Skip to main content
ARS Home » Pacific West Area » Logan, Utah » Forage and Range Research » Research » Publications at this Location » Publication #194571
Title: SCALING-UP OF CO2 FLUXES TO ASSESS CARBON SEQUESTRATION IN RANGELANDS OF CENTRAL ASIA

Author
item WYLIE, BRUCE - USGS EROS DATA CENTER
item GILMANOV, TAGIR - SOUTH DAKOTA STATE UNIV
item Johnson, Douglas
item SALIENDRA, NICANOR - U.S. FOREST SERVICE
item TIESZEN, LARRY - USGS EROS DATA CENTER
item DOYLE, RUTH - USGS EROS DATA CENTER
item LACA, EMILIO - UNIV OF CALIFORNIA

Submitted to: Forest Service General Technical Reports
Publication Type: Proceedings
Publication Acceptance Date: 1/7/2005
Publication Date: 6/1/2006
Citation: Wylie, B.K., Gilmanov, T.G., Johnson, D.A., Saliendra, N.Z., Tieszen, L.L., Doyle, R., Laca, E.A. 2006. Scaling-up of CO2 fluxes to assess carbon sequestration in rangelands of Central Asia. p.111-119. In: Rangelands of Central Asia: Proceedings of the Conference on Transformations, Issues, and Future Challenges. RMRS-p.39, USDA-FS Rocky Mountain Res. Sta., Fort Collins, CO.

Interpretive Summary: Concentrations of carbon dioxide in the atmosphere are increasing and may lead to global changes so slowing the increase of atmospheric carbon dioxide is important. Plants absorb carbon dioxide through photosynthesis to form biomass and ultimately soil organic matter. Increased plant productivity on rangelands could, therefore, contribute to offsetting increased atmospheric carbon dioxide. Although rangelands have lower rates of carbon absorption than forests, rangelands cover a vast area that represents about 40 percent of the earth's land surface and could be important for offsetting increases in carbon dioxide. Flux towers are micrometeorological instruments that quantify changes in carbon dioxide between the atmosphere and land surface. Because flux tower equipment and operation is both expensive and complex, relatively few flux towers can be placed on sites across the landscape. Therefore, the ability to scale up localized flux tower observations to broader geographical areas is critical to quantify and understand carbon dynamids. In our study, we analyzed carbon flux data sets from the Northern Great Plains in North America and the Kazakh Steppe in Central Asia. We found similarities in latitude, precipitation, and carbon fluxes between the two regions. This allowed us to combine carbon flux data, satellite data, and geographical data from these two regions to map important carbon budget data. Our approach provided an effective method for the regional mapping of carbon dynamics in the Northern Great Plains of North America and the Kazakh Steppe of Central Asia.

Technical Abstract: Flux towers provide temporal quantification of local carbon dynamics at specific sites. The number and distribution of flux towers, however, are generally inadequate to quantify carbon fluxes across a landscape or ecoregion. Thus, scaling up of flux tower measurements through use of algorithms developed from remote sensing and GIS data is needed for spatial extrapolation of carbon fluxes and to identify regional sinks and sources of carbon. Spatial and temporal quantification of carbon dynamics also may be useful in understanding the biophysical factors that cause regions to be sinks or sources of carbon. We analyzed data sets from the Northern Great Plains and the Kazakh Steppe and found similarities in latitude, precipitation, and carbon fluxes between the two regions. These similarities allowed us to pool carbon flux data, remotely sensed data and GIS data from these two regions to map gross primary productivity (Pg), total ecosystem respiration (Re), and net ecosystem exchange (NEE) for Kazakh Steppe for 2001 using regression tree techniques. We estimated 10-day Pg and Re with mean absolute errors of 3.2 and 2.7 g CO2/m2/day, respectively. The NEE for grasslands in the Kazakh Steppe during the growing season (April through October 2001) was 0.79 t C/ha. Localized carbon sinks and sources were positively correlated with growing season precipitation and Pg. The regression tree technique provided an effective method for the regional mapping of carbon dynamics as seasonally quantified by flux towers in the Northern Great Plains of North America and the Kazakh Steppe of Central Asia.