures would enable the identification of botanically unexplored gypsum and hence would be likely to lead to the discovery of undescribed endemic taxa, would facilitate studies of island biogeographic relationships in the Chihuahuan Desert gypsum flora, and would enable gypsum presence/absence to be included as an additional layer in species distribution modeling. Multispectral satellite imagery can be used to remotely sense soil types over large areas, but previous methods of identifying gypsum from publicly available imagery inadequately distinguish gypsum from other land cover types. For example, published methods using normalized difference ratios of two bands or other spectral indices often fail to identify hillside gypsum exposures and may incorrectly include non-gypseous soils on the shadowed north sides of hills. Furthermore, many image classification techniques involve more field surveying than would be feasible over a large scale or in remote desert locations. To address these problems, we have used maximum entropy modeling in conjunction with known localities of gypsum soils and Landsat 7 ETM+ imagery captured near the summer solstice to create large-scale, medium-resolution maps of gypsum throughout the Chihuahuan Desert region. Preliminary results suggest that this method produces more accurate and detailed probabilistic maps of gypseous soils than other methods, and may be useful for a variety of similar applications.

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Related Links:
Phylogenetics and phylogeography of Chihuahuan Desert gypsum endemics


1 - Oberlin College, Department of Biology, 119 Woodland St, Oberlin, OH, 44074, USA
2 - Instituto de Biologia, UNAM, Departamento de Botanica, Apartado Postal 70-233, Mexico, DF, C.P. 04510, Mexico
3 - Instituto De Biologia, UNAM, Depto BotŠnica-Apdo.Postal 70-367, Coyoacan, Mexico DF, N/A, 04510, Mexico
4 - Oberlin College, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, USA

Keywords:
Gypsum endemism
Chihuahuan Desert
remote sensing
Maxent.

Presentation Type: Oral Paper:Papers for Topics
Session: 50
Location: Magnolia/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 4:45 PM
Number: 50013
Abstract ID:718
Candidate for Awards:None


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