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dc.contributor.authorDavidson, Eric A.  Concept link
dc.contributor.authorAsner, Gregory P.  Concept link
dc.contributor.authorStone, Thomas A.  Concept link
dc.contributor.authorNeill, Christopher  Concept link
dc.contributor.authorFigueiredo, Ricardo O.  Concept link
dc.date.accessioned2010-05-27T15:09:49Z
dc.date.available2010-05-27T15:09:49Z
dc.date.issued2008-07-23
dc.identifier.citationJournal of Geophysical Research 113 (2008): G00B03en_US
dc.identifier.urihttps://hdl.handle.net/1912/3545
dc.descriptionAuthor Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): G00B03, doi:10.1029/2007JG000622.en_US
dc.description.abstractDegradation of cattle pastures is a management concern that influences future land use in Amazonia. However, “degradation” is poorly defined and has different meanings for ranchers, ecologists, and policy makers. Here we analyze pasture degradation using objective scalars of photosynthetic vegetation (PV), nonphotosynthetic vegetation (NPV), and exposed soil (S) derived from Landsat imagery. A general, probabilistic spectral mixture model decomposed satellite spectral reflectance measurements into subpixel estimates of PV, NPV, and S covers at ranches in western and eastern Amazonia. Most pasture management units at all ranches fell along a single line of decreasing PV with increasing NPV and S, which could be considered a degradation continuum. The ranch with the highest stocking densities and most intensive management had greater NPV and S than a less intensively managed ranch. The number of liming, herbiciding, and disking treatments applied to each pasture management unit was positively correlated with NPV and negatively correlated with PV. Although these objective scalars revealed signs of degradation, intensive management kept exposed soil to <40% cover and maintained economically viable cattle production over several decades. In ranches with few management inputs, the high PV cover in young pastures declined with increasing pasture age, while NPV and S increased, even where grazing intensity was low. Both highly productive pastures and vigorous regrowth of native vegetation cause high PV values. Analysis of spectral properties holds promise for identifying areas where grazing intensity has exceeded management inputs, thus increasing coverage of senescent foliage and exposed soil.en_US
dc.description.sponsorshipThis research was supported by grant NNG06GE88A of NASA’s Terrestrial Ecology Program as part of the Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2007JG000622
dc.subjectAmazonen_US
dc.subjectPasturesen_US
dc.subjectNova Vidaen_US
dc.subjectParagominasen_US
dc.subjectDegradationen_US
dc.titleObjective indicators of pasture degradation from spectral mixture analysis of Landsat imageryen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2007JG000622


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