| Abstract: | 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 R2 value of 0.72 and an R2 predicted value of 0.42 (n = 35). Subsetting the dataset to minimize the influence of bare ground (n = 19) increased R2 to 0.95 (R2 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. |
| Genre: | Article |
| ProdID: | 70041489 |
| Citation Author: | Mitchell, Jessica J.; Glenn, Nancy F.; Sankey, Temuulen T.; Derryberry, DeWayne R.; Germino, Matthew J. |
| Citation Contributing Office: | Forest and Rangeland Ecosystem Science Center |
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| Citation End Page: | 223 |
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| Citation Language: | English |
| Citation Larger Work Title: | Remote Sensing of Environment |
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| Citation Phsyical Description: | 7 p. |
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| Citation Publisher: | Elsevier |
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| Citation Search Results Text: | Remote sensing of sagebrush canopy nitrogen; 2012; Article; Journal; Remote Sensing of Environment; Mitchell, Jessica J.; Glenn, Nancy F.; Sankey, Temuulen T.; Derryberry, DeWayne R.; Germino, Matthew J. |
| Citation Start Page: | 217 |
| Citation Volume: | 124 |
| Citation Year: | 2012 |
| Type: | citation/reference |
| Text: | Remote sensing of sagebrush canopy nitrogen; 2012; Article; Journal; Remote Sensing of Environment; Mitchell, Jessica J.; Glenn, Nancy F.; Sankey, Temuulen T.; Derryberry, DeWayne R.; Germino, Matthew J. |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/j.rse.2012.05.002 |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 11 Dec 2012 00:00 -0600 |
| Publisher: | Elsevier |
