Submitted to: USDA Symposium on Natural Resource Management to Offset Greenhouse Gas Emissions
Publication Type: Abstract Only
Publication Acceptance Date: October 24, 2002
Publication Date: November 19, 2002
Citation: Hunt, E.R., Fahnestock, J.T., Kelly, R.D., Smith, W.K., Welker, J.M., Reiners, W.A. 2002. Carbon sequestration in two rangeland ecosystems from remote sensing and net ecosystem exchange [abstract]. In: USDA Symposium on Natural Resource Management to Offset Greenhouse Gas Emissions, November 19-21, 2002, Raleigh, North Carolina. p. 81.
With large areas of the globe covered by rangelands, the potential for carbon sequestration is significant. Aircraft eddy flux measurements of net ecosystem exchange (NEE) were acquired in 1999 over two southeastern Wyoming landscapes, a mixed-grass prairie and a sagebrush steppe. A linear relationship between NEE and the absorbed photosynthetically active radiation (APAR) was used to determine radiation use efficiency (RUE = 0.51 gC/MJ), which can be used with remotely-sensed vegetation indices to calculate gross primary production (GPP). Chamber measurements of ecosystem respiration in 1998 and 1999 were used to develop a functional relationship with daily average temperature; the Q10 of the relationship was 2.2. Using Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index (NDVI) and incident photosynthetically active radiation to determine APAR, GPP and respiration were calculated for 1995 to 1999. The sagebrush site was a net carbon sink, whereas the grassland site was in carbon balance. The use of remotely-sensed NDVI to determine areas of carbon sequestration avoids problems associated with small-scale sampling; NEE measurements are important data to parameterize these NDVI/APAR models.