|Boutton, Thomas - TEXAS A&M UNIVERSITY|
|Briske, David - TEXAS A&M UNIVERSITY|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 2, 2003
Publication Date: February 2, 2003
Citation: DERNER, J.D., BOUTTON, T.W., BRISKE, D.O. GRAZING IMPACTS ON ECOSYSTEM CARBON STORAGE ALONG A PRECIPITATION GRADIANT IN GREAT PLAINS GRASSLANDS. SOCIETY FOR RANGE MANAGEMENT MEETING ABSTRACTS. 2003. Technical Abstract: Livestock grazing is the most prevalent land use in rangelands, and has the potential to alter carbon (C) storage through grazing-induced changes in ecosystem structure and function. We assessed the impact of long-term moderate livestock grazing on ecosystem C-storage along an east-west precipitation/productivity gradient in the central North American Great Plains. Grazing impacts on ecosystem C-storage were inconsistent along the precipitation gradient as grazing increased ecosystem C-storage by 24% in shortgrass prairie, but reduced ecosystem C-storage by 8% in both mid- and tallgrass prairies. Likewise, grazing impacts on soil organic carbon (SOC) to a depth of 30 cm differed along the precipitation gradient. Grazing decreased SOC by 4-7% in mid- and tallgrass prairies, but increased SOC by 31% in shortgrass prairie. Grazing reduced root C-storage by 13% in tallgrass prairie and 45% in midgrass prairie, but 6% more root C-storage was observed in grazed than ungrazed plots in shortgrass prairie. Aboveground biomass C was reduced by 30-44% with grazing at all sites along the precipitation gradient as a result of plant removal by grazing animals. Grazing strongly increased the proportion of C derived from C4 grasses in biomass and soil, and substantially increased C-storage in shortgrass prairie, but not in the two more mesic environments. C-storage in Great Plains grasslands is most strongly influenced by rainfall; however, grazing did influence C-storage in shortgrass prairie where significant changes in functional composition of the plant community occurred.