HR: 1340h
AN: GC23A-1301    [Abstracts]
TI: Warming-Induced Shrub Expansion May Enhance Future Soil Carbon Storage on the Eastern Tibetan Plateau
AU: * Klein, J A
EM: jklein@nrel.colostate.edu
AF: Natural Resources Ecology Laboratory, Colorado State University Natural and Environmental Sciences Building, 2nd Floor, Fort Collins, CO 80523 United States
AU: Ojima, D
EM: dennis@nrel.colostate.edu
AF: Natural Resources Ecology Laboratory, Colorado State University Natural and Environmental Sciences Building, 2nd Floor, Fort Collins, CO 80523 United States
AU: Harte, J
EM: jharte@berkeley.edu
AF: University of California, Department of Environmental Science, Policy & Management 151 Hilgard Hall, Berkeley, CA 94720 United States
AU: Zhao, X
EM: xqzhao@mail.nwipb.ac.cn
AF: Northwest Plateau Institute of Biology, Chinese Academy of Sciences No. 59 Xiguan Street, Xining, Qinghai, 810001 China
AB: Our objective is to quantify how ecosystem carbon storage responds to climate variability and grazing on the eastern Tibetan Plateau and to compare results across a suite of study approaches: experimental manipulations, space for time observations, and biogeochemical modeling. Four years of experimental manipulations of climate and grazing resulted in a 25gm^-2yr^-1 increase in shrub foliar productivity with experimental warming; grazing dampened the warming-induced shrub expansion. There was no discernable change in soil carbon storage with warming. Examination of the soil carbon in ambient plots within meadow versus shrubland habitats demonstrates 3.5% more soil carbon at the shrublands (9.4%C) than at the meadows (5.9%C). These differences in soil carbon are likely due to the highly recalcitrant nature of the shrub leaf litter, which contains 33% lignin of the total dry leaf mass. The comparable figures are 11% for forbs and 18% for graminoids. The experimental plots are likely exhibiting a delayed response to experimental warming. We predict that over the longer-term, soil carbon storage will increase with warming-induced shrub expansion. We use the CENTURY ecosystem model to illuminate the biogeochemical consequences of shrub expansion in this region and to identify temporal aspects of this transformation. While future increased carbon storage is beneficial in terms of climate mitigation, the warming-induced shrub expansion will negatively affect the availability and quality of forage resources in this region. This highlights the potential conflict between management goals in ecosystems where local livelihoods are directly dependent upon ecosystem goods and services.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 1630 Impacts of global change (1225)
DE: 1640 Remote sensing (1855)
SC: Global Climate Change [GC]
MN: Fall Meeting 2005