HR: 1340h
AN: B43B-0281    [Abstracts]
TI: Quantifying Regional Range Condition for Erosion and Carbon Modeling
AU: * Wylie, B K
EM: wylie@usgs.gov
AF: SAIC, USGS EROS, 47914 252nd St., Sioux Falls, SD 57198 United States
AU: Fosnight, E A
EM: fosnight@usgs.gov
AF: SAIC, USGS EROS, 47914 252nd St., Sioux Falls, SD 57198 United States
AU: Smart, A J
EM: Alexander.Smart@sdstate.edu
AF: South Dakota State University, Department of Animal and Range Sciences, Dakota State University, Brookings, SD 57007 United States
AU: Zhang, L
EM: lizhang@usgs.gov
AF: SAIC, USGS EROS, 47914 252nd St., Sioux Falls, SD 57198 United States
AB: Time Integrated Normalized Difference Vegetation Index (TiNDVI) values have been demonstrated to be a surrogate for photosynthetic potential, gross primary productivity, and green biomass. Long-term trends in SPOT VEGETATION TiNDVI can identify areas associated with climate change, climate variation, and management and that seasonal NDVI metrics, like maximum NDVI, can be predicted from climate and other data. We investigated the difference between TiNDVI predicted from climate and soil data sets and observed TiNDVI as a means for identifying degraded or heavily grazed rangelands. Degraded or consistently heavily grazed rangelands represent areas with increased vulnerability to erosion or areas with low vegetation cover relative to climatic and soil potential. This approach compensates for variations associated with drought and wet years and reveals areas having TiNDVI greater or less than their climatic potential for a given year and was applied to rangelands in the Northern Great Plains from 1998-2001 at 1-km resolution. TiNDVI predicted from monthly precipitation, temperature, and soils data accounted for 70 percent of the variation in observed TiNDVI for 3,700 random rangeland locations sampled for each of the 4 years. Areas with observed TiNDVI similar to the TiNDVI estimated from climate (plus or minus the mean absolute error) were considered to be rangelands in fair condition. Annual maps showing low and high TiNDVI relative to their climatic potential TiNDVI were produced and areas that were consistently above or below their climatic potential from 1998 to 2001 were identified and mapped.
DE: 0428 Carbon cycling (4806)
DE: 0429 Climate dynamics (1620)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 0480 Remote sensing
SC: Biogeosciences [B]
MN: Fall Meeting 2005