Northern Arizona University - Detecting the Impacts of Nitrogen Pollution on Vegetation and Soils in Grand Canyon National Park

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This is a notice of intent only. This task agreement will investigate the potential of spectroscopy and remote-sensing to detect N induced changes in 1) dominant trees and shrubs, and 2) understory vegetation (including invasive annuals) and biological crusts. Satellite-based hyperspectral systems, such as the EO-1 Hyperion platform, are untested for mapping foliar N concentrations for arid land annual and perennial grasses and forbs, but will soon provide global measurements of vegetation at an unprecedented spectral and temporal resolution (e.g., NASA HyspIRI satellite sensor), enhancing the potential applicability of these techniques. For this study, the application of field and laboratory spectrometer measurements will be used to develop and test techniques for quantifying foliar N levels which can be combined with remotely sensed data to monitor changes in vegetation composition and productivity and biological soil crusts. Remote sensing methods to map foliar N levels are important to estimating the impact of many dynamic ecosystem processes such as climatic variation, change in nutrient cycling cause by forest disturbances and the effects atmospheric N deposition on plant community composition and structure (McNeil et al. 2008). Changes in foliar N levels for southwestern tree species are hypothesized to be related to N deposition gradients and concomitant changes in productivity, structure and composition of annual plants and soil crusts. Once calibrated, spectroscopy and remote sensing-based vegetation monitoring may help to inform NPS land management planning and policy measures designed to protect Grand Canyon National Park (GCNP) air quality and natural resource values impacted by N deposition.

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