<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Nancy F. Glenn</dc:contributor>
  <dc:contributor>Temuulen T. Sankey</dc:contributor>
  <dc:contributor>DeWayne R. Derryberry</dc:contributor>
  <dc:contributor>Matthew J. Germino</dc:contributor>
  <dc:creator>Jessica J. Mitchell</dc:creator>
  <dc:date>2012</dc:date>
  <dc:description>This paper presents a combination of techniques suitable for remotely sensing foliar Nitrogen (N) in semiarid shrublands – a capability that would significantly improve our limited understanding of vegetation functionality in dryland ecosystems. The ability to estimate foliar N distributions across arid and semi-arid environments could help answer process-driven questions related to topics such as controls on canopy photosynthesis, the influence of N on carbon cycling behavior, nutrient pulse dynamics, and post-fire recovery. Our study determined that further exploration into estimating sagebrush canopy N concentrations from an airborne platform is warranted, despite remote sensing challenges inherent to open canopy systems. Hyperspectral data transformed using standard derivative analysis were capable of quantifying sagebrush canopy N concentrations using partial least squares (PLS) regression with an &lt;i&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/i&gt; value of 0.72 and an &lt;i&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/i&gt; predicted value of 0.42 (&lt;i&gt;n&lt;/i&gt; = 35). Subsetting the dataset to minimize the influence of bare ground (n = 19) increased &lt;i&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/i&gt; to 0.95 (&lt;i&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/i&gt; predicted = 0.56). Ground-based estimates of canopy N using leaf mass per unit area measurements (LMA) yielded consistently better model fits than ground-based estimates of canopy N using cover and height measurements. The LMA approach is likely a method that could be extended to other semiarid shrublands. Overall, the results of this study are encouraging for future landscape scale N estimates and represent an important step in addressing the confounding influence of bare ground, which we found to be a major influence on predictions of sagebrush canopy N from an airborne platform.</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/j.rse.2012.05.002</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Remote sensing of sagebrush canopy nitrogen</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>