HR: 1340h
AN: B23C-1508    [Abstracts]
TI: Spatially Explicit Modeling of Grazing Effect on Soil Organic Carbon Change in the Green River Basin, Wyoming
AU: * li, z
EM: zli@usgs.gov
AF: SAIC, contractor to the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science, 47914 252nd Street, Sioux Falls, SD 57103, United States
AU: Liu, S
EM: sliu@usgs.gov
AF: SAIC, contractor to the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science, 47914 252nd Street, Sioux Falls, SD 57103, United States
AU: Tan, Z
EM: ztan@usgs.gov
AF: SAIC, contractor to the U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science, 47914 252nd Street, Sioux Falls, SD 57103, United States
AB: Proper grazing can improve ecosystem production and enhance carbon sequestration, while overgrazing can lead to net emission of carbon into the atmosphere. It is challenging to quantify the impacts of grazing at a regional scale owing to the spatial and temporal changes of biophysical settings and land management practices. In this study, we quantified and evaluated impacts of grazing intensity on the dynamics of soil organic carbon (SOC) across the Green River Basin in southwestern Wyoming using a biogeochemical model (EDCM—erosion-deposition-carbon model) and remotely sensed data. We simulated responses of ecosystem carbon stocks (including SOC) and fluxes to various grazing scenarios. Results based on these simulations indicate that: (1) sagebrush-dominated shrublands accumulated less soil carbon than did grass-dominated area; (2) grazing could lead to a greater decrease in production and SOC in the shrubland than in the grassland under the same intensity and (3) a grazing intensity of 0.03 animal units per hectare could reduce SOC at a rate of 3.1 gC/m2/yr in shrublands, but SOC changed little in grasslands during 30 years of simulated responses. Our model simulations also show that conversion of shrubland to grassland can enhance soil carbon sequestration in the Green River Basin.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0466 Modeling
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: 2007 Fall Meeting