|Beeri, Ofer - UND,NGP CTR PEOPLE&ENVIR|
Submitted to: Journal of Geophysical Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 3, 2006
Publication Date: June 10, 2006
Citation: Phillips, R.L., Beeri, O., Liebig, M.A. 2006. Landscape estimation of canopy C:N ratios under variable drought stress in Northern Great Plains rangelands. J. Geophys. Res. 111, G02015, doi:10.1029/2005JG000135. Interpretive Summary: Satellite-based information for rangeland landscapes in the Northern Great Plains is needed by land managers for evaluating vegetation quality and for assessing climate change. Currently, remote sensing products lack physically meaningful values representative of range condition that are accurate under variable plant moisture conditions. This manuscript describes a new product for assessing rangeland vegetation quality (leaf carbon:nitrogen ratio) using satellite data available through Landsat 5 and ASTER sensors. We field tested this product and found low relative errors (1.5 and 3.1 RMSE) for quantifying leaf C:N using ASTER and Landsat 5, respectively, despite variable plant moisture conditions.
Technical Abstract: Rangeland vegetation quality in the North American Northern Great Plains can be estimated at a landscape scale under variable moisture conditions using a multi-spectral model developed and tested inter-seasonally on rangelands with two satellite sensors. Carbon:nitrogen ratios (C:N) for mixed-grass prairie rangelands were estimated using Landsat 5 imagery for three grazing treatments at four times during the growing season with <11% error. Carbon:nitrogen ratios also were estimated using ASTER imagery acquired May 20 with <14% error. Carbon:nitrogen ratios estimated from satellite pixels differed significantly among grazing treatments and collection dates, in agreement with measured plot C:N despite variable plant water content.